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The RTRM has the ability to provide the service personnel
with some unit diagnostics and system status information.
Before turning the main power disconnect switch "Off", fol-
low the steps below to check the Unit Control. All diagnos-
tics and system status information stored in the RTRM will
be lost when the main power is turned "Off".
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote discon-
nects before servicing. Follow proper lockout/tagout pro-
cedures to ensure the power can not be inadvertently en-
ergized. Failure to disconnect power before servicing
could result in death or serious injury.
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK HTB1
OR UNIT DISCONNECT SWITCH.
1. Verify that the LED on the RTRM is on. If the LED is on,
go to Step 3.
2. If the LED is not on, verify that 24 VAC is present between
RTRM J1-1 and J1-2. If 24 VAC is present, proceed to
Step 3. If 24 VAC is not present, check the unit main
power supply, check transformer (TNS1) and fuse.
Proceed to Step 3 if necessary.
3. Utilizing "Method 1" or "Method 2" in the "System Status
Diagnostic" section, check the following:
System status
Heating status
Cooling status
If a System failure is indicated, proceed to Step 4. If no
failures are indicated, proceed to Step 5.
4. If a System failure is indicated, recheck Steps 1 and 2. If
the LED is not lit in Step 1, and 24 VAC is present in Step
2, the RTRM has failed. Replace the RTRM.
5. If no failures are indicated, use one of the TEST mode
procedures described in the "Unit Start-Up" section to
start the unit. This procedure will allow you to check all of
the RTRM outputs, and all of the external controls (re-
lays, contactors, etc.) that the RTRM outputs energize, for
each respective mode. Proceed to Step 6.
6. Step the system through all of the available modes and
verify operation of all outputs, controls, and modes. If a
problem in operation is noted in any mode, you may
leave the system in that mode for up to one hour while
troubleshooting. Refer to the sequence of operations for
each mode to assist in verifying proper operation. Make
the necessary repairs and proceed to Steps 7 and 8.
7. If no abnormal operating conditions appear in the test
mode, exit the test mode by turning the power "Off" at the
main power disconnect switch.
8. Refer to the individual component test procedures if other
microelectronic components are suspect.
System Troubleshooting
System Status/Diagnostics
System status and/or diagnostics can be observed at the
ZSM, through ICS, or at the unit by using a DC voltmeter.
The LED on the RTRM module does not indicate whether
diagnostics are present or not. This RTRM LED is an indica-
tor that the RTRM has power, and it pulses during the TEST
mode.
Terminal locations
System Status / Diagnostics checkout procedure (DC
volt meter required)
The method described below to determine unit status or to
see if diagnostics are present assumes the Zone Sensor or
NSB panel is not within sight or close by or is not being
used. If a zone sensor is within sight however, DC readings
need not be taken - just look at the LED or display and go to
STEP 3.
STEP 1: Measure and record DC voltage from J6-6 (com-
mon) to each output: J6-7, J6-8, J6-9, and J6-10.
STEP 2: Using the data below, determine if each output is
ON, OFF, or PULSING.
All voltages are approximate - this is a sensitive circuit, so
the type of voltmeter used, sensor connections etc. may all
slightly affect the reading.
ON = 30VDC if no NSB or ZSM with LED's is connected,
25VDC if NSB panel (BAYSENS019*, BAYSENS020*) is
connected, 2VDC if ZSM w/ LED's (BAYSENS010B,
BAYSENS021B) is connected.
OFF = 0.75 VDC regardless of ZSM / NSB connection
PULSING (DIAGNOSTIC PRESENT) = A distinct pulsing
from 0.75 VDC to 30 VDC will be seen depending on the
type of meter used. Some meters may only pulse from 20 to
30 Volts.
STEP 3: Refer to the data in What Outputs Mean section to
determine course of action.
What Outputs Mean:
HEAT J6-7
COOL J6-8
SYSTEM J6-9
63
On = system is actively heating
Off = system is not actively heating
Pulsing = a diagnostic is present
(see DIAGNOSTICS).
On = system is actively cooling
Off = system is not actively cooling
Pulsing = a diagnostic is present
(see DIAGNOSTICS).
On = RTRM has power
Off = RTRM does not have power or has
failed
Pulsing = unit is in the TEST mode
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Troubleshooting
