Compressor Proving on ReliaTel Controlled Units

RTRM Compressor Proving Information

Compressor Proving faults on units with ReilaTel Controls indicates that the RTRM has commanded the compressor contactor on, but the RTRM did not detect that the contactor pulled in or the RTRM detected that the contactor opened while running. Based on the communication interface installed in the unit and the firmware on that interface, the diagnostic can come through in different ways including HPC Lockout or Disable alarms. See troubleshooting section below for alarms that can be generated on a BAS or a TD5 for each compressor. 

Note: All Ultra High Efficiency (Eflex) units with ReliaTel controls will have the a Compressor 3 regardless of how many compressors they actually have. The variable speed compressor on ReliaTel controlled units is always compressor 3. Compressor proving for these compressors is different and not covered in this document. 

Compressor 1 & 2 Proving Information

For CC1 & CC2, the RTRM has a built in current switch circuit that can detect the current the compressor contactor draws to "prove" the contactor is closed. This is why the neutral/ground side of the compressor contactor is wired back to the RTRM instead of wired to a neutral/ground point on the unit. CC1 and CC2 wiring is the same between all ReliaTel units:

For the current switch function to work on the RTRM J1-9/J3-3, the compressor contactor coil resistance should measure between 5-12 ohms with the coil wires disconnected. 

Compressor 3 Proving Information - Voyager 2

Compressor 3 on Voyager 2 is only found on High Efficiency 25T cooling only models (does not apply to variable speed compressor). CC3 on these units is controlled through an output that is normally used for the reversing valve 1 output on heat pumps or the HGRH valve on units with reheat. There is not current switch on these units for CC3 proving, instead, the 24vac that is commanded on for CC3 is sent back to the RTRM on J9-4 after the safeties. If DTL3 or HPC3 open while the CC3 is commanded on, the 24vac will drop to the contactor and the proving input resulting a diagnostic. 

Compressor 3 Proving Information - Voyager 3

Compressor 3 on Voyager 3 utilizes an the output for reversing valve 2 on heat pumps for CC3. There is not current switch on these units for CC3 proving, instead, Voyager 3 utilize a an auxiliary contact (AUX2) on the side of CC3. The AUX2 contact receives 24vac from TNS2 on the COM terminal and when the contactor is pulled in, sends that 24vac to RTRM J9-4. If PHM3, DTL3 or HPC3 open while the CC3 is commanded on, the 24vac will drop to the contactor causing it to open and AUX2 will drop the 24vac to the proving input resulting a diagnostic. 

Troubleshooting the compressor control/proving circuit for Compressor 1

Precedent/Voyager 2/Odyssey

1. Disconnect power to unit
2. Remove RTRM P1 connector from RTRM J1 connection (located to the right of the thermostat terminals, largest connector on the board

3. Check resistance between RTRM P1-9 and RTRM P1-10 (on the wires, not the board)
   • Total circuit resistance value should be between 5-12 Ω

4. If value is out of range (high) or open, check:

   • Check connection and status of DTL1 
   • Check connection and status  HPC1
   • Check the contactor coil resistance should measure between 5-12 ohms with the coil wires disconnected. 

   If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test"

Voyager 3

1. Disconnect power to unit
2. Remove RTRM P1 connector from RTRM J1 connection (located to the right of the thermostat terminals, largest connector on the board

3. Check resistance between RTRM P1-9 and PHM1 Y-Out (on the wires, not the board)
   • Total circuit resistance value should be between 5-12 Ω

4. If value is open, check:
   1. Note: Some V3 units may have a temperature driven compressor protection module on the compressor
   2. Check connection and status of DTL1
   3. Check connection and status  HPC1
   4. Check the contactor coil resistance, should measure between 5-12 ohms with the coil wires disconnected.
5. If this test shows a closed circuit, reconnect RTRM P1 to RTRM J1 and apply 24vac to PHM1 Y terminal to test 
   1. Note: This can energize the compressor contactor, it is recommended that the fuses for CC1 be removed or the load side of the contactor disconnected. 
   2. With 24vac applied to PHM1 Y, the PHM LED should be GREEN and passing 24vac to the rest of the circuit. A PHM that comes on with a RED LED indicates a potential reverse phase or loss of phase is detected at the PHM. 
   3. No LED on the PHM indicates either a faulty PHM or missing connection to neutral/ground on the COM terminal. 

