Weil McLain CG 4 SPDN fires on zone 1, but not zone 2

Reply

  #1  
Old 10-13-14, 12:43 PM
Member
Thread Starter
Join Date: Feb 2012
Location: USA
Posts: 1
Received 0 Votes on 0 Posts
Weil McLain CG 4 SPDN fires on zone 1, but not zone 2

I have a Weil. McLain CG 4 SPDN boiler with 2 zones controllers by a Taco SR 502 2 zone switching relay and 2 Taco 007 cartridge circulators. These zones feed heat exchangers in 2 air handlers (1 for each zone).

I turned on the heat today, and found that when I raise the temperature on zone 1, the boiler fires as expected and the air handler fan runs. Zone 2, however, makes the same call, the red led lights on the relay, but the boiler does not fire.

I've swapped the relays, but this does not resolve the issue.

Any ideas where to go from here?

Thanks for your help!
 
Sponsored Links
  #2  
Old 10-13-14, 06:41 PM
Member
Join Date: Oct 2008
Location: South Dakota
Posts: 363
Received 0 Votes on 0 Posts
Yeah, it sounds like something is up with the switching relay. Here is a link to the manual:

http://www.taco-hvac.com/uploads/Fil...ry/102-168.pdf

Are the indicator lights on zone 1 behaving the same way as they are for zone 2? When you switch the zone 2 thermostat to "on", does the circ pump for that zone turn on? This would help isolate if the issue is with the switching relay, or if it's another problem.

On another note, be careful working with this switching relay as it switches the 110 volts to run your circulation pumps.
 
  #3  
Old 10-13-14, 07:01 PM
NJT's Avatar
NJT
NJT is offline
Member
Join Date: Oct 2006
Location: USA
Posts: 23,539
Received 3 Votes on 2 Posts
I've swapped the relays, but this does not resolve the issue.
I suspect that the relay which turns the pump on is separate from the relay that switches the 'endswitch' on...
 
  #4  
Old 10-14-14, 05:03 PM
Member
Join Date: Jul 2009
Location: Toronto
Posts: 1,174
Received 0 Votes on 0 Posts
Some of the newer SR502's have a endswitch relay.
If I recall correctly, the relays are DPDT, and one set of contacts switch the 120 VAC load and the other switch the TT output.

You may have a defect in the actual PC board of the SR502.
 
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: