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Billy, Technician
Category: Pool and Spa
Satisfied Customers: 22003
Experience:  Licensed in Hydronics and Boilers
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I have a raypak millivolt that keeps blowing rollout fuse

Customer Question

i have a raypak millivolt that keeps blowing rollout fuse but he flame doesn't appear to be rolling out
JA: I'll do all I can to help. How long have you been dealing with this?
Customer: 2 days ,happened after i changed seized pump
JA: Do you plan on doing the work yourself?
Customer: yes
JA: Anything else we should know to help you best?
Customer: is it normal that the pressure increased with new pump
Submitted: 2 months ago.
Category: Pool and Spa
Expert:  Billy replied 2 months ago.


My name is Billy.

First - yes it is common to see better pressure with new pump assembly.

Now as far as roll out.....this means partially plugged exchanger or flue which is backing up heat. It doesnt take flame roll out, just excessive heat.

If you replaced already...then you still have a heat issue rolling back.

It can only be obstruction or overfired...


Customer: replied 2 months ago.
remove header and try to clean out?
Expert:  Billy replied 2 months ago.

Correct. This is especially prevalent on LP units.

You will need to remove the header and blow back or rod out exchanger

Expert:  Billy replied 2 months ago.

do not cheat by moving the roll out switch...this is an important safety device there for a reason....

Customer: replied 2 months ago.
i jumped it just to see if it rolled out which it did not
Expert:  Billy replied 2 months ago.

Yes, it will not be so much flame rolling back...but heat that is impeded through the exchanger. Sounds like you are partially plugged....soot rust, nest....I have found them all.

A good air compressor, shop vacuum and brush + patience and you should be fine.

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