Heat Pump Service. HEAT PUMPS TOTAL ELECTRIC UNIT CAPABLE OF PROVIDING HEATING AND COOLING MOVES HEAT WITH REFRIGERATION SYSTEM. CURRENT TECHNOLOGY ALLOWS.

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Heat Pump Service

HEAT PUMPS

• TOTAL ELECTRIC UNIT CAPABLE OF PROVIDING HEATING AND COOLING

• MOVES HEAT WITH REFRIGERATION SYSTEM.

• CURRENT TECHNOLOGY ALLOWS US TO ABSORB ENERGY FROM THE OUTDOOR AIR EFFICIENTLY, DOWN TO 20º.

• During the winter months the heat pump absorbs heat from the outdoor air.

• Then releases the heat (energy) into the indoor air.

• There is energy (heat) present to minus 460º.

• Just as it is more efficient to move an object than it is to build or make one. It is more energy efficient to move heat, than generate it (depending on thermal/economic balance points).

• Heat pumps are sized for the cooling demand of the application.

• The heat pump will be the sole source of cooling for the application. It may be the only source of heat, depending on heating requirements.

• Most areas of the country will also require an additional source of heat. This may be as little as a 5KW heat strip, or as much as a 80,000 BTU furnace.

• We’ll look at this in more detail later.

HEAT PUMPS

• COOLING SEASON– HEAT PUMP PERFORMS THE SAME AS

ANY AIR CONDITIONING SYSTEM BY PICKING UP HEAT FROM THE SPACE TO BE CONDITIONED AND REJECTING IT OUTDOORS

HEAT PUMPS

• HEATING SEASON– UNIT ABSORBS HEAT FROM THE

OUTDOOR AIR AND MOVES IT TO THE CONDITIONED SPACE

– REVERSE-CYCLE AIR CONDITIONERS

HEAT PUMPS

• CLASSIFIED BY: THE SOURCE OF HEAT DURING THE HEATING CYCLE AND THE MEDIUM TO WHICH THE HEAT IS TRANSFERRED– AIR-TO- AIR– WATER-TO-AIR

INSIDE THE HEAT PUMP• COMPRESSOR CAPABLE OF OPERATING AT

LOW OUTDOOR TEMPERATURES

• INDOOR / OUTDOOR COIL DESIGN

• METERING DEVICE FOR INDOOR / OUTDOOR COIL

• REVERSING VALUE ( 4-WAY VALUE )

• ACCUMULATOR

• CRANKCASE HEATER

• AUXILIARY HEAT

• EMERGENCY HEAT

• DEFROST CYCLE

HEAT PUMP• ACCUMULATOR

– CLIMATUFF - PART OF COMPRESSOR SHELL– LOCATED IN SUCTION LINE BETWEEN THE COMPRESSOR

AND REVERSING VALUE

– WHY HAVE ONE?• MOST IMPORTANT:

– HEATING CYCLE - COLD TEMPERATURES, OUT DOOR COIL MAY NOT BE ABLE TO EVAPORATE ALL THE REFRIGERANT

– END OF DEFROST CYCLE– LIQUID CARRYOVER WILL BE CAUGHT BY THE

ACCUMULATOR TO PREVENT COMPRESSOR DAMAGE

WHAT MAKES A HEAT PUMP UNIQUE

• SPECIAL COMPRESSOR• MUCH HIGHER COMPRESSION RATIO• MOST SEVERE APPLICATION • HEAT PUMP COILS

– ALTERNATELY FUNCTION AS EVAPORATOR AND CONDENSER

– MUST TOLERATE CHARGE IMBALANCE

– OUT DOOR COIL MUST BE DESIGNIED FOR EASY DEFROST

HEAT PUMP

• CRANKCASE HEATER – LOCATED ON COMPRESSOR, OLDER

SYSTEMS USED COMPRESSOR WINDINGS.

– RAISES TEMPERATURE OF OIL SO THAT THE ABSORPTION OF REFRIGERANT INTO THE COMPRESSOR IS KEPT TO A MINIMUM

COOLING CONDITIONINDOOR COIL

SAT. SUCT. T. 41FENT. AIR T. 76F

OUTDOOR COIL

SAT. COND. T. 120FENT. AIR T. 90F

4-WAYVALUE

SUCT. P. 70 PSIGSUCT. T. 52FSUPERHEAT 11F

DISCHARGEPRESSURE 260 PSIG

METERINGDEVICE

SUBCOOLING10F

COMPRESSOR

HEATING CONDITIONSINDOOR COIL

OUTDOOR COIL

METERINGDEVICE

SUBCOOLING10F



4-WAYVALUE


METERINGDEVICE

SUBCOOLING10F


COMPRESSOR

HEAT PUMP

• TOTAL HEAT REJECTED EQUALS

HEAT ABSORBED + HEAT OF COMPRESSOR

THE REVERSING VALUE CONTROLS THE

DIRECTION

THE REFRIGERANT FLOWS

HEAT PUMP

COOLING CONDITIONINDOOR COIL


OUTDOOR COIL


4-WAYVALUE



METERINGDEVICE

SUBCOOLING10F

COMPRESSOR

HEATING CONDITIONSINDOOR COIL

OUTDOOR COIL

METERINGDEVICE

SUBCOOLING10F



4-WAYVALUE


METERINGDEVICE

SUBCOOLING10F


COMPRESSOR

Heat pump Thermostats

• Thermostats with adjustable heat anticipation need to have it adjusted for proper operation!

