by sparx »
Mon Dec 27, 2010 5:20 pm
Hi, easiest way to see if stat faulty is to temp. replace it with a standard light switch, turn on and boiler 'fires' turn off and boiler stops.
If this doesn't work the fault is elsewhere in the system.
Isolate & note connections before disconnecting 'stat and put Neutral (if there) in a spare connector and 'stats other 2 wires to C&L1 of switch.
Is this a combi or are there motorised valve(s) in circuit?
more info would help diagnosis