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Mike R.
Mike R., Plumber
Category: Plumbing
Satisfied Customers: 2885
Experience:  20 years of plumbing experience, including high end homes and service work.
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I have a Bosch Aquastar 125hx. I am getting very hot water

Customer Question

I have a Bosch Aquastar 125hx. I am getting very hot water (140deg) .
Submitted: 1 year ago.
Category: Plumbing
Customer: replied 1 year ago.
Posted by JustAnswer at customer's request) Hello. I would like to request the following Expert Service(s) from you: Live Phone Call. Let me know if you need more information, or send me the service offer(s) so we can proceed.
Customer: replied 1 year ago.
Cannot control temp no matter where I set the temperature control knob.
Expert:  Daniel Plourde replied 1 year ago.

hi i am dan i can help you with this. first lets start with how old is the heater and when did this first start

Customer: replied 1 year ago.
My water heater is about 9-10yrs old. Its been doing this the last 3 or 4 days.
Expert:  Daniel Plourde replied 1 year ago.

if you turn it all the way down does it produce the same water temp versus it turned all the way up

Customer: replied 1 year ago.
there is no change in temp
Expert:  Daniel Plourde replied 1 year ago.

was the measured outlet temp exactly 140? did you test the temp rise from the heater

Customer: replied 1 year ago.
You still there Dan?
Expert:  Daniel Plourde replied 1 year ago.


Customer: replied 1 year ago.
I'm getting corrosion around gas valve. Temp stays at 140 checked over last couple of days.
I'm going to look into a new unit. I want to cancel all my subscription that I made today.
Expert:  Mike R. replied 1 year ago.

Hi my name is ***** ***** I have been in the plumbing field for 20 years. I will be glad to help you today. If you are certainly going to cancel your subscription that is up to you but I certainly can help with this issue. The problem is very likely a faulty thermistor or blockage in the heat exchanger. The blockage would cause the water to heat longer than it should and overheat the water and the high limit sensor would stop it from heating beyond the max. This issue could very well be solved by flushing the unit. If you are not familiar with how to flush the unit let me know and I will be happy to help with that too.

Expert:  Mike R. replied 1 year ago.

I haven't heard from you. Was the information I provided helpful?