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 NO

RM

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

BAYSTAT239 OR 240

HEAT PUMP THERMOSTAT

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

Fault Indication Light

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

Fault Indication LightSOV Energized In Cooling

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A


Brings On Compressor In Both Heating And Cooling

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A


Brings On Compressor In Both Heating And CoolingEnergizes Auxiliary Heat When Unit Is In Defrost

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A


Brings On Compressor In Both Heating And CoolingEnergizes Auxiliary Heat When Unit Is In DefrostBrings On Indoor Fan

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A



Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’stats

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

Fault Indication LightSOV Engerized In Cooling


Part of Heat Anticipation Circuit (Used with Trane Electro-Mechanical T’statsThis Is The Second Stage-Brings On The Electric Heat

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A




Functions As An Internal Connection For The Blue Light

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A




Functions As An Internal Connection For The Blue LightThis Is The Common Side Of The Transformer

This Is The Other Side Of 24 Volts From The Transformer

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A




Functions As An Internal Connection For The Blue LightThis Is The Common Side Of The Transformer

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 NO

RM

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

BAYSTAT239 OR 240

HEAT PUMP THERMOSTAT

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

FAN ON - ON C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

BAYSTAT240A

COOLING ON FAN - AUTO

COOLING ON

FAN - AUTO

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

BAYSTAT240A

R

Y

X2

O

BL

BL

Y

O

Defrost Board

OD

S-A

R/W

OUTDOOR UNIT

COOLING ON FAN - AUTO

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

HEATING - ON - FIRST STAGE

FAN - AUTO

OD

A

15 TO 22 VOLTS (T) FROM ODS-A TO (R)

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

BAYSTAT240A

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

R

Y

X2

O

BL

BL

Y

O

Defrost Board

OD

S-A

R/W

INDOOR UNIT

R

B

G

W1

OUTDOOR UNITBAYSTAT240A

HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

HEATING - ON - 2ND STAGE

FAN - AUTO

OD

A


HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OFF

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2FA

N

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

24 VOLT S (X2) FROM DEF. BRD

24 VOLT S (O) FROM DEF. BRD


HE

AT

CO

OL

F

O

Y

X2

G

T

W

U

B

R

OF

F

RH

S-1 N

OR

M

TS

SM-2

CO

OL

HE

AT

RH

S-2F

AN

AUTO

ON

HACA

BL

RD

TSH

NORM

C1

H1

OD

A

INDOOR UNIT

R

B

G

W1

BAYSTAT240AHEATING ON EMERG. HTG

(OPERATES 1.5° BELOW SETPOINT)

FAN - AUTO

WHAT IS COOLING DROOP?

• Cooling droop is caused by the cooling anticipator heating up during the off cycle, causing the t’stat to come on sooner, to help overcome the thermal lag of the system.

• This also provides night time cooling that helps keep humidity under control

DROOP (cont’)

• Then there is Heating Droop.

• Heating Droop moves the temperature in the wrong direction. To compensate for this, the “T” circuit is added.

WHAT DOES THE “T” CIRCUIT HAVE TO DO WITH

ANYTHING?

• The “T” circuit is a heat anticipation circuit that adds heat to the thermostat to slow down thermostat response, and removes heat to speed up the response.

“T” Circuit

• As the outdoor temperature drops, the resistance in the “T”, actually a thermistor (ODS-A), goes up.

• The higher the resistance, the less voltage is supplied to the resistor (ODA) located inside the thermostat.

• The less voltage to the ODA, the colder the t’stat thinks it is.

Temperature Resistance-40 9500-35 6400-30 5400-25 4450-20 3700-15 3200-10 2700

-5 24000 19505 1700

10 145015 115020 107025 92035 72040 62045 54550 48055 42060 37065 33070 28575 26080 23085 20590 18595 165

100 145105 130110 115115 110

Defrost Thermister Resistance

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

10000

-40

-30

-20

-10

0 10

20

35

45

55

65

75

85

95

105

115

Outdoor Te m pe ra ture

Resistan

ce

RE

SIS

TA

NC

EDEFROST THERMISTOR RESISTANCE

10000

9000

8000

7000

6000

5000

4000

3000

2000

1000

OUTDOOR TEMPERATURE

-40 0 35 75 115

400013.6 V

.047 W .036 W

ODS-A-20°F.0034 A 3000

10.4 V

4000

.047 W

20009.6 V.046 W

0°F

.036 W

.069 W

-20°F13.6 V ODS-A

.0034 A 300010.4 V

ODS-A.0048 A 3000

14.4 V

4000

2000

.031 W

800

13.6 V.047 W

9.6 V.046 W

0°F

.036 W

.069 W

ODS-A-20°F.0034 A 3000

10.4 V

ODS-A.0048 A 3000

14.4 V

5 VODS-A 30°F.0063 A 3000

19 V.119 W

4000

.047 W

300

.013 W

0°F

-20°F13.6 V

20009.6 V.046 W

.031 W

800

.036 W

.069 W

ODS-A.0034 A 3000

10.4 V

ODS-A.0048 A 3000

14.4 V

5 VODS-A 30°F.0063 A 3000

19 V.119 W

2.2 VODS-A 70°F.0073 A

300021.8 V

.159 W

OD

MotorBR/BL

230 VOLTS

R

Y

RD/W

BK

O

BL

Y

O

T

T

AM

B.

CO

L

SENSORS

T’STAT

SOV

F

Y

O

R

X2

B

COMPR

T

K1

K2

DEFROST BOARD DURING DEFROST

WHY IS THE BLUE LIGHT ON?

THE BLUE LIGHT IS AN INDICATION THAT THE AUXILIARY HEAT IS ON.

• It is on in several instances.– If the t’stat is adjusted above set point.– If the outdoor temperature is below 40°F it will

cycle off and on to maintain room temperature.

• If it stays on constantly above 30°F or cycles on when the outdoor temp. is above 50°F, the system should be checked.

WHY IS THE RED LIGHT ON STEADY?

The Red Light on steady is an indication the Emergency Heat

Switch is on.• The switch is used only if the heat pump is

inoperative, but not due to a power failure.

• Using the heating in this mode will increase your power consumption.

• The red light is to remind the customer that the temperature is being controlled by resistance heat only.

THE RED LIGHT ON, BUT IT IS FLASHING

The Emergency Heat switch is in the Normal position.

RED LIGHT FLASHING

• If the red light is flashing, this is an indication that the defrost board has detected a defrost fault.

• Reset by moving the Emergency Heat Switch to the “on” position for 30 seconds.

