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John, Home Appliance Technician
Category: Appliance
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Experience:  Appliance repair business owner for over 43 years.
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HI, I have a Bosch tankless water heater. When it works it

Resolved Question:

HI, I have a Bosch tankless water heater (250 SX). When it works it works great, the proplem is keeping it working. I constantly have to reset the heater beacuse it will go into a mode where the display falshes P2 or E0, the manual says this means the incoming water is too cold. I can see this in winter, but it does this in summer as well. Also it will work fine for a week then stop, I'll go and restart the unit 10 to 20 times then it will start working again. I've had people tell me that the problem is that it isn't vented properly or that the incoming gas supply is not sufficiant. They both seem logical, but that doesn't explain why it works great for weeks at a time, then will stop and need to be reset 3 times in one week.

Thanks for any help.


Submitted: 8 years ago.
Category: Appliance
Expert:  John replied 8 years ago.
hi. thanks for the question. I think the problem is with the venting. the pilot light gets blown out . I have a propane heater that does the same thing. the wind is the problem and venting .thanks the appliance doc
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Customer: replied 8 years ago.

HI and thanks for you help.


I could see the wind being a problem if it did this consistantly on windy days, but the weather doesn't seem to have an effect. Also this unit does not have a pilot light, it has the electronic ignition.


I was told by a Bosch tech that I need to hard pipe the gas all the way to the heater and not use the usual flex hose as you would on any other gas appliance. That doesn't seem like a good idea to me and I'm not sure if that is even to code.


Should I try this as well as change the venting layout?