Vailiant eco tech 28 combi

Discussion in 'Eco Talk' started by Mr Sean T, Oct 4, 2021.

  1. Mr Sean T

    Mr Sean T New Member

    Hi, the combi is heating up hot water no problem. When the central heating goes on, the temp is set at 75 but barely getting to 40 and the radiators are lukewarm. Have bled the radiators and there’s no air in the system
  2. Bob Rathbone

    Bob Rathbone Screwfix Select

    Could be the diverter valve sticking, or the CH thermistor, or even something else. What does the user manual advise?
  3. MGW

    MGW Screwfix Select

    Son had this in first house, what was the problem was he had not set the lock shield valves, so first radiator was returning warm water to boiler so boiler thought all radiators satisfied so turned to minimum output. If left long enough one by one it would heat the rooms, and as the TRV closed it would start heating next room, once all rooms heated it would work OK, but took days to finally heat all rooms, and if the programmer turned off boiler it would start again from scratch.

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