Burnham Independence...chattering relay. What gives?

JohnNY

Just got my third "chattering relay" in about a month. All newer boilers. Does anyone know what causes this? I'm on my way to go check it out but it seems more common lately yet it's such simple wiring.

Zman

What are you using for a switch?
Does it chatter if you jump the switch?

Jamie Hall

Check all your voltages, @JohnNY -- most times when I've hit a chattering relay it's because the voltage isn't quite up to what it should be when the relay is trying to draw in. It can be a transient thing.

And it may well be new, and real -- it's possible that the relay was changed and requires a slightly higher voltage or has a higher pull in current draw.

unclejohn

The power goes into the low water cut off then through the limit and then to the relay term.#3 and waits for the tstat to call. When that happens power goes through relay via term. #1 to damper and then to spark ign. The only thing talking to the relay is the tstat.

Jamie Hall

Which leads me to wonder -- is there any relationship to the thermostat? Or to look at it another way -- if you short the thermostat wires, does the relay still chatter?

ChrisJ

Did you meter out the relay? Is it getting a respectable voltage to the coil? Is the coil rated for AC?

JUGHNE

I would jumper the t-sat connections at the boiler.....also with the t-stat calling, IIWM, put an ohm meter on the disconnected R-W at the boiler. Something there could be substandard.

Or when the vent damper engages it drops the 24V so much that the relay drops out, recovers and tries again.

Zman

Jamie Hall said:

Which leads me to wonder -- is there any relationship to the thermostat? Or to look at it another way -- if you short the thermostat wires, does the relay still chatter?

That is what I meant by switch. Is the t-stat wired to the boiler or is a zone valve, zone controller?

ratio

Yeah, check for low voltage, especially when lots of loads are trying to start; but also look carefully at any electronic stats, the kind with SCRs instead of relays. You'll know them because they don't click. Electrically, they're two back-to-back diodes that can be turned on & off. What I've found once or twice is one of the diodes failed shorted, resulting in pulsing DC being applied to the contactor. Sounded horrible!

Danny Scully

Do you have a wire tie straped around it @JohnNY?

JohnNY

Thanks a bunch, guys. This one turned out to be the insulation on one of the wires to the spill switch was torn and it was making contact with the boiler jacket. Oddball problem. Caught it and spliced it back together.
Annoying....