How do I retrieve fail codes from the RTRM when I have a 2-flash fault code?
The RTRM provides certain diagnostic information to the end-user or service technician depending on the type of controls used. Regardless of the controls used, however, a service technician with a DC voltmeter can read the diagnostics at the RTRM as shown below.
Note: When a voltmeter is first applied, allow 2-3 seconds for the reading to stabilize. The actual readings
obtained vary depending on the controls used.
Process:
1. Take the following 4 DC voltage measurements on the J6 connector of the RTRM.
Table 1. Fail Codes
| Measure Point 1 | Measure Point 2 | Voltage Reading = High, Low, or Pulsing | Fail Code | Possible Cause or Next Step |
| J6-6 | J6-7 | Pulsing | Heat |
Gas heat (See ignition module for further fault codes): If any failure occurs such as loss of flame, limit switch trip, flame rollout etc. Supply air temperature sensor failure and unit is CV with modulating heat or modulating reheat. |
| J6-6 | J6-7 | On | Heat | Active Heating |
| J6-6 | J6-7 | Off | Heat | No Heating Call |
| J6-6 | J6-8 | Pulsing | Cool |
High or low pressure switch has opened more than 3 times. Supply air temperature is invalid and unit is VAV or CV with modulating reheat. |
| J6-6 | J6-8 | On | Cool | Active Cooling |
| J6-6 | J6-8 | Off | Cool | No Cooling Call |
| J6-6 | J6-9 | Pulsing | System | Unit in Test Mode |
| J6-6 | J6-9 | On | System | Normal Operation |
| J6-6 | J6-9 | Off | System | RTRM does not have power |
| J6-6 | J6-10 | Pulsing | Service | Fan failure, Fan proving switch issue, freezestat active, smoke detector active, or condensate overflow switch active. |
| J6-6 | J6-10 | On | Service | Clogged filter switch active. |
| J6-6 | J6-10 | Off | Service | Normal Operation |
Table 2. Simultaneous Fail Codes
| Fail Codes | Possible Issue |
| Heat + Cool |
Coil temperature sensor is open or shorted (heat pump only). Unit has failed to defrost properly (see heat pump section for further details). Outdoor air sensor is open or shorted (RTRM version 4.0 or greater). Dehumidification unit - RTOM disconnected or not communicating. RTOM will flash once every few seconds. Emergency stop input is open. Factory installed phase monitor is indicating a fault. Frostat™ input active. Smoke detector active. Entering evaporator temperature failure (on RTDM communication failure (on modulating |
| Cool + Service |
Static pressure transducer output voltage at RTAM J1-3 is less than 0.25VDC. The transducer output is open, shorted, or the transducer is reading a negative supply |
| Heat + Cool + Service |
Static pressure high duct static trip. The static pressure has exceeded 3.5" W.C. three consecutive times. Ground wire on transducer is open. |
ReliaTel Manual - link below
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.