Go Back   DIY Chatroom Home Improvement Forum > Home Improvement > HVAC

CLICK HERE AND JOIN OUR COMMUNITY TODAY...IT'S FREE!

Reply
 
Thread Tools Search this Thread Display Modes
Old 08-05-2008, 05:16 PM   #1
Newbie
 
Join Date: Aug 2008
Posts: 5
Share |
Default

Issue with Trane Compressor


I have a Trane 3 1/2 ton residential TTB042D100A unit. It stopped working suddenly and trips the breaker immediately on start. . Never had an issue with it unit now. It is just 8 years old.

I measured the resistance on the compressor, I get 1.0 OHM from start from S-R and S-C and .03 OHM from R - C on the wiring diagram. Is this a shorted compressor? The capacitor looks intact and not bulged.

I don't know what the winding resistance should be, but the fan is around 25 OHMS. It seems shorted to me, but maybe that is what its supposed to be at startup.

Is there any hope for this? (Maybe a start kit?) There may have been a powersurge around the time it died, other things in the house failed as well.

lh12345 is offline   Reply With Quote
Old 08-05-2008, 07:06 PM   #2
Member
 
biggles's Avatar
 
Join Date: Jan 2008
Location: Long Island
Posts: 3,630
Default

Issue with Trane Compressor


how about from each termnial to the copper line see if you read anything might be like putting the leads of the meter together in the ohms reading mode.if it is your shorted winding to compressor body.on the insulated line burp some freon out into your hand or fingers and hold it up to your NOSE if it is a burnt smell or burns your snoz the compressor is burnt out and during the meltdown it cooked the freon also.

biggles is offline   Reply With Quote
Old 08-05-2008, 07:12 PM   #3
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

Issue with Trane Compressor


If you are very comfortable working with electricity:

Turn off the A/C breaker

Put two 4w or 7-1/2w small incandescent lamps in series with the compressor 240v input in series with 120v.

That is, the current comes from the 120v hot lead and goes through a lamp and into one 240v input and comes out the other 240v input and goes through the other lamp and returns to the 120v neutral.

You'll need heavy duty clip leads to do this. Watch out these clip leads don't pop off and land in bad places.

The compressor is now fed by way less than 120v and way less power than it is used to.

I've heard that, in some circles, a modification of this method was a standard test for new wiring.

Both bulbs will probably appear to be full brightness.

With the breakers still off, now your compressor is fed by a sort-of-Current-Source rather than an almost Ideal Voltage Source, and you can measure the AC impedance presented to the line by the compressor by measuring the current through the 120v line and voltage across the compressor.

The desired impedance value should be approximately 240v divided by the locked rotor current listed on the nameplate, probably giving around two ohms impedance.
The advantage over an ohmmeter is that you're measuring reactance and not resistance.

If it is << 2 ohms, power down and start disconnecting things until the short clears.

A simpler version, but not as realistic, is to power the compressor with a doorbell xformer just long enough to measure V and I. No bulbs.

Last edited by Yoyizit; 08-05-2008 at 07:18 PM.
Yoyizit is offline   Reply With Quote
Old 08-05-2008, 07:18 PM   #4
oops, did I do that!
 
Join Date: May 2008
Location: mid michigan
Posts: 290
Default

Issue with Trane Compressor


Your compressor is fried...call the insurance company.
8 Ball is offline   Reply With Quote
Old 08-06-2008, 12:25 PM   #5
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

Issue with Trane Compressor


Quote:
Originally Posted by 8 Ball View Post
Your compressor is fried...call the insurance company.
Talk about making a long story short!
Some of my ideas are half-baked and others haven't even seen the oven.
Yoyizit is offline   Reply With Quote
Old 08-09-2008, 07:37 PM   #6
Newbie
 
Join Date: Aug 2008
Posts: 5
Default

Issue with Trane Compressor


Seems there were issues with low voltage. I got my voltage down very low under load and called the electric company. They have a distribution issue. At the time it failed the voltage may have been low and the motor struggled to start. There were other things in the house that failed at the exact same time. Whatever the case, they are interested in making things right, so thats a good thing.
lh12345 is offline   Reply With Quote
Old 08-10-2008, 08:13 AM   #7
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

Issue with Trane Compressor


Quote:
Originally Posted by lh12345 View Post
Seems there were issues with low voltage. I got my voltage down very low under load and called the electric company. They have a distribution issue. At the time it failed the voltage may have been low and the motor struggled to start. There were other things in the house that failed at the exact same time. Whatever the case, they are interested in making things right, so thats a good thing.
In MD they're "allowed" to go between 114v and 126v.
Yoyizit is offline   Reply With Quote
Old 08-10-2008, 08:48 AM   #8
Newbie
 
