Contacts Chattering on Trane Air Handler


  #1  
Old 10-19-11, 08:52 AM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Question Contacts Chattering on Trane Air Handler

My house has a Trane XL Series Weathertron Heat pump with matched air handler approximately 6 years old. I have a Honeywell electronic thermostat which is working well.

A few days ago I turned on the heat and heard a loud sound I thought it was the fan in the air handler. I tried the fan and air conditioning setting they worked and the sound disappeared.

I went into the crawl space removed the covers on the air handler asked my wife to turn on the heat setting. The contactors mounted on the heat side of the Air handler were chattering. There is a 60 Amp circuit breaker mounted close to the contactors with power wires going into the breaker and the Contactors.

There is a five amp fuse near a transformer in the upper left side which I think steps power down to power the thermostat. The 5 amp automotive type fuse looks good. The heat system ran several minutes until I asked my wife to stop it. The contactors were chattering the entire time it ran.

I asked my wife to set the heat to the regular heat setting, and the thermostat to 78 degrees the room temperature was 73 degrees. Several minutes later the unit cycled and the heat came on with the contactors still chattering. I than asked my wife to shut the heat off, reset the thermostat to 75 the room temperature was still 73degrees. The chattering of the contactors continued when we tried the lower temperature setting.

When we switched back to Air conditioning and or fan the contactors don't chatter. Do you know if the transformer, 5 Amp fuse or the circuit breaker mounted near the contactors could have a dead short. The fuse looks ok I have the display on the thermostat.

I don't know what the heat strips look like or how they are mounted. I would appreciate any suggestions on what's causing the contactors on the air handler to chatter when in the heat setting.


Titanic Jobs
C Birchall
 

Last edited by titanicjobs; 10-19-11 at 09:00 AM. Reason: Typo
  #2  
Old 10-19-11, 10:14 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,244
Received 4 Votes on 4 Posts
Something is drawing too much of a load on the low voltage side and causing the contactors to chatter.
 
  #3  
Old 10-20-11, 06:15 AM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Thank you for your response would you reccommend changing the transformer and the 5 amp fuse to start. Would you mind explaining why it's the low voltage side. These units are under a ten year parts warrnty Trane gave a ten year warranty on these models if you purchased them as a pair. Is there any possibility that rust between contact on the 60 amp breaker or anywhere else could cause the chattering.
 
  #4  
Old 10-20-11, 09:14 AM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,244
Received 4 Votes on 4 Posts
It has nothing to do with the transformer or the fuse. It is on the low voltage side because low voltage is what is used to pull the contact in on the contactor. If you have a warranty that would require a contractor to fulfill the warranty. You can't replace any parts and get reimbursed. And they won't just send a part to you that you think is bad. Most likely there is a short in the aux heat low volt circuit.
 
  #5  
Old 10-20-11, 01:20 PM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Thank you again for your time and effort. I was laid off from my job two months ago money has been tight. Last summer the capacitor in the outside unit went bad. I identified the capacitor as bad as the bottom was pushed out(EXPANDED. I'm located in Virginia I called a Trane dealer told them the capacitor was bad I asked if they could bring the part when they came I was told no they would have to troubleshoot. When the tech arrived I had the cover off exposing the capacitor I pointed to the capacitor he said your capacitor is bad. He didn't have the Trane capacitor I was charged 110.00 for him to go and pick it up 3 miles away at the Trane Distributor plus $111.00 for the ten minutes to unplug, unscrew from the bracket and reinstall. I was hoping to narrow down the issue. Would you be able to look at pictures I have a good meter if you could instruct me on how to trace the circuit. I thought I saw power wires coming directly from the 60 Amp breaker to the contactors on the heat side of the air handler.

Chris
 
  #6  
Old 10-20-11, 01:55 PM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 21,110
Received 4 Votes on 4 Posts
Titanic...
Many places carry parts like caps, contactors, thermo switches etc. You could call around to a few supply houses, both electrical and HVAC (do you have a Ferguson up there..or a Grainger) and they will normally sell parts like that to homeowners. Down in Hampton, VA we had an appliance parts place that also sold simple HVAC parts. Could have saved yourself about $170 or so.

I know this doesn't help with the current problem but I ran into a similar thing with my garage door opener just a few weeks ago. A guy was willing to sell me the part, but he would have to charge me a service call plus the cost of the part.
 
  #7  
Old 10-20-11, 02:31 PM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
Gungguy,

Thank you for the input
We do have Fergusons and Granger. I guess they could have cross referenced the Trane part number and given me a compatible capacitor. What does anger me is having a ten year parts warranty on my unit calling a Certified Trane Dealer who not only charges me for the service call but also charges to pick up the warranted part 3 miles away. Can you imagine a Automobile dealer charging you 110.00 dollars to pick up a warranteed alternator.
 
  #8  
Old 10-20-11, 04:29 PM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,244
Received 4 Votes on 4 Posts
the BS part is that a REAL contractor would have had that part on his truck anyway.
 
  #9  
Old 10-20-11, 07:34 PM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
hvactechfw,

I agree aren't Trane dealers required to keep Trane parts just like Ford Dealers are required to keep Ford parts. I was hoping to narrow down my current issue. I have a good meter if you could instruct me on how to trace the circuit find the problem.

Thank you
 
  #10  
Old 10-21-11, 03:57 AM
hvactechfw's Avatar
Member
Join Date: Jan 2011
Posts: 6,244
Received 4 Votes on 4 Posts
remove the w wire on both ends ( stat and air handler) then test for continuity between the wire and ground would be a place to start. I can't really tell what all to check as the every unit is different and it is not right in front of me.

Trane dealers are not required to keep trane parts, but it would be a good idea! However, any capacitor of the correct value could have been put on and then the one removed turned in for warranty. On something as simple and universal as a capacitor there is not a need to use a part from just because a universal part was assigned a trane part number.
 
  #11  
Old 10-21-11, 11:40 AM
T
Member
Thread Starter
Join Date: Oct 2011
Location: USA
Posts: 6
Received 0 Votes on 0 Posts
HVACTECHFW Thanks for the Input
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: