No announcement yet.

Boiler keeps firing when no demand.

  • If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.
  • Filter
  • Time
  • Show
Clear All
new posts

  • Boiler keeps firing when no demand.

    Appreciate this has been asked on the forums however the answers are specific to the system.

    Potterton Promax SL
    S Plan Room Thermostat, CH interlocked by room thermostat
    HW Storage Tank
    Sealed System

    My boiler is firing up even when there is no demand from the control unit (programmer).
    This used to happen once every hour maybe a year or two ago. Now it's down to circa every 10 minutes. Every 10 minutes the boiler fires up for about 2 minutes.
    I have always disregarded this because I've been advised it is "frost protection" and "normal operation". No, it cannot be surely.
    It was serviced November 2018 but the bloody thing didnt do this naughty behavour so the engineer couldnt remedy it - he claimed

    I'm and electronics engineer but not HVAC or Gas / Domestic so could someone please help guide me through diagnosis.


    Thanks all