If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test"

Possible Diagnostics for Compressor 1 Proving:

TD5 Display

• Comp 1 Disable Input/HPC (auto reset alarm)
• Compressor 1 HPC Lockout (manual reset alarm)

TCI/Tracer Summit

• Diag: Comp 1 High Press Cutout (auto reset alarm)
• Diag: Comp 1 Locked Out (manual reset alarm)

LCI-R & Rx(Lon/Comm5)

• Comp 1 Disable Input/HPC (auto reset alarm)
• Compressor 1 HPC Lockout (manual reset alarm)

BCI-R & BCI2-R

• BI-269, Diagnostic: Comp 1 Disable Input HPC (auto reset alarm)
• BI-47, Diagnostic: Compressor 1 HPC Lockout (auto reset alarm)

Troubleshooting the compressor control/proving circuit for Compressor 2

Precedent/Voyager 2/Odyssey

1. Disconnect power to unit
2. Remove RTRM P3 connector from RTRM J3 connection (located to top of the RTRM, 2nd connector from the left)

3. Check resistance between RTRM P3-3 and RTRM P3-4 (on the wires, not the board)
   • Resistance value should be between 5-12 Ω
4. If value is out of range (high) or open, check:
   • Check connections and status of the compressor phase monitor (Voyager 3 only)
     • Note: Some V3 units may have a temperature driven compressor protection module on the compressor
   • Check connection and status of DTL2 
   • Check connection and status  HPC2

   • Check the contactor coil resistance should measure between 5-12 ohms with the coil wires disconnected.

     If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test" 

Voyager 3

1. Disconnect power to unit
2. Remove RTRM P3 connector from RTRM J3 connection (located to top of the RTRM, 2nd connector from the left)

3. Check resistance between RTRM P3-3 and PHM2 Y-Out (on the wires, not the board)
   • Total circuit resistance value should be between 5-12 Ω

4. If value is open, check:
   • Note: Some V3 units may have a temperature driven compressor protection module on the compressor
   • Check connection and status of DTL2
   • Check connection and status  HPC2
   • Check the contactor coil resistance, should measure between 5-12 ohms with the coil wires disconnected.
5. If this test shows a closed circuit, reconnect RTRM P3 to RTRM J3 and apply 24vac to PHM2 Y terminal to test 
   • Note: This can energize the compressor contactor, it is recommended that the fuses for CC2 be removed or the load side of the contactor disconnected. 
   • With 24vac applied to PHM2 Y, the PHM LED should be GREEN and passing 24vac to the rest of the circuit. A PHM that comes on with a RED LED indicates a potential reverse phase or loss of phase is detected at the PHM. 
   • No LED on the PHM indicates either a faulty PHM or missing connection to neutral/ground on the COM terminal. 

If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test"

Possible Diagnostics for Compressor 2 Proving:

TD5 Display

• Comp 2 Disable Input/HPC (auto reset alarm)
• Compressor 2 HPC Lockout (manual reset alarm)

TCI/Tracer Summit

• Diag: Comp 2 High Press Cutout (auto reset alarm)
• Diag: Comp 2 Locked Out (manual reset alarm)

LCI-R & Rx(Lon/Comm5)

• Comp 2 Disable Input/HPC (auto reset alarm)
• Compressor 2 HPC Lockout (manual reset alarm)

BCI-R & BCI2-R

• BI-270, Diagnostic: Comp 2 Disable Input HPC (auto reset alarm)
• BI-48, Diagnostic: Compressor 2 HPC Lockout (auto reset alarm)

Troubleshooting the compressor control/proving circuit for Compressor 3 

Voyager 2

1. Disconnect power to unit
2. Remove RTRM P2 connector from RTRM J2 (top left corner) AND RTRM P9 connector from RTRM J9 (just above J1)

3. Check resistance between RTRM P2-7 and RTRM P9-4 (on the wires, not the board)
   • Typical resistance value should be between 5-12 Ω
4. If value is open, check:
   • Check connection and status of DTL3
   • Check connection and status  HPC3
   • Check the contactor coil resistance should measure between 5-12 ohms with the coil wires disconnected. 

If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test"

Voyager 3

1. Disconnect power to unit
2. Remove RTRM P2 connector from RTRM J2 (top left corner)

1. Check resistance between PHM3 Y-Out and CTB1 (control power neutral/ground)
   • Typical resistance value should be between 5-12 Ω 

3. If value is open, check:
   • Check connections and status of the compressor phase monitor (Voyager 3 only)
   • Note: Some V3 units may have a temperature driven compressor protection module on the compressor
   • Check connection and status of DTL3
   • Check connection and status  HPC3
   • Check the contactor coil resistance, should measure between 5-12 ohms with the coil wires disconnected. 
4. If this test shows a closed circuit, reconnect RTRM P3 to RTRM J3 and apply 24vac to PHM2 Y terminal to test 
   • Note: This can energize the compressor contactor, it is recommended that the fuses for CC2 be removed or the load side of the contactor disconnected. 
   • With 24vac applied to PHM2 Y, the PHM LED should be GREEN and passing 24vac to the rest of the circuit. A PHM that comes on with a RED LED indicates a potential reverse phase or loss of phase is detected at the PHM. 
   • No LED on the PHM indicates either a faulty PHM or missing connection to neutral/ground on the COM terminal. 

If these tests all check out, skip to the bottom of this article for "Testing the Proving Circuit on the RTRM" and "RTRM Compressor Relay Test"

Possible Diagnostics:

TD5 Display

• Comp 3 Disable Input/HPC (auto reset alarm)
• Compressor 3 HPC Lockout (manual reset alarm)

TCI-R/Tracer Summit

• None - Compressor 3 was never an option for TCI-R

LCI-R & Rx(Lon/Comm5)

• Comp 3 Disable Input/HPC (auto reset alarm)
• Compressor 3 HPC Lockout (manual reset alarm)

BCI-R & BCI2-R

• BI-301, Diagnostic: Compressor 3 HPC Disable
• BI-299 or BI-300, Diagnostic: Compressor 3 LPC Lockout Status

Testing the Proving Circuit on the RTRM

This testing applies to the the current switch circuits for CC1 & CC2. To properly complete this test, a meter capable of testing diodes ( ) and reading resistance up too 200k Ω is required.

RTRM J1-9 Compressor 1 Proving Current Switch Testing

1. Disconnect power to the unit
2. Remove RTRM P1 connector from RTRM J1 connection (located to the right of the thermostat terminals, largest connector on the board)
3. Count to pin 9 on RTRM J1 ( there is a -1 on the board on one end of J1 to denote pin 1)
4. Set meter for resistance (not the ringer) and measure resistance to a good ground (look for the same place that the transformers are bonded to for ground)
   • Value should be ~110k Ω +/- 20k ohms
   • Readings outside this range are a sign of a failed current switch and replacing the RTRM is recommended

5. Positive Forward Bias Test - Switch meter to diode test and put the red (+) lead of the meter on J1-9 and the black meter lead (-) on the same ground from earlier
   • Value should be between 0.5 - 1.2 vdc (~0.5 vdc is most common)
   • Values well below 0.5vdc are a sign of a failed current switch and replacing the RTRM is recommended

5. Negative Forward Bias Test - Switch meter to diode test and put the black (-) meter lead on the J1-9 and and the red meter lead (+) on the same ground from earlier
   • Value should be between 0.5 - 1.2 vdc (~0.5 vdc is most common)
   • Values well below 0.5vdc are a sign of a failing current switch and replacing the RTRM is recommended

RTRM J3-3 Compressor 2 Proving Current Switch Testing

1. Disconnect power to the unit
2. Remove RTRM P3 connector from RTRM J3 connection (located to the right of the thermostat terminals, largest connector on the board)
3. Count to pin 3 on RTRM J3 ( there is a -1 on the board on one end of J3 to denote pin 1)
4. Set meter for resistance (not the ringer) and measure resistance to a good ground (look for the same place that the transformers are bonded to for ground)
   • Value should be ~110k Ω +/- 20k ohms
   • Readings outside this range are a sign of a failed current switch and replacing the RTRM is recommended

5. Positive Forward Bias Test - Switch meter to diode test and put the red (+) lead of the meter on J3-3 and the black meter lead (-) on the same ground from earlier
   • Value should be between 0.5 - 1.2 vdc (~0.5 vdc is most common)
   • Values well below 0.5vdc are a sign of a failed current switch and replacing the RTRM is recommended

6. Negative Forward Bias Test - Switch meter to diode test and put the black (-) meter lead on the J3-3 and and the red meter lead (+) on the same ground from earlier
   • Value should be between 0.5 - 1.2 vdc (~0.5 vdc is most common)
   • Values well below 0.5vdc are a sign of a failing current switch and replacing the RTRM is recommended

RTRM J9-4 Compressor 3 Proving Input

This input is different than the current switch feature for CC1 & CC2, it is an actual input an the RTRM expects to see 24vac here when CC3 is commanded. If 24vac is present here when CC3 is commanded and the RTRM is still producing a compressor proving fault or HPC fault for Compressor 3 and the Compressor 3 troubleshooting has been completed above, it may be necessary to replace the RTRM. 