• If the flashing returns, service on the heat pump may be required.

HEAT PUMP

REVERSING VALUE

ILLUSTRATION

.TP-4 .TP-3

. TP-2

.TP-1

SUCTION LINE

INDOOR COILOUT DOOR COIL

COMPRESSOR DISCHARGE

. . .

.

FROM OUTSIDE COIL

TO ACCUMULATOR

TOINDOOR COIL

TP-4TP-3

TP-2

TP-1FROM COMPRESSORDISCHARGE LINE

HEATING MODE

5FMAX TEMP.

DIFFERENCE

..TP-4 . TP-2

.

... TP-1

. .. TP-3

TO OUTDOOR COIL

TO ACCUMULATOR

FROM INDOOR COIL

FROM COMPRESSOR DISCHARGE LINE

COOLING MODE

5FMAX TEMP.

DIFFERENCE

HEAT PUMP

• METERING DEVICES– HEATING CYCLE, REFRIGERANT IS

METERED TO THE OUTDOOR COIL– COOLING CYCLE, REFRIGERANT IS

METERED TO THE INDOOR COIL

HEAT PUMP

• METERING DEVICES

• REFRIGERANT METERED TO COIL WHICH ABSORBS HEAT

• HEATING CYCLE REFRIGERANT METERED TO OUTDOOR COIL

• COOLING CYCLE REFRIGERANT METERED TO INDOOR COIL

METERING DEVICES

• CAPTUBE

• FIXED ORFICE

• TXV

METERING DEVICES

CHECK VALVESHUT

CHECK VALUEOPEN

METERING DEVICE

METERINGDEVICE

FLOW IS METERED

FLOW BYPASSES METERING DEVICE

The role of the defrost control

• To extract heat from the outdoor air, the heat pump must lower it’s outdoor coil temperature below that of the outdoor ambient.

• Depending on the humidity and temperature, frost may form on the outdoor coil.

• This frost will insulate the coil from the outdoor air, reducing it’s ability to absorb the heat from the outdoor air.

HEAT PUMP DEFROST CONTROLS

• - CONTROLS THE DEFROST CYCLE IN A HEAT PUMP DURING HEATING OPERATION.

• - THE DEFROST CONTROL CONTROLS THE FOLLOWING FUNCTIONS:

• 1 - SWITCH OVER VALVE OR REVERSING VALVE

• 2 - OUTDOOR FAN MOTOR

• 3 - ELECTRIC OR GAS AUX. HEAT

• 4 - INDICATES A FAULT HAS OCCURRED (OPTIONAL)

• - CONTROL THAT ESTABLISHES THE NEED FOR A DEFROST

• - BOTH TIMED AND DEMAND CONTROLS ARE USED TODAY

• - ELECTRO MECHANICAL TIMERS AND PRESSURE SWITCHES USED IN THE PAST

Heat pump defrost controls

• Several types of defrost controls have been used through the years.

• We will discuss their function and diagnostics of each type.

• The newer solid state and Demand Defrost controls will be the main focus of our time today.

As the frost accumulates on the outdoor coil, the systems capacity is reduced.

Ö To remove the frost/ice from the outdoor coil, the system will shift itself into a variation the cooling mode.

Ö During a defrost cycle the outdoor fan will stop, leaving the heat in the coil to remove the frost.

Ö The type of defrost control system will dictate how much frost/ice is allowed to accumulate prior to initiating a defrost.

• SYSTEM IN COOLING MODE- -ENERGIZE REVERSING VALVE– DIRECTS HOT GAS TO OUTDOOR COIL

TO MELT THE FROST

DEFROST CYCLE

DEFROST CONTROLS

• THE MUCH OLDER EQUIPMENT UTILIZED ELECTRO-MECHANICAL TIME CLOCKS.

• ELECTRONIC TIMER - TIME & TEMPERATURE DEFROST

• SOLID STATE - DEMAND DEFROST

DEFROST CYCLE

• TEMPERING INDOOR AIR– ELECTRIC HEAT IS TURNED ON TO

TEMPER THE AIR DURING DEFROST CYCLE.

DEFROST CYCLE

• OUTDOOR FAN OFF– ENHANCES DEFROST

Electro-Mechanical systems

ç All electro-mechanical systems are a “time/temperature” based control.

ç A predetermined amount of time must pass before a defrost cycle can be initiated.

ç As mentioned earlier, the outdoor conditions have major impact on the amount of defrost needed.

ç These systems are temperature activated as well.

Large amounts of frost may accumulate before the “Time” has elapsed.

• This results in lower seasonal efficiency.

• The reduced capacity will result with a greater dependence on a secondary heat source.

ELECTRONIC TIME-TEMPERATURE DEFROST CONTROL

• 50 - 70 - 90 MINUTE COMPRESSOR RUN TIME SELECTION

• 10 MINUTE TIME OVERRIDE IN DEFROST CYCLE• TWO TEST PINS - ADVANCES ELECTRONIC

TIMER AND PUTS SYSTEM INTO DEFROST CYCLE FOR TESTING

• ON BOARD DEFROST RELAYS FOR OUTDOOR FAN, SOV VALVE AND AUXILIARY HEAT

• DEFROST TERMINATED ON TIME OR TEMPERATURE

• COMPRESSOR RUN TIME IS KEPT ONLY WHEN COIL THERMOSTAT IS CLOSED

• The defrost thermostat is set to close at 25º.

• When the DT is closed, supplying 24 VAC to the D terminal, jumpering the test pins will speed up the internal clock.

• If you are testing the system, and have a jumper from R to D, remove the jumper as soon as the system shifts into defrost. To prevent excessive refrigerant pressures.

• These controls will default to the 90 minute setting if the selector jumper is not connected. Which is how the equipment is shipped.

• I recommend one of the shorter time settings, 50 or 70 minutes.

• The water run off from a unit in defrost is pure water, and has never been reported to caused roof damage to date!

• Trying to catch the water could damage the outdoor coil (if the collected water froze and backed up under the coil).

