help please. baxi combi 80 eco.

[DontAsk]

well this is my gem of a boiler,it has worked very well for 18 months.
now i am getting very poor temperature in the hot water,heating is ok.
pcb has been changed 18 months ago due to a total breakdown,also serviced by same guy.
burner pressure on water only starts at 12 mbar after 45 seconds drops to 4mbar.
burner pressure on radiators starts at 12 mbar and maintains at 12 mbar for 24 mins then goes down to 5 mbar.
back to water production,removed ntc/sensor from flow pipe and 12 mbar is maintained but still same warm water,no difference.
flow rate is 9 liters a minute also turned off heating flow isolation valve.
so any ideas.
thanks in advance.

 

[gas4you]

Check that the ch flow is not getting hot when hot taps are run. Could be DV.

Could be plate HE blocked on system side if not.

 

[Agile]

I would be very surprised if it really runs for 24 minutes on full power of 24 kW.

Thats a lot of heat unless you live in a ( big ) castle.

I have to say "big" because we have a customer who does live in "The Castle" but its only a small flat in Riffle Road.

Tony

 

[DontAsk]

gas4you and agile,thanks for prompt replys.
gas4you,i have turned off the heating flow isolation valve to double check no heat is escapeing to radiators.so you think the flat heat exchanger is restricted.
agile,the property is a draughty old london house,original windows,high ceilings,open plan throughout ground floor, 4 12 foot x 2 foot doubles on ground floor and 11 more radiators.
so could it be a restriction on water circuit.diverter valve front pin goes in and out instantly and quick.
thanks.

 

[Agile]

4 12 foot

thanks.

12 foot long rads?

Wow, those are some rads ! I am not even sure that I have ever seen any.

Well perhaps it might run the heating on full power for 24 minutes then.

Dont you think that you should be doing something about insulation and maybe getting a condensing boiler?

Tony

 

[DontAsk]

thanks for reply tony.
your comments about insulation,yes insulation could be improved.
about fitting a condensing boiler well i would consider that if only i could get one that will last for 6 years without breaking down.
see many condensing boilers here have a poor record and many exchanged after only a short time,isar/icos.barcelona for a start.
anyway plenty of merchants still selling non condensing boilers here in london.
anyway going to the expense of a new boiler and what goes with it is rather expensive,or exchange my hot water plate heat exchanger or divertor valve is reasonably cheap.
tony are you in training to work for BGas,sell.sell.sell unnecessary upgrades.
ps,thank you for not mentioning it needs a powerflush.
so you failed BGas interview.
thanks.

 

[gas4you]

If you have turned off the ch flow isolator, how can you tell if the pipe is getting hot on HW only

 

[baxpoti]

If you have turned off the ch flow isolator, how can you tell if the pipe is getting hot on HW only

Very true, but by isolating the flow all water is pushed through the plate heat. If problem persists, diverter is eliminated.

Classic case of plate heat blocked


...... famous last words

 

[namsag]

You could take out and soak the plate in x800/ferroquest overnight if not a new plate is only £40 inc and takes 10 mins to remove and fit.


Your pressures 12mb presure is ok but when it drops down it should drop all the way to 2.5mb this is also its ignition pressure. Not the cause of your problem but needs tweeking

 

[Agile]

I have no connection with British Gas.

It seems that your plate HE is blocked as already advised.

There have been some unreliable boilers and they are now condensing models.

Its normally illegal to fit non condensing boilers in domestic property.

There are some very reliable condensing boilers like the Ecotec and Biasi M96.

You seem to have a not very reliable boiler and choose not to engage professionally qualified people to repair it.

Tony

 

[DontAsk]

thank you to, gas4you,baxipoti and namsag.i fitted a new plate heat exchanger and now hot water back to a constant reliable temperature.
the need to exchange my boiler for a cond(break down more often)ser.
from a top poster was not required,seems like someone is short of work and hunting here for work.
after being mucked about by a large parts supplier who said they had 3 in their stock,supplier has pc in their name and parent company has a w in it,well they wanted to sell me a cleaner for £38.00 plus vat.
anyway got the part for £20 .00 and a free tube of grease silcone.from aboves car park.
its a one off sale but i am happy.
thanks all.

 

[petit_pablo]

ps,thank you for not mentioning it needs a powerflush.

Ironically a flush wouldnt go amiss here or at the very least a filter of some description on the return before the boiler. The plate heat exchanger is blocking because of system debris.

 

[DontAsk]

thanks for reply,power flush=£400.00.or new plate h/exch £40.00.
but still thank you.

 

[petit_pablo]

Untill the next time it blocks, and it will.

 

[DontAsk]

thanks petit pablo.
i have the blocked plate exchanger in front of me now and it is now dry,i can see flaky black slivers if i shake it about.
the plates inside are very close together,so i can clean it out,but why should i bother as a new one in 3 years time will still be reasonably priced,these units fit a few boilers.
thanks anyway, my gem of a boiler is working great now.