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Bosch Greenstar - no heat/DHW

Hi - I have a Bosch Greenstar combi boiler (model #ZWB...) in my apartment that isn't working properly.

I have a contractor doing work in my apartment; yesterday they shortened one of the baseboard radiators, and I haven't had heat/hot water since. The unit heats up and hot water comes out of the tap for a moment, but the temperature on the unit quickly gets up to 199 (not normal - DHW is set to 122) and shuts back off. After the boiler cools down, this cycle repeats.

Today the plumber who originally installed the unit came to take a look, replaced the circulator pump and purged the air out of the system using one of the valves below the unit, but it's still not working. Any idea what might be the issue? Thanks so much.


  • neilc
    neilc Member Posts: 2,714
    pictures of the boiler and the pipes around it,
    do you see any valves closed ?
    known to beat dead horses
  • DZoro
    DZoro Member Posts: 1,048
    You're probably still air locked. The entire system should be purged of air. Pictures would help, boiler room and the shortened base board.