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AquaStar 125B NG continues heating water when no demand

My AquaStart 125B NG continues heating the water when all the hot water facets are turned off in my house. It is like the value gets stuck on. I do not have a circulating pump. I have to manually turn the switch off on the unit to stop it from heating the water to reset it.

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I found the manufactures website and read this specific tech bulletin. I will be replacing or repairing my water value soon.

http://www.boschhotwater.com/Portals/7/TechBulletins/TWH-G1-25_Water_valve_rebuild_B.pdf

The bulletin said the following:
If the burners fail to go off immediately when the
water is turned off, usually due to mineralization in
the water valve on older heaters. To test for this
possiblilty, run hot water at a faucet, then shut off
the cold inlet supply and observe if the burners go
off immediately. If they do not the Aquastar will
overheat and shut down on safety depending on
the delay.

Posted on Jan 12, 2009

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