My boiler kicks in when the thermostat asks it to, but when my room thermostat asks the boiler to fire up, nothing happens.

My room thermostat clicks on, and lights up so I think it can tell the temperature of the room.

Please can anyone help with my problem?

Boiler: ideal classic lxff
Room thermostat: horstmann HRT 2


1 Answer 1


The room thermostat does not control the boiler directly. Instead, it controls a circulating pump that draws heat from the boiler and delivers it to the radiator(s) in the room. It is the removal of heat that subsequently causes the boiler to fire, when its thermostat indicates that its internal temperature has dropped because of the heat removal.

It sounds like either the circulating pump or the relay that controls it has gone bad and needs to be replaced.

  • 1
    ...or the wire in-between the two.
    – Ecnerwal
    Apr 16, 2015 at 14:35

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