Mistral oil boiler not working properly

Lew · Post by **Lew** » Mon Jan 02, 2023 4:59 pm

I had a new Mistral ODC-3 external oil boiler installed last year. Today I moved a few radiator pipes so I drained the system by using the valve on the bottom of the hot water reservoir. Finished the job, filled the system again, bled it at the radiators, but the boiler isn't working properly at the minute. When I first switched it on, there was a lot of gurgling, but the boiler fired. After a while the high limit light came on and it stopped burning. The radiator flow got very hot for a bit .. but I never had any hot water from the tap - that is stone cold. Any ideas? Have I got an airlock in the boiler or something?

ericmark · Post by **ericmark** » Mon Jan 02, 2023 5:15 pm

It seems very likely an air lock, need to bleed each radiator twice, once with only lock shield open, and once with only TRV open so both feed and return is bled.