Heat Pump rattles on start up.


  #1  
Old 08-09-10, 10:20 AM
C
Member
Thread Starter
Join Date: Feb 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
Heat Pump rattles on start up.

I have a 14i Trane 2 1/2 Ton Heat Pump that intermittently rattles on start up. It sounds like it is slugging. I checked the voltage to the reversing valve while the unit was not operation and there was no voltage present at the terminals. (I have two other Trane units that were installed at the same time and they have a constant 24 volts @ the reversing valve coil terminals while off and when operating). I lowered the thermostat on the one I am having a problem with and as the HP unit started it sent 24 Volts to the reversing valve coil. When the thermostat reached the set temp. the unit shut down and there was 24 V present.
It is possible I have a bad defrost board? My Thermostat is a Totaline PN 474-011. I went into the advanced settings and they were all okay.
It has a CNT02940 Defrost Board?
 
  #2  
Old 08-09-10, 05:20 PM
Former Member's Avatar
Member
Join Date: May 2006
Location: US
Posts: 734
Upvotes: 0
Received 1 Upvote on 1 Post
doubt it......................... what lead you to believe that it may a reversing valve/defrost type problem? (is there a repair history here?)
 
  #3  
Old 08-10-10, 05:33 AM
C
Member
Thread Starter
Join Date: Feb 2007
Posts: 4
Upvotes: 0
Received 0 Upvotes on 0 Posts
I thought it might be the defrost board because the terminals at the reversing valve solenoid did not have 24 volts. I have two other units that were installed at the same time and they have a constant 24 v to the rev. valve solenoid. The 2 1/2 ton unit I am having a problem with sounds like it slugging or it is jumping back & forth between start and run on startup.
 
  #4  
Old 08-11-10, 09:19 PM
Former Member's Avatar
Member
Join Date: May 2006
Location: US
Posts: 734
Upvotes: 0
Received 1 Upvote on 1 Post
pull a new tstat wire you have a intermittent short in the wires somewhere, it is easier to just pull another one than try to find the short.
 
 

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