Laars Minitherm JVS banging/knocking

theStudent

Hi,



Have 4 years old Laars Minitherm JVS boiler. recently it started to make banging/knocking sounds. It starts, works for about 15 minutes, temperature goes to about 165-170 degrees, then knocking/banging starts, I see pressure spike on pressure gauge and water spill through spirovent (it is on primary loop) occurs. Primary loop circulator was replaced by a plumber, but it did not help. Any thoughts? Thank you.

hot_rod

a flow issue

Is it the correct size pump? Air purged out? Could be the HX is plugging up inside the tubes, it may need a chemical flush. Measure the temperature rise from supply to return.

theStudent

Thank you

Thank you, you were right. Yesterday we checked everything and it appears that the problem was with primary circulator loose wire. So far it works fine. Thank you very much again.

nicholas bonham-carter

Thanks for the update

It's nice to see the final result of the advice given here!--NBC