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Why does the pilot lights up but it will not stay on my

Customer Question
Why does the pilot...

Why does the pilot lights up but it will not stay on my Bosch tankless water heater??

Contractor's Assistant: Can you guesstimate how old your Bosch is? And just to clarify, what's the exact model?

8 years old model aq 125 b

Contractor's Assistant: Do you plan on doing the work yourself?

I think so

Submitted: 11 months ago.Category: Plumbing
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Answered in 22 hours by:
8/7/2017
Plumber: Phil, Mechanical Engineer. replied 11 months ago
Phil
Phil, Mechanical Engineer.
Category: Plumbing
Satisfied Customers: 9,693
Experience: Retired mech. contractor, shop owner, 51 yrs experience.
Verified

Greetings, if the pilot comes on, and then goes off within 5 seconds the problem is with the flame sensor rod or the printed circuit board, most likely the flame sensor rod, cleaning it will often solve the problem

If the pilot light stays on for longer than 90 seconds it is likely that water heaters heat exchanger needs o be acid flushed.

Let me know, we can go from there

.

Important note about RATING my work:

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All I ask is please select the***RATING LINK***at the top of your page, that is the only way I am credited through the site. Rating does not affect your charges nor ability to refund if not satisfied.

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If you need to be coached through a full diagnosis/repair,and wiring etc. for up to two days, and wish to be trained to use test instruments...... that goes well beyond' Just a simple Answer' of course, and goes beyond what most other experts here offer.....rate my simple answer so far positively.. and I will deliver that training and coaching to you All on the same dime so to speak.

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Lacking a positive rating I can spend days helping a person at my own expense and loose my shirt,shorts and socks on the deal.

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Attach a close up photo of the wiring diagram glued to the inside of the blower access door and I will mark it up with troubleshooting instructions then follow up with step by step training and coaching until you have a solution.

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Photo must be exceedingly well focused. Use the 'add files' link next to your send button to get the photo to me.

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