TST EDR R R B B X2 Y O O D T








There are several versions of these DFC boards. Many feature the exact same functions, with the only difference being the terminal for the defrost thermostat being labeled “D” or “DT”.









90 70 50 TST EDR R R B B X2 Y O O D T

DFC

CNT1152ORCNT1642

1

CNT1152 may be replaced by CNT 1642

1

K2

M1

M2

ODFAN

K1

24V AC24V COMMON

INDOOR THERMOSTAT

DT

MS

SC

DT

SC

TR TR1

EDC OR LPCO MS

F

G

EDR EDR

DFCCNT1642

K1 K2

M1

M2

ODFAN

90 70 50 TST EDR R R B B X2 Y O O DT T

X2

YOT

INDOOR THERMOSTAT

24V AC 24V COMMON

INDOORTHERMOSTAT

COMMON FORELECTRIC HEATER

ECONOMIZER(OPTIONAL)

TIMER DEFROST CONTROLTIMER DEFROST CONTROL

DEMAND DEFROST

CONTROLS

DEMAND DEFROST

• FEATURES – ADAPTABILITY– LEARNING PROCESS– DEFROST ON DEMAND– DIAGNOSTICS – TIME OVERRIDE– SOFT SWITCHOVER

DEMAND DEFROST CONTROLSDEMAND DEFROST CONTROLS

HEAT PUMP DEMAND DEFROST CONTROLS

• - TRANE DEMAND DEFROST CONTROLS OPERATE IN AN ADAPTIVE PROCESS TO OPTIMIZE THE HEAT PUMP PERFORMANCE.

• - THE DEMAND DEFROST CONTROL WILL ADAPT TO THE HEAT PUMP IT IS INSTALLED ON AND LEARN ITS OPTIMUM DEFROST CONDITIONS AND STORE THEM IN MEMORY.

• - THE DEMAND DEFROST CONTROL WILL ADJUST THE TIME BETWEEN DEFROST CYCLES TO MATCH THE WEATHER CONDITIONS.

HEAT PUMP DEMAND DEFROST CONTROLS

• - THE DEMAND DEFROST CONTROL WAS DEVELOPED BY TRANE IN 1984 AND IS PATENTED.

• - HEAT PUMP SYSTEMS WITH DEMAND DEFROST CONTROLS BENEFIT FROM A 6% HEATING SEASONAL PERFORMANCE FACTOR (HSPF) ADVANTAGE.

• - THERMISTOR SENSORS SENSE THE OUTDOOR AMBIENT TEMPERATURE AND OUTDOOR COIL TEMPERATURE.

• - THE DIFFERENCE BETWEEN THE OUTDOOR TEMPERATURE AND THE OUTDOOR COIL TEMPERATURE IS CALLED THE DELTA TEMPERATURE OR JUST DELTA-T.

The Defrost Cycle is Initiated • As ice builds on the coil, the delta-t of the system increases until

it reaches the initiate value, and the control starts the defrost process.

• The initiate value is not constant, but instead, is a value that the defrost control has learned will provide a fast, thorough defrost at a given outdoor temperature.

• Low initiate values waste energy by defrosting too often, while high initiate values fail to defrost the coils thoroughly.

• The control is continually varying the initiate value slightly to learn the best value.

• It measures the success of each initiate value by measuring the delta-t of the system during the next heating cycle.

DEFROST IS TERMINATED• Once the temperature of the outdoor coil reaches the

termination value, the defrost control turns on the outdoor fan. After waiting the soft-switch over time, it changes the switch over valve to the heating mode.

• This soft-switch over delay time, 12 seconds, gives the outdoor coil time to cool, reducing the refrigerant pressure and reducing the surge that occurs when the switch over valve is switched.

• If the compressor or “Y” cycles off during defrost, the switchover valve remains energized but the “X2” output will be OFF. If “Y” cycles off during the soft-switchover time, the switchover valve is switched OFF immediately.

Demand Defrost Control Operation

• Requirements for defrost initialization

• 1 - The outdoor temperature must be less than 52 F

• 2 -The coil temperature must be less than 33 F

• 3 -The Y line must be energized for a least 128 seconds

• 4 -The delta-T must be greater than the initiate temperature

• 5 - It must be time for a timed defrost

• 6 -30 minutes of run time have passed since the unit was first powered up

Demand Defrost Control Operation

• If the unit is placed into a forced defrost by placing the test jumper in the FRC DFT position and Y is energized, none of the above conditions need to be met.

• Defrost Controls groups 8 thru 21 have a 6 hour forced defrost below 6 degrees F outdoor temperature with a 3 minute timed override.

Requirements for Defrost Termination

• The coil temperature must exceed the terminate value.• If the outdoor temperature is greater than 22 F, the terminate

value is 47 F.• If the outdoor temperature is less than 10 F, the terminate

value is 35 F.• If the outdoor temperature is between 10 F to 22 F, the

terminate value is 25 F plus the outdoor temperature.OR

• The defrost control has a for 15 minute override time.

The Test Mode• The control may be placed into a test

mode by placing the RED jumper wire on the TST pin.

• This will cause the LED to blink rapidly and the operation of the control will be five times faster.

• The controller will run normally once the jumper is removed from the TST pin.

Fault Indications• There are three types of faults the demand defrost control can

experience.• All three faults can cause the defrost control to change from a

demand defrost control to a timed defrost control which defrosts the unit every 30 minutes.

• When the control goes into a timed defrost mode due to a FAULT A or FAULT C, on units that have the F line feature, it alerts the home owner by energizing the F line once every second which flashes a fault light on the thermostat.

• If the thermostat is switched to the emergency heat position, the F line will be energized, and the defrost control will be cleared of all faults after a few seconds.

Fault Indications• FAULT A is indicated by 2 led flashes per second.

• FAULT A is caused by one of two conditions:

• 1 - During heating the system's delta-T is unusually low.

• (The capacity of the system is lower than it should be.)