Join Date: Aug 2008
Posts: 5
Default

Issue with Trane Compressor


Quote:
Originally Posted by Yoyizit View Post
In MD they're "allowed" to go between 114v and 126v.
How bout 102-113. THe guy measured 112 with the meter off. I get 102 if I turn on all the appliances in the house. Imagine if that big compressor is struggling to start with under 200 volts, maybe less?
lh12345 is offline   Reply With Quote
Old 08-10-2008, 09:09 AM   #9
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

Issue with Trane Compressor


Quote:
Originally Posted by lh12345 View Post
How bout 102-113. THe guy measured 112 with the meter off. I get 102 if I turn on all the appliances in the house. Imagine if that big compressor is struggling to start with under 200 volts, maybe less?
Check the specs on the compressor nameplate for required voltage into it.

Not an electrician, but,
with almost everything turned on in your house:
I guess if it reads lower than 114v x 2 volts at the point where the cables come into your house then the problem is upstream, with PoCo.
Otherwise, it's downstream, in your house, with bad connections or undersized wire.
If some lights get brighter in your house when the compressor tries to start, it could also be a bad neutral connection in your house.
Yoyizit is offline   Reply With Quote
Old 08-10-2008, 09:35 AM   #10
Newbie
 
Join Date: Aug 2008
Posts: 5
Default

Issue with Trane Compressor


Quote:
Originally Posted by Yoyizit View Post
Check the specs on the compressor nameplate for required voltage into it.

Not an electrician, but,
with almost everything turned on in your house:
I guess if it reads lower than 114v x 2 volts at the point where the cables come into your house then the problem is upstream, with PoCo.
Otherwise, it's downstream, in your house, with bad connections or undersized wire.
If some lights get brighter in your house when the compressor tries to start, it could also be a bad neutral connection in your house.
He read 112 with the meter off the box, 221 across both. If the xformer is weak or some other issue, and I load down the house, why can't the voltage drop and be po cos fault? If I turn on all the appliances I can get 108 at the entrance, 103-104 at a running whirlpool that is 150 ft away.
lh12345 is offline   Reply With Quote
Old 08-10-2008, 10:15 AM   #11
Member
 
Join Date: Jul 2008
Location: NW of D.C.
Posts: 5,990
Default

Issue with Trane Compressor


Quote:
Originally Posted by lh12345 View Post
He read 112 with the meter off the box, 221 across both. If the xformer is weak or some other issue, and I load down the house, why can't the voltage drop and be po cos fault? If I turn on all the appliances I can get 108 at the entrance, 103-104 at a running whirlpool that is 150 ft away.
I think it is PoCo's fault, especially if your house is far from the pole transformer.

If they won't help you, you might be able to get a buck-boost xformer wired as a boost, but I think the minimum boost is 12 vac. That might be OK for you.

When Monday comes there will be a lot more advice coming your way.
Yoyizit is offline   Reply With Quote
Old 08-10-2008, 10:21 AM   #12
Newbie
 
Join Date: Aug 2008
Posts: 5
Default

Issue with Trane Compressor


Quote:
Originally Posted by Yoyizit View Post
I think it is PoCo's fault, especially if your house is far from the pole transformer.

If they won't help you, you might be able to get a buck-boost xformer wired as a boost, but I think the minimum boost is 12 vac. That might be OK for you.

When Monday comes there will be a lot more advice coming your way.
200 feet of buried wire
lh12345 is offline   Reply With Quote
Old 08-22-2008, 02:59 PM   #13
Member
 
Join Date: Aug 2008
Posts: 130
Default

Issue with Trane Compressor


I have an older Trane which had a similar problem. The crankcase heater on mine is mounted externally at the bottom of the compressor and it shorted to the compressor case. The unit tripped the breaker immediately every time I tried to reset it. You may have a internally shorted compressor but it wouldn't hurt to check this out as well. Good luck.

kb3ca is offline   Reply With Quote
Reply

Tags
hvac, trane, trips breaker


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Air compressor and framing nailer for DIY ADKstorm Tools 20 11-11-2010 07:38 AM
New Compressor - Wrong Charge? shayneb HVAC 4 08-23-2008 08:13 AM
air compressor - dangerous???? reds_21 General DIY Discussions 23 04-25-2008 10:17 PM
Fridge compressor convert to air compressor? jogr Appliances 1 04-24-2008 01:10 PM
Air Compressor Timer 69-er Electrical 7 10-02-2007 03:40 PM




Top of Page | View New Posts

Copyright © 2003-2014 Escalate Media. All Rights Reserved.