Honeywell Aquastat L8148E

I went to turn on my heat yesterday, and found out that my boiler would not turn on. The burners wouldn't fire. I have water circulating, and the pilot is on.

After a little research, found that the gas valve is supposed to have 24 V coming form the Aquastat...it is 11 V. It is the same 11V at the thermostats as well. 120V coming in....

This has lead me to believe that the transformer is bad in the Aquastat. I did a little searching, and was coming up empty.

Does anybody know where I might be able to just find a replacement transformer for the Aquastat?

 

You won't find a replacement. Aquastats are basically a 'replace only' item. Something about the UL listing... if they are repaired, they no longer are UL listed... and insurance companies don't like that.

Is the transformer hot?

 

Nothing abnormal, at least not that I noticed. I was told by a friend with some experience (via phone) that if the gas valve is not receiving 24V then it will not open, preventing the burners from firing...Everything is status quo up until that the transformer, then only the 11V coming out. I found the whole Aquastat, but thought it may be cheaper to just replace transformer.

Looking at the Aquastat, there is two screws that hold the transformer in, so I figured it may be a replaceable part.

 

Off the record, you didn't hear this from me, you might be able to find a transformer that fits... it just won't say it's for the aquastat...

Check around for best prices on the aquastat... I like

Patriot Supply - Industrial, Commercial & Residential HVAC Parts & Equipment

and their prices are pretty good. You may find other places cheaper if you search around. They ship real fast if it's in stock.

 

I found the relay in town for a relatively cheap price... i was informed that it is not returnable. Does this sound like the problem?

Everything seems to be working with the exception of the burner's firing. The Volts at the Gas Valve are 11. The pilot is on and burning strong. The water is pumping through. Also the juice going to the thermostats, which are the only things coming off of the transformer is 11, as well.

I was told that if the Volts to the Gas Valve are not 24, it will not open...

Thanks for any help you can offer.

 

I can't understand why that transformer wouldn't be hot... Usually if they develop internal shorts and such, they would be.

If you are sure that there's 120 going in, and the transformer is only putting out 11, then it's a reasonably good bet that replacing the a'stat will fix ya up.

Before you replace though, just for the heck of it... disconnect the wires to the gas valve, and measure the transformer again. Then, before you reconnect the gas valve, measure the RESISTANCE of the gas valve terminals.