Britony 80

[Frikkin Freezzin]

I have got the ever reliable britony 80 boiler.
the boiler keeps lighting up and then the flame stops when the switch is either in hot water mode or C/H mode, but 2 out of 3 rads in top of house get warm, hot water works ok. when H/W tap is turned on and off quickly the system switches into C/H and all rads get hot. this then works fine until timer turns heating off, after a while boiler starts igniting again and carries on as before. so far, 3 way valve and thermistors have been replaced. apart from hitting boiler with a big hammer, any ideas what to do next?
thanks for any possible ideas or suggestions.

 

[gas4you]

Don't really know these combi's but could it be the water throttle sticking, or the head faulty?

 

[gas_man_gaz]

the dhw flow switch is common fault. it sticks on causing the boiler to fire for hw but with the tap not runnin the boiler heats up quick and cycles on and off (due to the diverter valve sending the water around the hw circuit). sometimes cause's the boiler to overheat aswell.
just a thought?

 

[Frikkin Freezzin]

i took this off before, is does not seem to stick,(but will be replaced) but could you tell me if this is supposed to be one unit, as the head is not connected to the metal plunger unlike the one on the cold water flow which has a gator holding it all together, also the thermistor on the left hand hydraulic block was black when replaced, does that indicate anything?
would this also make it start working eventhough the the timer is off?
thanks

 

[gas_man_gaz]

for some reason jus about every brittony, well what i've worked on seems to acumalate the black muck and it does affect the thermisters but wouldn't cause the boiler to fire without demand. as far as iam aware the pump provin switch and the dhw flow switch are the same and do come in two pieces.

easy way to test weather the dhw flow switch is at fault is to disconnect it and put the boiler on heating and water and put a demand on the heating. does the boiler fire and start warming the rads? before the heating is up to temp reconnect the dhw flow switch, does it now cycle on and off as before?

 

[Frikkin Freezzin]

thanks gas_man_gaz.
turned off boiler for 10 mins, unplugged dhw, turned back on to heating and water, no response from boiler, plugged back in boiler starts as before, on and off. does this help?
cheers..

 

[Gasguru]

Change the DHW flow sensor assembly.

If you have a multimeter you will find the contacts are short circuit.

The small tines in the reed switch often fail shorting together.

Later assembly has been modified.

 

[Agile]

The small tines in the reed switch often fail shorting together.

Whats a "tine" ?

The flow and DHW switch collect dirt because they are operated by a magnetic shuttle which attracts magnetite.

You can hear them operate and test the continuity.

Sometimes water leaks into the reed and will bring on the DHW even with 200,000 ohms resistance.

I was once fooled because I tested the switch on continuity but not on a high resistance range as well !!!

Tony

 

[Gasguru]

"tines" are the prongs on a tuning/garden/eating fork

or the teeth on the bucket of a JCB

or the spikes to aerate the lawn

or the small contact strips in the reed switch.

Either the tips arc together (I think unlikely in the Brittony) or more likely the tips become magnetised over time due to poor quality tine material.

One day they will advance to Hallogic sensors.

 

[Agile]

I dont think the Britony will ever advance.

But the Biasi already uses a Hall effect detector on the DHW flow detector ( and some on the system flow switch too ).

Tony

 

[Frikkin Freezzin]

changed the DHW flow assembly, no change made, still keeps firing up and going off after a few seconds.
any more ideas? i still recon a big hammer may help!

 

[Gasguru]

Did you not test the DHW flowswitch with a meter to confirm it was faulty?

You have definately changed the DHW flowswitch and not the primary flow switch assembly sitting next to it.

 

[ollski]

I have got the ever reliable britony 80 boiler.

Ah you got it did you?, so that's why I've ended up with all the awful ones then.

 

[Frikkin Freezzin]

cheers gas guru. did put it in the wrong one, i miss read the diagram. heating working fine now..thanks to you and gas man gaz.

 

[gas_man_gaz]

glad to hear ya sorted! the guru int bad is he, jus dnt mention bg