britony 80

[casper1973]

i have a britiony 80 combi that has suddenly stopped working on heating hot water is fine so i changed the flow valves then followed the service fault diagram that says change the diverter valve or 3 way valve no joy. the pipe up to the ch isolator tap on left is hot up to the tap pump is running unable to get flow can anybody help

 

[ollski]

Have you bled the air out of it and is the pump physically running or just humming?

 

[casper1973]

it has self bleed but i feel the boiler is air free and after doing all what i've said thought about a pump prob so i removed it to check whether the impellor had broke of it no joy

 

[ollski]

it has self bleed but i feel the boiler is air free and after doing all what i've said thought about a pump prob so i removed it to check whether the impellor had broke of it no joy

Yes it has an automatic air vent, but does it work?. The pump is more likely to stick than actually be physically broken.....can you see it spinning when you take the screw out of the end?

 

[casper1973]

the air bleeder foams after the system has been open and yes if u remove the screw the pump is moving ok

 

[ollski]

Well you could swap over your ch and hw thermistor just to see if that cures it without spending any more cash, but I reckon the smart money now would be on your ch flow switch.

 

[casper1973]

the flow switches have been replaced but you mite have something with the thermistors if the thermistor is faulty could it shut the 3 way valve if so this may well be the fault

 

[Slugbabydotcom]

the pipe up to the ch isolator tap on left is hot up to the tap

I know it may seem a silly question but is this and the other ch isolator open?

By closing these valves one at a time and opening the PRV you can flush the system both ways by opening the filling loop valve to clear most blockages except those caused by lime. At least if you do this you can check out the flow and begin to home in on a circulation problem if one exists as you suspect.
After treble checking everything you have done so far and before you move on to the next item in your fault finder, from experience consider replacing the boiler now before it empties your wallet of more good money that could go towards a new one.

 

[Slugbabydotcom]

the flow switches have been replaced but you mite have something with the thermistors if the thermistor is faulty could it shut the 3 way valve if so this may well be the fault

Thats what I thought at first but ch thermistor is used on hot water draw off so this is unlikely.
On these you can swap ch and hw thermistor leads over to check them
[Voilet and green leads]

 

[Agile]

Unfortunately you use very few words to say what you have done.

It appears to me that as the fault chart indicates at first sight the diverter valve needs to be properly checked. Firstly that the motor head is driving correctly and secondly that the diverting paddle is actually moving.

The flow switches are a problem as they pick up magnetic cludge. I did once come across a difficult fault with your symptoms and it turned out to be the DHW flow switch which was slightly wet and the off resistance was 40 K ohms but this was enough to hold the boiler in the DHW mode.

Two checks you can make are to say if the diverter valve motors when DHW usage ceases with a CH demand. If not then does it motor when the DHW flow sensor is disconnected.

Fault diagnosis has to be logical and based on an understanding of how the boiler operates!

Tony Glazier

 

[corgigazza]

This boiler has filter fitted on the return r/h isolator elbow feeding the pump. check m/i booklet

 

[Agile]

Thats a good point although not terribly clearly expressed for a DIYER.

Within the right hand CH isolator valve under the boiler there is a gauze filter which is the simplest reason why it might not be working on heating.

I dont remember if its between the valve and boiler which would be most convenient or between the valve and the heating system which is much less convenient. Probably the latter! If the diverter is moving then next take this valve apart and check the filter which is probably clogged with dirt.

The idea was that this filter would remove the magnetic debris which would clog up the magnetic flow switches. I can only say its not completely effective. ( The surprisingly similar Baxi Bahama has all the same problems! )

Tony Glazier

 

[gaza]

casper
check the isolator valves are open. this may sound obvious but i have had the same problem when asked if i could look at a britony 80 today.which has not been used for 18 months,had to change pump, gas valve stuck , diverter valve goosed.fitted new turned on boiler would not heat rads fully.took off the black plastic knobs to find flow isolator only part open although with knob on it looked open.turned it open works fine now.

 

[bradleybear]

Know it sounds daft but have you got TRV's?
Are any open?
I.e. path of water to flow to?
This time of year with milder weather and no external bypass can mislead you into not checking the basics

Also, from cold start, does the boiler fire for heating, turn ch on, does boiler fire, and then go off after short while? Could be diverter valve if so, although you have already changed. Check motor on diverter valve is operating ok, with head removed and turn ch on, and alternate turning hw tap on to see if it is moving.

PS Did you know you can get a service kit for these divrter valves at about £50 cheaper than the complete valve, same diverter valve as Ideal Isar.

 

[gaza]

how do you check if motor is working as you have to drain down boiler to remove valve.just replaced a new valve at a cost of £54.+vat