Help with baseboard heaters/thermostat please.

[Jlggomez]

Hello, newbie here and thank you all very much in advance.

I have two 8’ electric baseboard heaters in my living room. Both are on the same breaker and both are controlled by one old Honeywell T87F low voltage thermostat and a White-Rogers relay box in the basement. One of the heaters will not turn off even when the temp is lowered all the way on the thermostat. The other heater operates normally. Logic (?) tells me that the problem has to be the relay and not the thermostat. Am I on the right track in trouble shooting this? Any thoughts and/or suggestions would be very appreciated. Thanks a lot.

 

[James]

I would be looking in the direction of that relay box to continue fault finding.

Sounds like it could well be a failed relay.

 

[Jlggomez]

Thank you for your response. Do you think spray contact cleaner sprayed on the relay contacts would help? Thanks.

 

[James]

No, a replacement is the way forward, sounds like contacts may have welded closed.

 

[Jlggomez]

Thank you; very helpful and makes sense. Newbie question: then why does one of the baseboard heaters controlled by the same relay work properly and not the other?

 

[James]

It may not be the same relay, you mentioned a relay box.
There could be 2 relays inside it, or there may be one relay with multiple contacts.

A photo of the inside of said box is the only way to tell what the actual switching arrangement is.

 

[Jlggomez]

It may not be the same relay, you mentioned a relay box.
There could be 2 relays inside it, or there may be one relay with multiple contacts.

A photo of the inside of said box is the only way to tell what the actual switching arrangement is.

What do you think? Thanks for your time.

 

[Jlggomez]

A follow up that may be of help to someone.

Upon closer inspection I noticed a fair amount of corrosion on one of the electrical contact points of the lower relay (pic). The corrosion seemed to be making the gap very very narrow, possibly closing it. I sprayed Deoxit on all the electrical contact points of both relays and on the one with corrosion I also used a thin file to file off any corrosion. This seemed to open up the gap a bit. Well what do you know?! Both baseboard heaters are now shuttling on/off correctly and consistently. It’s been five days. Hopefully it will stay that way.

Thanks to all for the help.