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Author Topic: Lost thermosiphon?  (Read 460 times)


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Lost thermosiphon?
« on: May 06, 2018, 04:57:21 PM »

Hey everyone it's been a while since I've been around. Looking for some help with a problem I'm having. I've got a sidearm hooked up to my 40 gallon hot water heater and it has always worked great. Friday a windstorm took our power out and it was off for a little over 24 hours. When the power came back on and everything was up and running I had hot water as usual. This morning my wife wanted to take a shower and the water was ice cold. Stove was up to temp so that wasnt the issue. I felt the pipe coming out of the top of the sidearm that runs into the hot water heater and it was cool to the touch. So I turned the switch on so the elements would come on and we would have hot water again. What would have caused the thermosiphon to stop, and more importantly how do I fix it? Thanks for any help.
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Re: Lost thermosiphon?
« Reply #1 on: May 06, 2018, 06:21:42 PM »

Is hot water flowing from the owb to the house?
Maybe the pump air locked or started cavitating when the power came back on?
« Last Edit: May 06, 2018, 06:24:06 PM by Pointblank »
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Re: Lost thermosiphon?
« Reply #2 on: May 06, 2018, 11:02:46 PM »

If the pump is running and the hot boiler water is flowing through the sidearm then it might be airlocked.
If you don't have a bleader valve at the top of the sidearm, open the relief valve to flush any trapped air out. (this is assuming the relief is in a tee at the top of the sidearm)