Amana HP won't run on COLD morning

[tperk100]

20 yr old Amana would not run this morning about 6 am. Began t/s by simply turning fan to "on " position. Would not run fan. Went to air handler in attic. Checked volts to blower motor leads. Each of two leads read 120 vac to ground, BUT read ZERO volts to each other, so apparently they both had the same 120 volt phase on them.

After fooling around with motor leads about 9 am the system suddenly came alive and began working with 240 vac across the motor leads. Who knows for sure, but I do not think there were any loose connections that we "fixed" by fooling with them. I am not a REAL HP tech, but I suspect that a component in the compressor unit outside was temporarily "frozen", stuck, or something and was preventing the air handler from operating.

I suspect this will happen again, and am looking for advice on how to find the problem.

Thanks for any assistance.

[HayZee518]

check for a contactor with a mechanical problem. if the contacts welded themselves together they just couldn't un weld them selves. look towards something mechanical.

[dosser]

How cold is the outside air? Does your unit have an outside thermo? Have you looked at the drawing on the inside of the cover? Gas or elec. backup? If furnace is as old as outside unit it may have sequencers if elect. backup. Check the wiring to the fan relay (if an older furnace), look for bad terminals.

[tperk100]

Thanks for the help guys. Here is an update.

The system would not operate again today. The temperature is only about 60 degrees outside. I have discovered that, with the A/C/Heat switch in the OFF position and the fan switch in the ON position, that the fan still would not run. I believe this problem has nothing to do with any outside components.

I went to the attic and tapped on some of the components. One of them looks like a fan relay, and the fan started running. I am still not certain which component is flaky. And the schematic is not readable. I could fix this if I had a schematic.

Any idea of where I can get a schematic for an Amana 1990 air handler?
Model BHEA48T002A, Serial 9007049827

Thanks again for any help you can give me.

[HayZee518]

air handlers I saw on the web all begin with an "A"

[dosser]

The model number you gave is for the heatpump (outside unit) Need the furnace model number.

[tperk100]

Sorry, but this is the model and serial number read directly off of the air handler....not the outside unit.

[dosser]

Well it looks like Amana bundled the air handler info in with the outside unit or part of it anyway, (I hate old Amana units). I have a pdf of the only drawing I could find. It only shows the blower wiring. Since Amana is now part of Goodman, the air handlers now start with "A", but not in your case. Not sure if you want to give out your e-mail, but if so I could send it to you as an attachment. Fan relays are not expensive, and if the thermo was in the "ON" position for a long time, the contacts may have heated up over time and burned open, tapping sometimes makes it work, but not for long. If the relay has been there since 1990, replace it. Pat M.

[tperk100]

Dosser,

Thanks guy. I would LOVE to have that wiring diagram of the air handler. That's what I really need. You can email it to me at
junk1???@accuspec.biz. Please remove the three question marks from the address and it will work. In other works type the address into your email but do not enter the question marks.

Thanks a million!