furnace blowing out the filter. (updated)

[newtekbuzz]

I am posting this here because I do not have the brand with me.. im at work. 1996 holly park dbl wide. i noticed that the air was running a lot yesterday but house was not cooling down... felt the vent and nothing was coming out.... went outside and AC was running.. went to furnace and it was blowing air back out thru the filters.. shut it down and 4 hrs later kicked it back on and it worked. well.... its doing it again and wont seem to fix by the same method. any ideas on what this could be?? sorry for the lack of information.... will post brand make when I get home.

THanks for any help

****model is a intertherm, #mgha-077abfc-05****

Tim

[Robert]

Hi Tim,


Replace the run capacitor mounted on the blower housing side or top.


If it does it again after that, call an hvac tech out to diagnose the problem.



Thanks,
Robert

[newtekbuzz]

Hi robert,

So just ask for a run cap. For that model and its that easy?

Thanks

[Robert]

Hi,


Look on the run cap for the mfd and volt rating.


As an example,,,,,,,, 5mfd / 370V .


See what the mfd and V rating is and get a matching run cap.


Then it may be as easy as that, but not always.



Thanks,
Robert

[newtekbuzz]

Well, after I got the new cap installed, the transformer went. Tech friend of mine came by.
We put new trans on and they got hot and blew after a few. The fan on the unit wants to run regardless of thermostat.
I have also replaced the relay. As of right now unit has new run cap, trans., relay.
There are two other little things that have not been replaced. I was told the are for heater side, not for ac. Parts could stillbe bad though.
Will have tech come back tomorrow...... Right now ac won't kick on and blower fan won't turn off via thermostat.
Any ideas at all?
Thanks,
Tim

[Robert]

Did it just suddenly start this ?


Is this the first summer with this unit ?




Thanks,
Robert

[newtekbuzz]

It started sat. With blower running backwards.
The unit is 13 years old.

[Robert]

Hi Tim,


Sounds like a short in low voltage circuit going to blower motor. Look for bare spots on wires where they can touch other parts or metal.


May have to disconnect at transformer and follow circuit reconnecting one section/part at a time to locate short.



Thanks,
Robert