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Baxi Luna 310fi - Increasing Pressure Issue
Baxi Luna 310fi - combination unit for in floor (Radiant) heating and domestic hot water.
Domestic hot water works perfect no issue.
As soon as in floor heating comes on, pump starts to circulate. As soon as burner lights the pressure shoots up past 3 bar, the Pressure Release valve lets go and hot water comes out. All lights turn off on the unit and heating stops.
My immediate thought is Expansion Vessel... drained the unit and checked it. No pressure. Pumped Expansion Vessel back up to 1.5 Bar, refilled unit and tried again. Exact same problem. I am assuming I need to replace the Expansion Tank but want to make sure that is the fix before doing so as it is a pain in the *** job. Can I confirm somehow that the Expansion Tank is shot. Anything else that could be the problem?
Any thoughts or recommendations? Thanks!!