SCXF-SVX01Q-EN
105
Category
Diagnostic
G
GBAS 0-5 VDC Module Communication Failure
Problem
The RTM has lost communication with the GBAS module.
Check
Field/unit wiring between RTM and GBAS.
Reason for
Diagnostic
The RTM has lost communication with the GBAS module.
Reaction
The UCM will initiate the following actions;
•
If the demand limit input was closed prior to the communications loss, then the demand limit commands issued to the heat
operation function (if applicable) and the compressor staging/chilled water cooling function will be cancelled.
•
If any of the GBAS setpoint control parameters are the HI-selected setpoint sources, then those setpoints will revert to the
default HI setpoints.
•
Any active GBAS output control parameters will be ignored.
•
A failsafe function in the GBAS module will cause all GBAS outputs to be zeroed and de-energized.
Reset
Required
(PAR) An automatic reset occurs after communication has been restored.
H
Heat Failure
Problem
The heat has failed. (Electric heat unit)Typically, this is because the electric heat section became too hot.
Reason for
Diagnostic
The heat fail input on the heat module was closed:
•
For more than 80 seconds,
•
For ten consecutive occurrences (each lasting five seconds or more) within a 210 second period.
Controls
Reaction
A n information only diagnostic is set.
Reset
Required
(INFO) An automatic reset occurs after the heat fail input remains open for 210 seconds continuously.
Heat Module Auxiliary Temperature Sensor Fail
Problem
The heat mod aux temp sensor input is out of range.
Check
Sensor resistance should be between 830 ohms (200°F) and 345.7 ohms (-40°F). If so, check field/unit wiring between sensor
and heat module.
Reason for
Diagnostic
At least one enabled unit function has the heat module auxiliary temperature input designated as its sensor, and the unit is
reading a signal that is out of range for this input (temp < -55°F or temp > 209°F).
Controls
Reaction
The functions that designated the heat module auxiliary temperature input as their input are disabled.
Reset
Required
(PAR) An automatic reset occurs after the heat module auxiliary temperature input returns to its allowable range for 10
seconds.
Heat Module Comm Failure
Problem
The RTM has lost communication with the heat module.
Check
Check field/unit wiring between RTM and heat module.
Reason for
Diagnostic
The RTM has lost communication with the heat module.
Controls
Reaction
•
An “all heat off” request is sent to the heat operation function.
•
If the unit has staged gas or electric heat, all heat module outputs will be zeroed and de-energized.
•
If the unit has hydronic heat or chilled water installed, the unit will turn off the supply fan and close the outside air damper
upon the occurrence of a heat module comm failure. A fail-safe function in the heat module will cause all water valves to be
set to 100% to provide full water flow. Unless used for switching purposes (air handlers with chilled water and mod gas, or
chilled water and hydronic heat) all binary outputs will be de-energized.
Summary of Contents for IntelliPak SCRF 25
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