RT-SVD03G-EN 33
ReliaTel Refrigeration Module (RTRM)
Unit is in OFF mode locally or through TCI/LCI
Heat Pump- Compressors will not run
1. Unit is in the EMERGENCY HEAT mode.
2. If the Compressor Disable circuit or CC1, CC2 circuits create a lockout during heating mode, a
COOL FAIL (pulsing) indication will occur, not a HEAT FAIL (pulsing) indication. See COOL
indications for details.
27½ to 50 Ton Unit Additional Diagnostics (VAV only)
If only one diagnostic is present, refer to that diagnostic. If more than one diagnostic is present,
refer to combination diagnostics such as
COOL + HEAT as appropriate. On a BAYSENS020*, the display will show HEAT FAIL or COOL FAIL
or SERVICE (or an appropriate combination) if a diagnostic is present.
HEAT (YC only)
1. TCO1, TCO2, or TCO3 has opened.
2. IGN Module lockout (see gas heat section for troubleshooting).
3. Supply Air Temperature sensor has failed if configured for Modulating Heat.
COOL
1. Discharge air sensor (DTS) is open, shorted, or has failed.
2. Zone temp input (RTRM J6-1) is open, shorted, or failed during an unoccupied mode. If the unit
has a default mode input (jumper from RTRM J6-2 to RTRM J6-4, a valid zone temp input is
needed for unoccupied heating, MWU and DWU.
3. CC1 or CC2 24 VAC control circuit has opened 3 times during a cooling mode. Check CC1, CC2
coils or any control in series with the coils (winding thermostat, HPC, circuit breaker auxiliary
contacts).
4. LPC 1 or LPC 2 has opened during the 3 minute minimum “on” time during 4 consecutive
compressor starts. Check LPC 1 circuit by measuring voltage from RTRM J1-8 to chassis ground.
Check LPC 2 circuit by measuring voltage from RTRM J3-2 to chassis ground. If 24 VAC is not
present, the circuit is open. 24 VAC should present at these terminals at all times.
SERVICE
The supply fan proving switch (FFS) has failed to open within 40 seconds after the fan starts or
has closed during fan operation.
COOL + SERVICE
1. 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 air pressure.
HEAT + COOL
1. The Emergency Stop input (TB1-5 and TB1-6) is open. Check this input at the RTRM by
measuring voltage from RTRM J1-12 to chassis ground. 24 VAC should be present whenever
the Emergency Stop input is closed.
2. Outdoor air sensor (OAS) input is open, shorted, or has failed.
HEAT + COOL + SERVICE
1. Static Pressure High Duct Static Trip. The static pressure has exceeded 3.5" W.C. three
consecutive times.
2. Ground wire on transducer is open.
27.5-50 Ton VAV Diagnostic
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