Hi I’ve got a Glowworm swift flow 80 gas combi boiler, The pilot light went out, installed a new thermocouple didn’t solve the problem ? Does any one know what ohms reading I should get across the gas valve? As when this drops to around 7 ohms the gas valve trips out, just wondering if I’ve been sold the wrong thermocouple. I can get the boiler fired up with hot water working fine but when boiler is in idle, I put my meter across thermocouple conection though heating high limit cut off stat and sometimes the ohms reading drops to 7 ohms and trip the gas valve ??(when boiler in run state ohms reading are above 10 ohms).

paul perry (spark), February 2007

check where thermocouple enters combustion chamber is sealed. had one once where fan was blowing pilot out on dhw mode.

carl, February 2008

THERMISTOR`S all working as they should very strange this but since i posted question ive fitted a new heating cut out pipe-stat which was in series with my thermocouple and it seemed ok, but did go out once last night, problem is the ohms drops like mad when the boiler`s cold and fires up just for water, if it drops to much gas value pops out, if it does it again im going to install a 2ohm resister inseries and if pilot did go out for any reason it would still cut the gas valve off and would solve the problem to. what ya think ? ps thanks for your reply.

paul., February 2007

CHECK HEATING THERMISTOR SIMPLE CHECK IS TO DISCONECT HOT WATER THERMISTOR AND PASS CABLES FROM HEATING THERMISTOR ONTO HOT WATER BOILER WILL PROBALLY FIRE UP PROVING THERMISTOR FAULT DID ONE MYSELF LAST WEEK OHMS READING OVER 100 ON HEATING THERMISTOR

STEVE B&H HEATING, February 2007