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Aquastat troubles

lish18lish18 Member Posts: 1
Hello, looking for a little advice. A few weeks ago we had a bad lightning storm. Since then our furnace will not fire, or even attempt to fire. After talking with tech from the company, we have narrowed it down to no power running through the limit to L2 wire in our aquastat. The temp display is also blank on it. We were told to replace the aquastat. However, this is an almost $200 part, and money is a little tight at the moment. Most places charge almost $100 just to agree to come look at it, so I am trying to get as much advice as I can before calling someone in.

I have had a few people tell me that they don't think that the aquastat is the problem, and that the furnace should attempt to fire even if it is bad and that something else is causing the issue. When we open the bleeder, nothing comes out except a few drops, I was told that it's because the pump is not kicking on which is not caused by the aquastat.

The furnace is only about 5 years old.

I don't know that much about furnaces and unfortunately, my fiancé does not either, we have researched and researched things online which does get a little confusing and articles contradict each other. Any advice of things we can check or try would be greatly appreciated.

Thank you!


  • STEVEusaPASTEVEusaPA Member Posts: 4,137
    I'll assume boiler not furnace because you mentioned an aquastat.
    If your dealing with a lightening strike and damaged equipment, you really should pay the money to get a qualified tech to check the components, specifically the safety components of the system.

    You want to make sure the aquastat turns off the burner when a low water situation occurs (if applicable), you want the aquastat to turn off the burner if the boiler temperature reaches the high limit (very important), and you want the primary control to turn off the burn if it senses a loss of flame (EXTREMELY important).
    I wouldn't mess around with it. Just replacing the aquastat and not properly checking the primary and its safeties could result in a very dangerous situation.

    No power to L2 is not a diagnosis, and opening the bleeder is worthless for this situation. It's important that you ignore advice about troubleshooting from non-professionals, specifically people who are not qualified, experienced oil burner technicians. If they want to give you advice, have them recommend someone who they know and trust.

    A full service oil company should be able to perform the proper troubleshooting, and repair. They should check all your safeties, and verify (on their ticket), that your burner is now safe to operate.

    You should also check to see if a breaker popped, and the tech should check to see if your thermal shut off switch (required by code but maybe not installed) is working correctly.

    If it's a verified lightening strike, maybe your homeowner's insurance could help you out.

    All of this is way cheaper than burning down your house, right?
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