• 2 - After 12 minutes of operation since the defrost termination, delta-T is greater than the initiate value.

• After running in a FAULT A condition for 30 minutes, the defrost control will indicate it by flashing the LED. After running 2 hours with this fault, the demand defrost control will then change to a timed defrost operation, and the homeowner will be notified via the F line.

Fault Indications• FAULT A can be cleared by any one of the following

operations:

• 1 - If the control has two normal defrost cycles

• (If the fault has been present long enough for the Fault light to start Flashing, it will flash until the first normal defrost.)

• 2 - If power is removed from the defrost control for more than 30 seconds.

• 3 - If the F line is energized for a few seconds.

Fault A

Fault A

Fault A

Fault A

Fault A

Fault A

Fault A

Fault A

Fault A

Fault Indications• FAULT B is indicated by 3 led flashes per

second. • FAULT B is caused by 10 successive failures

of the heat pump to terminate on temperature during the defrost cycle.

• The unit will stop defrosting after 15 minutes due to the override timer.

• Once a FAULT B occurs, the control will indicate it by flashing the led. After FAULT B occurs 10 times, the control will act as a timer defrost control.

Fault Indications• FAULT B can be cleared by any one of the

following operations:• 1 - If the control reaches the terminate value

during one of the timed defrost cycles. • (Since this fault is pretty common in cold

climates with high winds, this fault does not alert the home owner via the F line.)

• 2 - If power is removed from the defrost control for more than 30 seconds.

• 3 - If the F line is energized for a few seconds.

Fault Indications• FAULT C is indicated by 3 led flashes per

second.

• FAULT C is caused by 15 successive faults in which the unit has an unusually high delta-T 15 minutes after a defrost termination.

• (Poor air flow over outdoor coils - they are probably blocked by ice.)

Fault Indications• FAULT C can be cleared by any one of the following

operations:• 1 - If the unit has a normal delta-T 15 minutes after a

defrost. (If the fault has been present long enough for the Fault light to start flashing, it will continue to flash until there is a defrost cycle without a high delta-T fault.)

• 2 - If power is removed from the defrost control for more than 30 seconds

• 3 -If the F line is energized for a few seconds

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Fault B or C

Combination Fault Indications

• FAULT A & FAULT B, indicated by 4 led flashes per second, is caused by 60 or more FAULT A's occurring and one or more FAULT B's occurring.

• FAULT A & FAULT C, indicated by 4 led flashes per second, is caused by 60 or more FAULT A's occurring and one or more FAULT C's occurring.

• Combination faults will notify the home owner by toggling the F line.• Combination faults can be cleared by any one of the following

operations:• 1 - If the F line is energized for a few seconds• 2 - If power is removed from the defrost control for more than 30

seconds

Power-up Initial Defrost• After the defrost board is powered up, its first defrost

cycle will be a timed cycle.• On the newer boards, the unit must run during

defrosting conditions for 30 minutes while some older boards must run for 45 minutes.

• Assuming there are no faults, subsequent defrost cycles will be performed on demand.

• The delay in each case can be reduced to 1/5 this time by placing the red jumper lead on the TST terminal.

Forcing the Unit to Defrost

• Placing the red jumper wire on the FRC DFT pin, the defrost board can be forced to initiate a defrost immediately even if outside temperature conditions are not met.

• The only requirement is that the compressor is running or the “Y” signal is present.

• The defrost will be terminated normally when the outdoor coil becomes hot enough.

• If the jumper is still on the FRC DFT lead upon defrost termination, it will initiate the defrost cycle again.

F Line Operation• Full featured defrost controls (G15-G17 & G19-

G20) have an F line to alert the home owner in the event of a fault.

• On older controls, the F line would continue to flash a fault to the home owner after the fault was gone, but newer boards stop flashing the Fault light after the faults A, B, and C have passed.

• This will hopefully cut down on nuisance service calls, and still yet alert the home owner if the heat pump fails.

No Fault Found

• DON’T REPLACE IT!– If LED blinks,– & Sensors ohm out OK,– & Forced defrost works.

• Look Elsewhere For Cause(s)

• Package Unit Ambient Sensor Bracket– Added for better ambient sensing

ODS-A Thermistor Failures

• Cause– Field miswire during installation

• Solution– X2 wire color changed from BR/X2 to BK

• DO NOT REPLACE CONTROL– Use RES0118 ODS-A kit– Needed ONLY for GE “blue light” thermostat

Defrost Control Failures• Early defrost controls would sometimes fail to defrost with the LED

steady ON or OFF. • If power is removed for 1 minute, the board will resume normal

operation. • After months of research at Trane and the microprocessor

manufacturer, the mechanisms for this type of failure were discovered, and the new defrost boards were designed and tested to resist this type failure.

• Defrost controls manufactured after Jan. 1995 have this improvement made.

Defrost Control Failures• The second problem is caused by miswiring.

• Often, the anticipator lead has been confused with the X2 lead, because the leads were both brown.

• In current generation outdoor units the “X2” lead is black, so the incidence of field miswiring should go down.

Temperature Sensors• The temperature sensors are temperature dependent

resistors encased in a heat-shrunk plastic shroud and sealed from air and moisture by a hot glue adhesive fill.

• The resistance of the sensor decreases as temperature increases according to a specified curve. See the temperature / resistance curve provided with the service information.

• It is rare for a temperature sensor to fail, and most that have been replaced in warranty were OK, or they had been damaged by rough handling.

Temperature Sensors• A common problem with sensors is damage

inflicted by forcing ohmmeter probes into their connectors. This permanently bends the contact causing an intermittent connection.

• On some package units, the sensor leads have been pinched by the access panel. Checking the sensor resistance to ground will detect this problem.

Check Out Procedure• The following tests are to be performed to check for

proper operation after installation of the demand defrost control.

• Step 1: Apply power to the system and operate in heating mode. The switchover valve should be off (heating mode), and the outdoor fan should be on.

• Step 2: Check to be sure the led on the defrost board is blinking once every second and the fault light on the thermostat is off.

