Gloworm Ultimate

[verwirrt1]

We have a Gloworm Ultimate boiler (reasonably old). It works fine but with one problem. When the central heating is on it fires up and gets all the rads hot then the rads cool and if you turn the thermostat up it clicks as though it is about to fire up...but doesn't. THe only way to get it to fire up is if you run the hot tap for about five minutes...then, hey presto it starts. I replaced the wall thermosat but that has made no difference. I am sure there is someone who might have an idea what the problem is. Had a plumber round who said "could be one of many faults". Didn't want to pay out loads to find fault. Pretty sure it's simple, the clue seems to be in the running of the hot water allowing something to register in the boiler that it can start again. Safety overide???
Any ideas??
thanks

 

[gas_man_gaz]

sounds like ya boiler is only firing up for hw.. iam guessin ch and hw is comin on at the same time until ya cylinder is up to temp then it goes off.. wen ya open ya tap it is coolin the cylinder back down bringin the demand for hw back on...

will need to know wat system its on

easiest way to tell is to look in ya airing cupboard where ya cylinder is and see if its got a stat fitted to the cylinder itself and any motorised valves on the pipework and how many

 

[verwirrt1]

Many thanks for such a quick reply. It is a sealed pressured system. As far as I know there are two motorised valves on the pipework in airing cupboard. There is no thermostat as such on the cylinder, but you can plug it in to get hot water if needed in emergency. Sorry to be vague but am not that technical
thanks again

 

[namsag]

As gaz man says it looks like your cental heating motorised valve is kapout and stuck in the partially open position. May need replacing or just freeing off . Should not be too hard for someone to find this on a visit

 

[verwirrt1]

Brilliant! will get someone to check the valves out....really appreciate the advice!
thanks