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burnselk 02-05-2010 09:48 AM

Carrier Heat Pump stopped working
I'm having problems with my 1984 Carrier Model: 38QB030300 SN: U402518 2.5 ton Heat Pump. It acts like it's going to start.......buzzing and humming......but in a couple of minutes it just shuts down. It did this off and on the other day until I pulled the power so I could check things out. I need a new system but I'd like to fix this one so it will serve me a while longer.

What could be the problem.......the fan motor, the capacitor, or a relay? I was told to check the reset button but could not find one? I currently have the power off, the capacitor out, and the motor/fan out trying to get them checked out.

How would you suggest I get the capacitor and fan motor checked? I put a multimeter on the three connection tabs and I don't think it's shorted out.....and the meter needle moves up slightly (this meter only has one setting for resistance (1K ohm) then it drops back quickly on ever conceivable way to check it. I'm beginning to think it's the motor since this motor "frooze up" on me about 4 months ago.......I finally got it going again after oiling it good. The fan wouldn't turn before I oiled it really good and kept turning the fan blades.

Does anyone have any suggestions, I'd like to get it myself (with good parts of course) if at all possible. I just need to know (without buying the wrong parts) what part I need. I'm very cautious with electricity so you don't need to warn me about that. I'm a has been electrician but most all of my training/experience was working on aircraft. But I'm handy enough to do this..........with your help of course.

Running on Aux heat (electric indoor furnace) is probably costing me bunches. I was told by a local HVAC company that I could do that until I could either repair the old one or buy a completely new system........which I plan to do later this year.......if it's the Lord's will.

Thanks in advance for any help you can throw my way.

Marty S. 02-05-2010 06:06 PM

Have 24 volts to the contactor windings and 220 going to the compressor and fan? If so replace the capacitor. A weak one will still load and discharge but not have enough umph. It is 26 years old so I wouldn't put much money in it.

burnselk 02-06-2010 12:30 AM


Originally Posted by Marty S. (Post 395394)
Have 24 volts to the contactor windings and 220 going to the compressor and fan?

Where specifically do I check for these two voltages?


If so replace the capacitor.
I can't read the size of the's rusty right where I need to see the farads. Who could tell me what size capacitor I need? Is there a way to determine the size with a multimeter that has a farad setting? Or short of that, is there a standard size for a 1/4 hp 230 volt motor?


It is 26 years old so I wouldn't put much money in it.
Would you put $200+ in a new motor and the cost of a capacitor? What do you consider too much money?

An entirely new HVAC system is going to cost me around $8,000 it appears.

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