Bosch combi boiler playing up

[AceOfHearts]

Over the last couple of weeks my combi boiler has been playing up, and has gradually got worse to the point that my shower this morning was cold

The symptoms are that the hot water is only coming out luke warm, and if i restrict the taps to only a trickle it only ups the temperature a little. The boiler looks to be running fine (kicks in and the flame looks strong) it just can't heat up the water.

After some reading online I will go home tonight and run the hot tap for 5 minutes and see if the flow and return are heating up on the central heating, I will also check the function of the heating system as i am not sure if it is working or not.

Does anybody have any advice or tips on what to look at? In my mind it could either be the diverter sending the hot water around the CH system (which i will check) or maybe a build up of sludge in the heat exchanger?

How can I flush the system through, is this something I can do myself? I would rather not pay someone to come out (I am skint and a service engineer by trade so am capable of doing the non-gas bits myself but have no experience of domestic systems as this is my first house)

All help appreciated

[AceOfHearts]

Thanks for the replies so far

I will get the exact model when I get home and post it up (at work at the moment)

[AceOfHearts]

Hi everyone,

I have just tried running the kitchen tap on hot at only a trickle, and it does eventually get hot. I ran it for around 5 minutes and the central heating flow was just as hot as the domestic hot water and the upstairs radiators were beginning to get warm!

The boiler is a Worcester Bosch 240 Combi RSF

[AceOfHearts]

Thanks guys i will get one on order when i get back from Le Mans and let you know how i get on

[AceOfHearts]

After 20 minutes looking online and finding the part number in my servicing instruction booklet this is the cheapest I have found

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&am...

[AceOfHearts]

VERN UK said:

Bang on pal, that will sort it, manual will also give you the steps to fit it etc

The manual says basically remove and replace so should be quite self explanatory

I will get all new valves as well, nothing worse than trying to do a job when all the valves are letting by

[AceOfHearts]

Thought I would update this thread, basically the boiler seemed to sort itself and hands been running OK for almost a year, but last week went back to the same old tricks.

I have just (today) replaced the diverter valve and have repressurised the central heating. Everything kicks on when the hot water is turned on and there is still no hot water!

I am thinking now that it might be the water-water heat exchanger as I can feel it getting hot, and can feel the cold mains coming in but no hot coming out. Very frustrating

[AceOfHearts]

Oh ffs now the neighbour is complaining about the noise

Looks like we have no hot water now

[AceOfHearts]

Another heated debate with the next door neighbour at 8:45 last night

The heat exchanger is now out and i am curently soaking it at work in cherry acid.

A lot of crap seems to be coming out already and even when empty it weighed a ton so hopefully this should sort the problem.

[AceOfHearts]

Got it back in last night, but run out of fibre washers for the last two connections

I am popping out today to get some more, but will not be able to finish the job off until tomorrow morning (at work)

Once this is done the boiler will have had a de-scaled heat exchanger, new diverter valve and new gas valve this year. Hopefully it will stop playing up for a few years after this

I will get some photos too if that is of any help?

Edited by AceOfHearts on Sunday 2nd June 09:38

[AceOfHearts]

It is fixed!

Water gets hot and stays hot. Very happy and no leaks

The calorifier was actually quite easy to get out as well (about an hours job) so i may start doing it every couple of years to keep it clean.