• Step3: Force the system to defrost by placing the red jumper wire on the FRC DFT pin.

Check Out Procedure• As the unit goes through the defrost process, the

switchover valve should be energized, the auxiliary heat should be on and the outdoor fan motor should be off.

• Step 4: Monitor the system to be sure it stops defrost within 15 minutes.

• Step 5: At the end of the defrost cycle, the outdoor fan should come on, and after a 12 second delay, the unit will switch back to the heating mode.

Check Out Procedure• Step 6: If the board has the fault light feature (G15-G17&

G19-G20), test this feature by placing the red jumper wire on the FRC FLT pin for a few seconds then return the red jumper wire to the NORM pin.

• This should cause the led on the defrost board to blink four times a second, and the indoor fault indicator on the thermostat should be blinking once a second.

• Step 7: Switch the indoor thermostat to the emergency heating position for at least 30 seconds and then back to the heat pumps position.

• The indoor fault indicator should stop blinking and the LED should blink once a second indicating that everything is normal.

Helpful Hints in Case of Difficulty

• Led fails to blink on the defrost board

• If the led is off, check between R and B to be sure 24 volts is present.

• Remove power for one minute and re-apply power. Check to see if the LED starts flashing.


• LED flashes, but the unit fails the forced defrost test.

• 1. Be sure the red jumper wire was returned to the NORM pin.

• 2. Make sure the thermostat is calling for heating (24 V on Y)

• 3. Verify that the sensors are connected and mounted in the right places

• 4. Check the electrical connections to the defrost board (24V on O while defrosting)

• 5. There is a 1 minute minimum time in defrost under normal operation.

• If defrost is forced there is no minimum time in defrost.


• 1- The indoor fault indicator goes on and then goes off.

• During extreme weather conditions, the unit may have difficulty defrosting. This will cause a fault and alert the owner, but when the weather is more temperate, the fault will clear and the indicator will stop blinking.

• 2 - The outdoor sensor (ODS) is burnt on the defrost board.

• Check control wiring “T” and “X2” .

• On the newer units the X2 lead is black and this is not as likely to happen.

Demand Defrost ControlProblems

Excessive Ice Built-up on OD Coil• Low refrigerant charge

• Defrost Control will not InitiateA. No 24 VAC between R&B at defrost control

B. No 24 VAC between B&Y at defrost control with system running

C. Verify correct sensor location, mounting & their resistance

D. Verify ambient sensor is connected to AMB position on defrost control

E. Verify coil sensor is connected to coil position on defrost control


Excessive Ice Built-up on OD Coil

• SOV Inoperative

A. Stuck in heating mode

B. Open switchover valve (SOV) coil

C. Defective defrost control

• Defrost control contacts to OD fan fail to open during defrost cycle


Excessive Ice Built-up on OD Coil

• Defrost control terminates, but does not remove ice

A. Windy conditions

B. Outdoor unit located under eaves

C. Lack of proper drainage

D. Night setback operation

Ice Build Up on Lower Part of Outdoor Coil

• Low refrigerant charge

• Coil sensor connected to wrong pass of outdoor coil, or poor contact

• Leaking check valve (outdoor unit)

• Distributor tube restricted

• One pass of OD coil restricted

• Lack of proper drainage

Defrost Initiates, but Terminates Only on a Time Override

• Low refrigerant charge

• Outdoor fan on during defrost

• Windy conditions

• Night setback operation

• Unit location

• Coil sensor in contract with ice

• Coil sensor circuit open or reading very high resistance.

Defrost Cycle Initiates, but Will Not Terminate

• Defrost Control

• Switch-over valve stuck in cooling mode

Unit Goes Into Defrost In Cooling Mode

• Defective Sensors

• Defective Defrost Control

Control Terminates Defrost Before Frost Is Gone

• Coil sensor mounted in wrong location or has incorrect resistance reading

• Refrigerant overcharge

Defrost Initiates About Every 15 Minutes

• Coil sensor

• Ambient sensor

• Defrost control

Defrost Initiates About Every 30 Minutes. Fault Light on Indoor Thermostat Will Be

Flashing If Wired

• Coil sensor

• Ambient sensor

• Weather conditions

• Night setback operation

• Outdoor fan on during defrost

• System refrigerant charge

• SOV operation

Two-Compressor Controllers

• Tyler Version For V.S. OD Fan Motor– Cooling model

• 21C150624G02, CNT2275

– Heatpump model• 21C150625G02, CNT2276

Two-Compressor Controllers

• Ft. Smith Version for PSC Fan Motor– Cooling model

• 21C150624G01, CNT1858

– Heatpump model• 21C150625G01, CNT1859

Heat Pump Control

EFFICIENCY

• EER

• COP

• SEER

• HSPF

EERBTU’S OUT 39,000 BTU/HR.

POWER IN 4380 WATTS/HR.= 8.9 BTU/WATT

COPBTU’S OUT 39,000 BTU/HR

BTU’S WE 4380 WATTS/HR X 3.1413 BTU/WATT

PAY FOR

= 2.6

COP FOR HEAT PUMP AND RESISTANCE HEAT

0

1.0

2.0

3.0

4.0

-20 -10 0 10 20 30 40 50 60OUTDOOR TEMPERATURE

HE

AT

ING

CO

P

RESISTANCE HEAT

HEAT PUMP

HSPFHEATING SEASONAL PERFORMANCE FACTOR

• TOTAL HEATING OUTPUT OF A HEAT PUMP DURING ITS NORMAL ANNUAL USAGE PERIOD FOR HEATING DIVIDED BY THE TOTAL ELECTRIC POWER INPUT IN WATT-HOURS DURING THE SAME PERIOD

SEERSEASONAL ENERGY EFFICIENCY RATIO

• TOTAL COOLING OF A CENTRAL UNITARY AIR CONDITIONER OR UNITARY HEAT PUMP IN BTU’S DURING ITS NORMAL ANNUAL USAGE PERIOD FOR COOLING DIVIDED BY, THE TOTAL ELECTRIC POWER INPUT IN WATT-HOURS DURING THE SAME PERIOD

