Heating, Air Conditioning, Fridge, HVAC/air sucks out water heater flame


Haven't always had this problem, but it started over a year ago.  When our air conditioner is running and the gas water heater tries to kick in (flame up to heat), it's like the entire flame gets sucked out.  The pilot can be lit and will stay on until it tries to heat up water.  It only goes out if the air conditioner is running at the same time.  Hope you can help!  Tired of re-lighting water heater and afraid to use hot water when air is running!  If you don't have an answer, who do I call to fix the problem?  Plumber or electrician???

Hi Jo, It sounds like a combination of two problems. Your return air duct has a leak in it and the gas valve in the water heater is not operating properly. If your set up is like mine, the water heater is right next to the furnace. When its in A/C mode the blower is running on high speed. That higher speed is just enough to suck the flame out. Check the return duct for any holes or gaps. Especially where the filter is located. Make sure the covers are on the water heater correctly.

If this does not solve the problem, then you need to call heating and cooling company. Tell them you need the gas valve on the water heater checked. They can put a manometer on it and check the gas pressure. It might only take an adjustment to get it working right.

Hope this helps.

Heating, Air Conditioning, Fridge, HVAC

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Jim S.


I can answer questions on gas or electric furnaces, ac units and heat pumps. I don't work on boilers,chillers,or home appliances.


I have been in the HVAC trade for over 35 years. For the past 15 years I have owned my own business. I am semi-retired so I can answer questions in a timely manner.

I attended trade school for 5 years on weekends and evenings. This was very hard to do, but well worth it!

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