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-   -   mcquay rps 30 applied rooftop unit fan fail alarm (

c.gould 04-05-2011 10:20 AM

mcquay rps 30 applied rooftop unit fan fail alarm
any ideas about a fan fail alarm. saf is fine and the air tubes are not clogged and attached properly.

COLDIRON 04-05-2011 01:08 PM

Need a lot more info than that. Could be a lot of things causing it.

c.gould 04-05-2011 01:23 PM

what other info would you need, srry still fairly new in the field. Only thing opperating on the rtu's are the return and supply fans, we cave electric heat in the vavs throughout the building.

COLDIRON 04-05-2011 02:56 PM

Look at the electrical drawings and see what would cause the fan fail circuit alarms, go from there. Keep it simple.

Hubcap626 04-05-2011 07:17 PM

Fan fail is caused from the air flow switch opening. What controller does this have mt2 or 3? I think fan fail needs to occur 3 times within 24 hours for it to shut off and need a manual reset. So it might have happened once and tried to come back on and it did if both fans are currently running.

c.gould 04-06-2011 06:22 AM

It does try 3 times then goes into alarm and shuts down. It is m2 applied rooftop unit controller

Hubcap626 04-06-2011 08:03 AM

Bad air flow switch. Open up door at supply fan and jump out normally open contacts on pc7, the airflow switch. Turn on unit and see if it stays on. Or just put wires on normally closed contacts until you can get a new airflow switch.

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