Diagnostics
RT-SVX34F-EN
105
What Outputs Mean:
HEAT J6-7
•
On = system is actively heating
•
Off = system is not actively heating
•
Pulsing = a diagnostic is present (see
DIAGNOSTICS section).
COOL J6-8
•
On = system is actively cooling
•
Off = system is not actively cooling
•
Pulsing = a diagnostic is present (see
DIAGNOSTICS section).
SYSTEM J6-9
•
On = RTRM has power
•
Off = RTRM does not have power or has failed
•
Pulsing = unit is in the TEST mode
SERVICE J6-10
•
On = dirty air filter indication
•
Off = normal operation
•
Pulsing = a diagnostic is present (see
DIAGNOSTICS section).
Note:
Diagnostics for CV/SZ VAV or VAV units are listed
separately. The same diagnostic may have a
different meaning depending on whether the unit
has VAV controls or CV/SZ VAV controls.
Diagnostics (CV and SZ VAV Units Only)
If only one diagnostic is present, refer to that diagnostic
listing below. If more than one diagnostic is present, refer
to combination diagnostics such as COOL + HEAT as
appropriate. On a BAYSENS119*, the display will show
HEAT FAIL or COOL FAIL or SERVICE (or an appropriate
combination) if a diagnostic is present. If the unit is using
a conventional thermostat, diagnostics are still available
by using a DC voltmeter as described above.
HEAT (YC only)
1.
TCO1, TCO2 or TCO3 has opened.
2. IGN Module lockout (see gas heat section for
troubleshooting).
3. Supply Air Temperature has Failed (SZ VAV Only with
Modulating Heat).
COOL
1.
Zone temp input (RTRM J6-1) is open, shorted, or has
failed after the RTRM sensed a valid input. (See note)
Note:
Since CV units may use a conventional thermostat,
the RTRM will not send a diagnostic if a zone sensor
is not attached when power is applied to the unit.
Also, the RTRM ignores a zone sensor if it is
attached to a powered-up unit. (after a brief time-
out). Therefore, always reset power after installing
a mechanical ZSM to terminals RTRM J6-1 through
J6-5.
Note:
All units configured for SZ VAV will blink the Cool
indicator if there is a Zone Temp. input failure
because a valid Zone Temperature reading is
required for all SZ VAV operation.
2. Cooling and heating setpoint inputs are both open,
shorted, or failed, but the unit has a valid zone temp
input.
3. Programmable ZSM (BAYSENS119*) has failed to
communicate after successful communication has
occurred.
4. CC1 or CC2 24 VAC control circuit has opened 3 times
during a cooling mode. Check CC1, CC2 coils or any
controls in series with the coils (winding thermostat,
HPC, circuit breaker auxiliary contacts).
5. 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 be present at these terminals at all times.
6. Discharge air sensor (DTS) input is open, shorted, or
has failed.
SERVICE
1.
The supply fan proving switch (FFS) has failed to close
within 40 seconds after the fan starts or has closed
during fan operation.
HEAT + COOL
1.
The Emergency Stop input (LTB1-5 and LTB1-6) 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.
Smoke Detector input active.
2. Supply Air Temperature Failure on units with
modulating dehumidification
3. Entering Evaporator Temperature Failure on units with
modulating dehumidification.
4. RTDM Communication Failure on units with
modulating dehumidification.
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
BAYSENS119*, the display will show HEAT FAIL or COOL