RTRM Compressor Relay Test

Typically with all the tests above, if the compressor contactor circuit is not open, the contactor will pull in for at least 5 seconds. The RTRM waits for the status (either from the current switch in the RTRM for CC1/2 or 24vac on J9-4 for CC3) before producing the diagnostic and dropping the voltage to the contactor. In cases where all the tests are good above and the compressor contactor is not pulling in, it may point to a bad relay on the RTRM or missing 24vac for the relay. 

To perform the tests below, it is best to have meter leads that will fit into the back of the connector on the RTRM with out damaging the connector or pins. 

Compressor 1 Relay Test

1. Power unit down
2. With power off to the unit, set the meter up for volts AC and connect the black (-) leads to a good ground and the red lead (+) into the back of RTRM P1-10. 
3. Power the unit up and step through Test Mode (See matrix below for Compressor 1 step of test mode)
4. When on the step for Compressor 1 (CC1), 24vac should be present on the meter for at least 5 seconds
   • If no voltage is measured, check meter leads and repeat test
     • If the test fails again, this indicates that the CC1 Relay on the RTRM is potentially failed

5. For CC1 relay, the common power is the same source that powers the RTRM, if the RTRM is powered (LED2 is on or pulsing, the 24vac common is present. 

    

Compressor 2 Relay Test

1. Test for voltage on P3-1, this is the 24vac input for the J3 terminal that is switched through J3-4 to CC2
2. If power is missing here:
   • Precedent units - RTRM J3-1 is powered from the backside of LTB1-3
   • Voyager 2 units - RTRM J3-1 is powered from CTB2 from TNS3
   • Voyager 3 units - RTRM J3-1 is powered from TNS5
3. Power unit down
4. With power off to the unit, set the meter up for volts AC and connect the black (-) leads to a good ground and the red lead (+) into the back of RTRM P3-4. 
5. Power the unit up and step through Test Mode (See matrix below for Compressor 1 step of test mode)
6. When on the step for Compressor 2 (CC2), 24vac should be present on the meter for at least 5 seconds
   • If no voltage is measured, check meter leads and repeat test

7. If the test fails again, this indicates that the CC2 Relay on the RTRM is potentially failed

    

Compressor 3 Relay Test - Voyager 2

1. Test for voltage on P2-10, this is the 24vac input for the J2 terminal that is switched through J2-7 to CC3
   • If power is missing here:
     • Voyager 2 units - RTRM J2-10 is powered from CTB2 from TNS3
2. Power unit down
3. With power off to the unit, set the meter up for volts AC and connect the black (-) leads to a good ground and the red lead (+) into the back of RTRM P2-7. 
4. Power the unit up and step through Test Mode (See matrix below for Compressor 1 step of test mode)
5. When on step 3 for Cool3 (Operates CC3 and CC1 or CC2), 24vac should be present on the meter for at least 5 seconds
   • If no voltage is measured, check meter leads and repeat test
6. If the test fails again, this indicates that the CC3 Relay on the RTRM is potentially failed

Compressor 3 Relay Test - Voyager 3

1. Test for voltage on P2-10, this is the 24vac input for the J2 terminal that is switched through J2-5 to CC3
   • If power is missing here:
     • Voyager 3 units - RTRM J2-10 is powered from TNS1
2. Power unit down
3. With power off to the unit, set the meter up for volts AC and connect the black (-) leads to a good ground and the red lead (+) into the back of RTRM P2-5. 
4. Power the unit up and step through Test Mode (See matrix below for Compressor 1 step of test mode)
5. When on step 3 for Cool3 (Operates CC3 and CC1 or CC2), 24vac should be present on the meter for at least 5 seconds
   • If no voltage is measured, check meter leads and repeat test
6. If the test fails again, this indicates that the CC3 Relay on the RTRM is potentially failed

Cooling Test Mode Matrix

*Single 2-Stage Compressors have CC1 energized for both cooling stages, RTRM J3-4 is energized for the solenoid on 2nd stage

**4-Stage Cooling units have the ability to lead/lag Comp1 & Comp2 to rotate the lead compressor in the tandem set. If RTRM J3-8 is grounded, lead/lag is disabled, cut to enable.

WARNING:

Information in this article is intended for use by individuals possessing adequate backgrounds of electrical and mechanical experience and who comply with all federal, state, and local laws, rules, orders, or regulations related to the installation, service, or repair of a heating or central air conditioning product. Any attempt to install, service, or repair a heating or central air conditioning product may result in personal injury and/or property damage. The manufacturer or seller cannot be responsible for the interpretation of the information contained herein, nor can it assume any liability in connection with its use.