Boiler not Firing up for hot water

Discussion in 'Plumbers' Talk' started by SurreyDIYMan, Sep 25, 2021.

  1. SurreyDIYMan

    SurreyDIYMan New Member

    I have a Worcester LPG 30i system boiler which is connected to heating and hot water systems. It's connected to nest thermostats (11 in total) and it has two hot water systems with two cisterns. Both cisterns are controlled by a nest thermostat that control one underfloor heating zone and one cistern. One of the systems won't fire up the boiler for hot water only... it will fire up for underfloor heating. The other thermostat works fine for both water and do the other thermostats for heating. I've replace the nest thermostat and heat link... no change. I've pushed the HW Zone Valve to manual... still not firing up. Any ideas anyone...?
  2. kiaora

    kiaora Screwfix Select

    i assume you have zone valves ?
    if so, checkout if the faulty circuit zone valve has live to the brown wire, if yes, check orange wire,
    if orange live, that's feed to fire boiler
    if brown live, and orange not, faulty zone valve
    if brown not live , no signal from controls

    good luck
  3. Mike83

    Mike83 Screwfix Select

    Probably just a fault zone valve motor.
    Manually opening certain zone valves won’t make the microswitch so only electrical testing will do.

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