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Bosch Combi 151 Very low hot water flow at all faucets

jslone80jslone80 Posts: 4Member
I recently purchased a home with a wall mounted Bosch 151 that was installed in Dec. 2016. My system is on a well. The cold water comes out of the faucet with great pressure but when you switch to using the hot water the flow drastically decreases. i would say by more than half.

Any thoughts on what could be causing my issues?


  • Leon82Leon82 Posts: 653Member
    The flow will be slow untill the unit comes up to temp.

    On a well descaling is absolutely mandatory, multiple times a year if needed. It may have a flow restriction. Does it have isolation/flush valves on the bottom?
  • jslone80jslone80 Posts: 4Member
    No flush valves only the drain and the flow does not change once the water is hot
  • Leon82Leon82 Posts: 653Member
    You need to pump vinegar thru it Or a chemical descaler.

    Flush valves make this easy. Without them you will have to open up the pipe somewhere. I would recommend you install or have someone install them
  • jslone80jslone80 Posts: 4Member
    I will look into having someone install them.
  • Intplm.Intplm. Posts: 1,047Member
    I would make sure that ~ALL~ of your valves are turned on ~ALL~ of the way open first. Than you will be able to tell if descaling is needed. Doing so should help with the flow.

    You should also have your well water tested to see if you need to have your well water treated.

    There are also certain types of descaling filters you can install to help prevent the issue that you are having.
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