Startup Capacitors - http://www.hvacmechanic.com/ Forums

Original message

jameslee

24.123.204.121

"Startup Capacitors" , posted Wed 25 Jun 18:29

I have a Trane Weathertron XE 900 heat pump. The startup capacitors for the blower fan and the compressor are getting weak. They look like a plug and play situation. Should I attempt this myself and if so where can I find the capacitor parts.

Model number TWD736B100A0

Thanks,
James

Replies:

Freon

68.220.5.87

"Re(1):Startup Capacitors" , posted Thu 26 Jun 10:44

Replacing capacitors is easy and they are inexpensive. If you're talking about the outdoor condenser unit you will find there is usually one RUN capacitor that is a dual capacitor meaning it is 2 capacitors in one cylindrical case. Be sure all power is off to the condenser (pull the 240 volt disconnect), and as you remove the wires to the three terminals of the capacitor, MARK THEM CAREFULLY so you can reconnect eaasily. Take the old cap to an HVAC store and get an IDENTICAL one in terms of microfarad rating. The voltage can be equal to or greater than the current cap's voltage rating.

Jameslee

24.123.204.121

"Re(2):Startup Capacitors" , posted Thu 26 Jun 11:10:

Thanks Freon,

There are actually two capacitors, one for the fan and one for the compressor.

I certainly want to be safe doing this. Do I need to discharge any remaining power in the capacitors to prevent getting shocked?

James

[this message was edited by Jameslee on Thu 26 Jun 11:11]

Freon

68.220.40.94

"Re(3):Startup Capacitors" , posted Thu 26 Jun 13:27

You can discharge them but a better way is to wait 10 to 15 minutes after pulling the disconnect and then discharge them. You will find no residual energy by then and sparks are not what you want.

Be sure to mark which cap goes with which wires. If there are two caps, they will have different microfarad ratings... don't mix'em up. Also double check you have two single run capacitors... there will only be two leads. A dual capacitor will have three terminals marked, HERM, FAN and COM. The only reason I mention this is to be sure you're not replacing what could be a hard start capacitor (sometimes called superboost).

theduke03

24.250.18.179

"Re(1):Startup Capacitors" , posted Wed 25 Jun 19:25

How weak are they?

"My dad was the most feared furnace fighter in Northern Indiana."

jameslee

24.123.204.121

"Re(2):Startup Capacitors" , posted Wed 25 Jun 20:26

Thanks for response.

I am not sure, I had a system maintenance done today. Everything checked out OK but the technician mentioned it. He was in there with a volt meter and seem competent. The downside is they wanted $180 each to replace! He said they just plugged in when I question how they were connected. Seems expensive for a capacitor.

Any thoughts,

Thanks in advance,

James

jerrync

65.162.59.89

"Re(3):Startup Capacitors" , posted Thu 26 Jun 16:08

There is probably nothing wrong with the capacitor. That is generally a way to make a sell. The posted uf can usually go 10% either way before I would replace.

theduke03

24.250.18.179

"Re(3):Startup Capacitors" , posted Wed 25 Jun 20:43

That smells a bit fishy to me. Are blower and compressor running OK? If so then you should probably not buy anything. Or you can get something like this meter below to measure microfarads and test the capacitors yourself.
This picture is brought to you by the good graces of Houston204.

"My dad was the most feared furnace fighter in Northern Indiana."