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John, restaurant equipment technician
Category: Appliance
Satisfied Customers: 2136
Experience:  25+ years experience. I'm now employed by a commercial cooking equipment service company
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I have a Bosch AQ 125x tankless water heater. The unit was

Resolved Question:

I have a Bosch AQ 125x tankless water heater. The unit was exposed to cold temperatures and froze. Now the the pilot light which is normally off, until water is flowing through the system, will stay on for about 20 sec, die out, then spark back on. It will repeat this cycle endlessly whether or not hot water is being used.
Submitted: 5 years ago.
Category: Appliance
Expert:  John replied 5 years ago.

It's likely that the control board was damaged during the freeze. In that case, it will need to be replaced. You can find the part information at

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Customer: replied 5 years ago.
Thanks John. Looking at the parts diagram, there is a control box shown, not a control board. Is this what you are talking about? Where can I order one?
Expert:  John replied 5 years ago.
Yes. You should find a dealer locator menu at the website.
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