Trouble Criterion Of Main Parts - Mitsubishi Electric PAA-A18AA1 Service Manual

13.6. Trouble criterion of main parts

PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
Part name
Return Air
temperature
thermistor
(TH1)
See note below.
Pipe
temperature
thermistor/liquid
(TH2)
Condenser/evaporator
temperature
thermistor
(TH5)
NOTE
If the PAA unit will be or is installed into an unconditioned space, note that air
temperatures in the ductwork (as measured by the return air thermistor) may vary from
the space temperature. Where this variance is large, it can affect the system's ability to
cool the occupied space down to the minimum cooling setpoint or heat up to the maximum
heating setpoint. The following measures can be applied to mitigate the effect of the
temperature variance:
• Insulate the ductwork.
• Use a remote controller option with sensing capability.
• Place the return air thermistor as far away from the furnace as possible, avoiding bypass
ducts, but taking care to ensure that all return duct branches remain upstream of the
thermistor.
• Ensure that the provided mounting bracket is used to position the return air thermistor
well within the air stream.
• Adjust fan in thermal off settings to maintain airflow through the cabinet.
• Install PAC-USSEN00(1|2)FM-1 as the return air sensor, placed into the conditioned
space.
• Use kumo cloud in conjunction with the PAC-USWHS003TH-1 wireless temperature and
humidity sensor.
Specifications are subject to change without notice.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1 and all-
Check method and criterion
Measure the resistance with a tester.
(Part temperature 10° C (50° F) ~ 30° C (86° F)
Refer to section 13.7 Thermistor chart 1 and 2 for thermistor values.
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