Rebuilding Bell & Gossett Zone Valves

Reply

  #1  
Old 12-28-12, 03:29 PM
Member
Thread Starter
Join Date: Dec 2010
Location: USA
Posts: 91
Received 0 Votes on 0 Posts
Rebuilding Bell & Gossett Zone Valves

I just got through rebuilding a few Bell & Gossett zone valves and I thought I would share my experience while it is fresh in my mind. My B&G CTS-7524 zone valves go out about every two years on the main zone and having my boiler for 35 years tells me I have gone through a lot of zone valves and should have replaced them with a more reliable system. That being said, they work better than the valves that came with the system.

Two things usually happen to these zone valves. One is the heat motor burns up and the contacts get dirty. The heat motor is just a power pill that has wax encapsulated in a cylinder which is heated by a 24 VAC coil. This in turn opens the valve and actuates contact closure to provide 24 VAC to a relay which turns on a circulator pump. You can buy the V01370 heat motor assembly from PEX.com for $32 which is a lot cheaper than the $72 they want for a new control unit. Some of the control units had contacts which would not function. I filed them with a point file and that seem to work fine; however, I don't know how long the points will last. They seemed large enough to take the filing.

I also noted that one of the units had contacts which were loose in the housing. After tightening the screws, the unit worked fine. I have asked PEX if the contacts themselves were replaceable. The contacts look as if they could be easily replaced, but I have not received an answer yet.

While I bench tested each of the control units after rebuilding them, I found that occasionally they did not work on the boiler because of either bad contacts or the loose screws. I would recommend testing them on the boiler so you know they are ready to go when you need them.

If I find that the filing of the contacts shortens their useful life or if contacts are available I will post an update.
 
Sponsored Links
  #2  
Old 12-28-12, 04:31 PM
Member
Join Date: Oct 2008
Location: USA
Posts: 2,897
Received 5 Votes on 5 Posts
I wonder if filing the contact points opens up more problems - rough or uneven contact between the points?

You might try fine crocus cloth, pulled between the closed points. You want them to be smooth and mate perfectly.
 
  #3  
Old 12-28-12, 04:57 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 2 Votes on 2 Posts
I filed them with a point file and that seem to work fine; however, I don't know how long the points will last. They seemed large enough to take the filing.
Most relay and switch contacts are plated... abrasive cleaning will removing the plating promoting faster wear and replacement intervals.

Stabilant 22 - the stuff is UBER expensive, but in some cases it solves problems that would otherwise be 'unfixable', like a band selector switch in a Kenwood TS-830 ... or the like...

Amazon.com: Stabilant 22, 5ml Kit Makes 30ml of 22A: Everything Else
 
  #4  
Old 12-28-12, 05:03 PM
Member
Join Date: Oct 2008
Location: USA
Posts: 2,897
Received 5 Votes on 5 Posts
Looks promising. Let me know it you discover a source for less than $38.
 
Reply

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


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