WHEN CAPACITY DROPSO

UT

DO

OR

TE

MP

ER

AT

UR

E EER&COP - CAPACITY - SUCTION - TEMPERATURE

PRESSURE

WHAT CAUSES CAPACITY TO DROP

GASDENSITY

DECREASES

SHORTEREFFECTIVE

STROKE

DECREASEDFLOW RATE

=+

CAPACITY VS. HEAT LOSSC

AP

AC

ITY

TEMPERATURE

UNIT CAPACIT

YHEAT LOSS

SUPPLEMENTALHEAT

NEEDED

ELECTRIC HEAT

• SUPPLEMENTAL HEAT

• EMERGENCY HEAT

• AUXILIARY HEAT

• RESERVE HEAT

THERMAL BALANCE POINT

HEAT LOSSHEATINGCAPACITY

=HEAT PUMP

CAPACITY VS. HEAT LOSS

BTU/HR

OUTDOOR TEMPERATURE

45,000

50F

21,000

HEAT LOSS

UNIT CAPACITY

10F

BALANCE POINT

HEAT LOSS

UNIT CAPACITY

BALANCEPOINT

OUTDOOR TEMPERATURE

BTU/HR

34,500

0 32.5F 65F

DESIGN POINT

HEAT LOSS

UNIT CAPACITY

OUTDOOR TEMPERATURE

BTU/HR

10F

57,500

21,000

DESIGN POINT

NEED36,500 BTU/HRADDITIONAL

EMERGENCY HEAT

HEAT LOSS

UNIT CAPACITY

10F

57,500

BTU/HR

OUTDOOR TEMPERATURE

57,500X 1.0057,500 BTU/HR

57,500 BTU/HR

3413 BTU/KW= 16.8 KW

TOTAL CAPACITYWITH 17 KW HEATER PACKAGE

UNIT CAPACITY1ST STAGE2ND STAGE

3RD STAGE

19,340 BTU/HR (5.66KW)19,340 BTU/HR

19,340 BTU/HR

BALANCE POINT1 ST STAGE ELECTRIC HEAT

UNIT CAPACITY1ST STAGE

OUTDOOR TEMPERATURE22.5F

HEAT LOSS

BALANCE POINT

BALANCE POINT2ND STAGE ELECTRIC HEAT


OUTDOOR TEMPERATURE

HEAT LOSS

BALANCE POINT

2ND STAGE

13F

BALANCE POINT3RD STAGE ELECTRIC HEAT


OUTDOOR TEMPERATURE

HEAT LOSS

2ND STAGE3RD STAGE

BALANCE POINT

4F 10F

DESIGNPOINT

BTU/HR

Heat pump with heat strips

• This application has a 17KW heat strip. You will see that W2 heat strip is brought on during defrost.

• The W1 and W3 heat strips are controlled by outdoor thermostats. Only bringing them on as the outdoor temperature drops.

TO LINE VOLTAGE SUPPLY

BR

/RD

PURPLE/WH

BK

/BL

PURPLE/WH BLACK BLACK

TDL SUMP HTR

BK/BLRD BR

MS-1 CSR-1 CSR CS

OR

OR

BK

/BL

S

R CPR IOLRD

CRRD

BR

/RD

BL/WHFANMTR

RED

R B B O O Y Y X2 FY1

RDYL

YLBK

BK

CBS

ODS-B

BK/RD

CF

PURPLE

BROWN

BLACK

OFT-BOFT-A

LO

HI

YLYLBK

BKY Y X2 FR B B O O

RD

T1

BLACK OR

YL

X BK

X BK X

X BK X

X BK X

HEATERCONTROLS

BR

BL

RD TO POWER SUPPLY PERLOCAL CODES

TYPICAL MANUAL CHANGE OVER THERMOSTATTYPICAL AIR HANDLER

O

Y

W3

W2

W1J

G

T

F

O

Y

X2

G

T

W

U

B

R

B

R

RD/WH

F YL BKOR RD BL

WS

ODS-AFANCONTROLBD

T

T

B

R

X2

Y

O

SM-1

HEAT OFF COOL

HA

CA

TSRHS-1

SM-2

HE

AT

CO

OL

RHS-2

FA

N

AUTO

ON

ODA

TSH

RD

BL

EMERGENCY HEAT RELAY PACKAGE

MAINTAINS COMFORT IF HEAT PUMP FAILS BY

1LOCKING

OUT COMPRESSOR

2BYPASSINGOUTDOOR

THERMOSTAT

3BRINGING

ON FULLSTRIP HEAT

SQUEEZING OUT OPERATIONG $

• DECREASE BALANCE POINT– OVERSIZE HEAT PUMP – UPGRADE BUILDING INS. & GLAZING– TURN DOWN THE THERMOSTAT

• DUAL - ALTERNATIVE HEATING SYSTEM

• 2 - STAGE HEAT PUMP

LOCATING THE UNIT • AIR CONSIDERATIONS

– AVOID RECIRCULATION

– CUT OFF PREVAILING WIND

• WATER DRAINAGE – ALLOW CLEARANCE FOR WATER DRAIN

OFF

• SNOW CONSIDERATIONS– AVOID SNOW DRIFTS

– RAISE UNIT IN HEAVY SNOW AREAS

AIR FLOW

CHARGING

LOAD CALCULATION

CAPACITY

DUALFUEL

HEATING “ON” CYCLE

FOSSIL FUEL

HEAT PUMP

TIME

TEMP

DUAL FUEL SYSTEMS• DEPENDS ON THE COST OF ELECTRICITY AND

PRICE OF THE FOSSIL FUEL• LESS EXPENSIVE TO HEAT COMPRESSION-

CYCLE EQUIPMENT WHEN THE OUTDOOR TEMPERATURE IS MILD TO MODERATELY COLD

• MORE ECONOMICAL TO HEAT WITH FOSSIL FUEL WHEN THE OUTDOOR TEMPERATURE IS VERY COLD

• REDUCES DEMAND FOR POWER DURING PERIODS OF COLD WEATHER

ECONOMIC BALANCE POINT

• OUTDOOR TEMPERATURE ASSOCIATED WITH EQUAL OPERATING COSTS

ADD-ON HEAT PUMP KITTYPLUS103A

• SEQUENCE OF HEATING OPERATION• NON-RESTRICTIVE MODE

– FIRST STAGE HEAT, HEAT PUMP (ONLY) OPERATES IN HEATING, IF HEAT PUMP CANNOT HANDLE THE LOAD , WHEN THE TEMPERATURE IN ROOM DROPS APPROX. 1-1/2F, FURTHER, SECOND STAGE HEAT IS CALLED FOR. SECOND STAGE TURNS THE HEAT PUMP OFF AND BRINGS THE FURNACE ON. FURNACE WILL SATISFY SECOND STAGE ONLY. FIRST STAGE IF CALLING WILL OPERATE AFTER 45 SEC. DELAY

– THERMOSTAT EMERGENCY HEAT POSITION OPERATES FURNACE ONLY

• SEQUENCE OF HEATING OPERATIONRESTRICTIVE MODE - ( REQUIRES TAYSTAT250A )

– O.D.T. CHANGEOVER AT OR ABOVE ECONOMIC BALANCE POINT

– TEMPERATURES ABOVE O.D.T.,HEAT PUMP ONLY,WHEN CALLED BY FIRST STAGE STAT.

– TEMPERATURES BELOW O.D.T.,FIRST STAGE STAT. GOES TO THE FURNACE AND HEAT PUMP IS CUT OFF

– EMERGENCY HEAT POSITION CONVERTS SYSTEM TO FURNACE ONLY OPERATION

ADD-ON HEAT PUMP KITADD-ON HEAT PUMP KITTYPLUS103ATYPLUS103A

AIR FLOWSUPPLY DUCT

UPFLOWFURNACE

NOTE 1

“A” COIL UPFLOWAPPLICATION

CLASS 2 LOW VOLTAGE WIRING TO SYSTEM CONTROLLER

COIL ENCLOSURE

BONNET THERMOSTAT

“A” COIL

FRONT COIL BAFFLE

NOTE:1. MOUNT BONNET THERMOSTAT THROUGH FRONT COIL BAFFLE AT THE HIGHEST PRACTICAL POINT INSIDE THE ‘A’ COIL SO THE SENSING ELEMENT DOES NOT TOUCH EITHER SLAB OF COIL OR INTERFERE WITH TUBING.

T O R W Y B X2 G

G

W1

W2

R

B

Y

FIELD WIRING DIAGRAM FOR SPLIT HEAT PUMP SYSTEM WITH TAYPLUS103A CONTROL IN FURNACE (UNRESTRICTED MODE)

ROOM THERMOSTAT

INTER-COMPONENT WIRING

24 V. FACTORY

LINE V. WIRING

24 V. FIELD

LINE V. WIRING

FIELD INSTALLED FACTORY WIRING

HEAT PUMPO.D. SECTION

BR T

OR O

YL Y

RD R

BL B

BR/X2 OR BK X2

3 PH. ONLY

TO POWER SUPPLY PERLOCAL CODES

LEGENDTDR - TIME DELAY RELAY MODEL RLY1664

K - RELAY MODEL RLY1663BT - BONNET THERMOSTAT MODEL THT1248

W3 Y3 X3 G3

G1

K1-3

K1-2

K1 TDR

TDR - 1

K1-1

Y2

X2

Y1 B W1

BT

3 PH. ONLY

TO POWERSUPPLY PERLOCAL CODES

TAYPLUS103A

FURNACE

T O R W Y B X2 G

G

W1

W2

R

B

Y

FIELD WIRING DIAGRAM FOR SPLIT HEAT PUMP SYSTEM WITH TAYPLUS103A CONTROL IN FURNACE (RESTRICTED MODE)

ROOM THERMOSTAT

INTER-COMPONENT WIRING

24 V. FACTORY

LINE V. WIRING

24 V. FIELD

LINE V. WIRING

FIELD INSTALLED FACTORY WIRING

HEAT PUMPO.D. SECTION

BR T

OR O

YL Y

RD R

BL B

BR/X2 OR BK X2

3 PH. ONLY

TO POWER SUPPLY PERLOCAL CODES

LEGENDTDR - TIME DELAY RELAY MODEL RLY1664

K - RELAY MODEL RLY1663BT - BONNET THERMOSTAT MODEL THT1248

W3 Y3 X3 G3

G1

K1-3

K1-2

K1 TDR

TDR - 1

K1-1

Y2

X2

Y1 B W1

BT

3 PH. ONLY

TO POWERSUPPLY PERLOCAL CODES

TAYPLUS103A

FURNACE

ODT

Component failures

• Component’s that fail after 30 days of operation, but prematurely. A 2 year old compressor or fan motor.

• If a component last for 100 hours of operation, but not 10,000 hours, odds are it is a symptom of another yet undiagnosed problem!

Mechanical problems that cause electrical failures

• Failure of start components or compressor? Compressor starting with liquid present!

• Overcharged unit.

• Crankcase heater circuit failure.

• Cycle rate too short, superheat never stabilizing.

• Low supply voltage is the least common, and most often assumed.

Things we need to get better at

• Gathering information from the consumer.

• Looking beyond the failure in front of us, why did it fail. Shit does not just happen!

• Charging, letting the system run long enough to stabilize. Taking subcooling and superheat.

• Remembering that over 50% of the electronic controls replaced didn’t need to be replaced!

The MOST important thing to remember

Trane technicians are proven to be the best!

The End

Thank you

Heat Pump Service. HEAT PUMPS TOTAL ELECTRIC UNIT CAPABLE OF PROVIDING HEATING AND COOLING MOVES HEAT WITH REFRIGERATION SYSTEM. CURRENT TECHNOLOGY ALLOWS.

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