boiler died after bleeding radiators...

[teeIY]

Hi, I could really do with some help!

I have a Gem combi boiler, which I'm guessing is about 12 years old or so. I don't know anything about the history of the boiler, because I just moved into the flat. I'm aware that Gem boilers aren't very commonplace.

The boiler was playing up a bit from when we first moved in, e.g. the overheat reset light coming on fairly often. The timer wasn't working properly - clock was ticking round, but the segments weren't clicking to turn the boiler on. Also, sometimes the hot water wasn't very hot - hot enough, but not very hot.

Anyway, today I decided to bleed the radiators. I then topped up the water pressure to just above 1 bar. When i turned the boiler back on, the overheat reset button kept coming on, with quite a lot of noise. I managed to get it to fire up for a while, but it went off again after a few seconds, with a very slight smell - possibly electrical. Now it's completely dead - it does absolutely nothing when I turn on the heating or the water. I checked the fuse in the plug, which is fine. In fact, I can still hear the clock ticking round.

Has anyone got any idea what could be wrong? The pump? Some of the electrics? I'd like to get a rough idea of possibilities, so I can figure out whether it will be cheaper to get a local plumber round (I've found one on gumtree at £35/hr) & pay for parts, or to go for the £156 flat fee from British Gas. The cheapest place for Gem parts that I've found is here... http://www.europeanspares.com/index.cgi?command=list&pos=24&visit=1196963986-12222 The timer alone is £63, which is more expensive than other brands of boilers.

Eagerly awaiting your advice...

 

[ChrisR]

Overheated due to trapped air and popped out a reset button - which you'll have to hunt for, sorry!
Meanwhile find the automatic air vent (look up AAV) and make sure its cap is loose.

 

[gasmick2]

most overheat stats should be in a place where you can see it try looking on the top of the boiler to see if there is a small red button or it could be on the top of the front panel it does sound like its got air in the system and the auto vent is clogged up the other thing of course is the pump

 

[teeIY]

thanks for your tips.

i forgot to say that i've already reset the switch, but nothing's happening. could the overheat thermostat be broken now?

i'm just about to take the cover off to check the automatic air vent. i'll let you know what i find.

if it is the pump, will i be able to tell from looking at it?

 

[teeIY]

ok, i couldn't actually find anything just from taking the cover off, but what i have noticed is that there is a small amount of water dripping from inside. any idea where this might have escaped from?

 

[undercover]

Water could be from the AAV when the boiler overheated due to the airlock.

Have you tried to reset the O/H stat button yet. Occasionally they can take a while to reset.

 

[gigz]

Could be from vent on top of pump, its usually a little black thing about the size of a drawing pin. Open it to release all air, if it wont stop leaking once fully bled close it. Try googling pump to see what your looking for.

 

[teeIY]

the reset switch stays pressed in, as if it's ok. that's why i thought the problem might be coming from the overheat thermostat itself, rather than the switch, or even somewhere else in the circuit. that might have explained the funny electrical smell.

 

[bengasman]

The overheat stat come on for a reason; safety. If you have reset it dozens of times, chances are something died. Even if you can fix that, you would still have the original problem. I would strongly recommend getting a pro to look at this. Imagine what can happen if the safety fails to engage due to a bad repair