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Bosch Tankless Problem

jmph Member Posts: 2
We have a Bosch Tankless Hot Water Heater that performs great in all areas of the house except one...the extra bathroom sink.  I have read some posts on other sites that if there is not enough flow when the sink faucet is turned on the Water Heater will not kick on.  It seems that is true for us.  If we turn on the bathtub faucet at the same time the Water Heater will kick on.  Yet, there are times when the same faucet will produce hot water.

Also, in the master bath..if the toilet is flushed while someone is taking a shower, the hot water diminishes for a few seconds without reduced water flow.

Can anyone help?


  • Alan (California Radiant) Forbes

    You can call Bosch technical support at 1(800)642-3111.  Have the model and serial number ready and be sure you know how to use a multi meter and manometer.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab
  • kcopp
    kcopp Member Posts: 4,443
    its a flow issue.....

    I would try to pull out the flow restrictor in the aerator on the spout.That should help. It may be a 1gpm aerator
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