Trane Modu manual WSM Mixed AirTemp Sensor Fail, Water Flow Fail

Diagnostic

Troubleshooting Diagnostics

W

WSM Communications Fail Problem: The RTM has lost communication with the WSM. Check: Field/unit wiring between RTM and WSM.

Reason for Diagnostic: The RTM has lost communication with the WSM.

UCM’s Reaction:The UCM will react as if a freezestat has occurred by issuing:

•An “All Heat On” or “Mod Output Full Open” request to “Heat Control”

•A “Fan off” request to “Supply Fan Control”

•A “Close Damper” request to

“Economizer Actuator Control”

•The water pump to turn on and position all water valves to provide maximum flow through all water source heat exchangers

•Disables preheat function if WSM Mixed AirTemp Sensor is selected as Preheat Sensor

Reset Required: An automatic reset occurs after one complete set of IPC packets is received.

WSM Mixed AirTemp Sensor Fail

b. Activation Conditions: temperature < - 50 F or temperature > 209 F, and sensor is selected for use by “Water Side Economizer Temperature Enable Function” or “Preheat Function”

c.Time to React: 10 sec <T < 20 sec

e. Actions to be Initiated: “Water Side Economizer Temperature Enable Function” uses Supply Air Cooling Setpoint instead of Mixed Air Temperature. If Mixed Air Temperature is being used for “Preheat Function”, issue a “Disable” request to “Preheat Function”.

f. Reset: An automatic reset occurs after the Mixed AirTemp. input returns to within range continuously for 10 seconds.

Water Flow Fail

a. Data used (module,packet,byte,bit): WSM, 01,19,05

b. Activation Conditions: The water flow input is detected open ;

1.at the end of precool water flow initiation state, or

2.continuously for five minutes while:

·water side economizer is open 100%,

·presetting of a Head Pressure Valve, or

·demand for mechanical cooling.

Unit must be: a. configured with water cooled condenser and/or water economizer and b. have water flow switch installed.

c.Time to React: immediate

e. Actions to be Initiated: A “Lockout All Ckts” request is issued to the “Compressor Staging Function”

f. Reset: An automatic reset occurs after the Water Flow input returns to within range continuously for 3 seconds, the water pump is requested OFF, or the water flow switch becomes not installed.

Z

Zone Cool Setpoint Failure Problem: The occupied zone cooling setpoint is out of range.

Reason for Diagnostic: The input designated as occupied zone cooling setpoint source is out of range (temp. < 45 F or temp > 94 F).

UCM’s Reaction:The active occupied zone cooling setpoint reverts to the default occupied zone cooling setpoint.

Reset Required: (PAR) an automatic reset occurs after the designated occupied zone CSP input returns to its allowable range for 10 continuous seconds, or after a different valid occupied zone CSP selection source is user-defined.

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