Potterton -Performa 24 - Keeps coming on - Micro-Switch Prob

[charlie567]

Hiya All,

First of all, great forum,

I was wondering whether you can help me please, l have a Potterton Combi Boiler - Performa 24

After my gas meter was changed recently, my boiler decides to come on when it pleases (burner on neon light) , this can be every few minutes, then switches off, then the burner light comes on again

It doesn't work with any settings ie from the timer or thermostat

Its in a constant loop of turning on the burner and then switching off again

The Flame Failure light does not appear.

any ideas would be gratefully received on what to do to rectify the problem,

How can l reset the whole boiler, is there a way of doing this?

I have looked in the manual and Baxi website, but no luck

many thanks,
Charlie

 

[Mikeyboy]

Turn off the domestic hot water pre-heat function .

 

[charlie567]

thanks for the reply Mickeyboy

How do l do this - l assume that u mean turn the tap temperature down to zero.

what should l do after performing this,


I have done this and still the burner comes on and turns off

Even if l switch off the timer, to the down position, the burner light still appears, l am unable to control the boiler

thanks,
C

 

[ChrisR]

Are you sure its a "24" and not a "24i" (I'm not sure there was a 24i... where "i" means "instant"ie with preheat)

SOME 24's cam with a preheat they shouldn't have had. I fitted one, so did Tony. Potterton sort of said it couldn't happen! Maybe you have one of those so has it always done it. Suppose you turn the swithc to "off"?

MOre likely perhaps is that water has got to the flow switch so it thinks the tap's on when it isn't, intermittently. Do the rads warm up a bit?

 

[charlie123]

Its Performa 24 on the Manual.

Switched it on and off a number of times.

the radiators do get warm, but my concern is the burner coming on and then turning off every minute, which could cause some damage

 

[just-thinking]

has the pin retracted back into the pressure differental valve ie not in contact with the micro switch assy.
microswitch [3 wire] in front of diverter valve,this can fail and power up the boiler.
a little more info please.
sounds like an easy fix.
see pic on www.partsarena.com/baxi/
muddle through to find your boiler preforma 24.
page 42.part key 103 shows micro switch removed and pin retracted is your pin retracted ?

 

[charlie567]

just-thinking

thanks for the reply,

All that has happened recently is that the gas supply meter was changed.

I have never opened the boiler up until today

The boiler has an internal timer, which can switch the boiler on, off, time to certain hours.

The clock on the timer is working
I switched off the hot water tap temperature and still the burner comes on every other minute. When the burner light is on, l have tried to switch this off from the programme controller (which is within the timer), but it just carries on working

I simply have no control over what the boiler is doing, even if the external thermostat in the stairs is changed to 25 degrees, the boiler is still coming on

The pilot light is coming on and the water is getting hot, so that side of things are working, but in essence, the boiler simply cant be controlled, its in a constant loop of turning on and off, even when u try and switch it off from the programme controller, it still comes on

thanks for the link,

l will check this out soon

thanks again

 

[charlie567]

Page 42, key 103 is the Pressure Differential Assy

cant locate the micro switch assy in the document

 

[charlie567]

Looks like the PCB is knackered

The pin is extracting fine, no problems there, but the front panel of the Boiler is not responding, hence, the PCB is gone....

wat sort of price is a new one please, £65-80?

thanks

 

[just-thinking]

still reckon try the micro switch route first.
but its a boxxocks job to change and not that cheap.
i reccomend you get a potterton engineer to repair your boiler.money well spent.

 

[namsag]

The pin on the hot water diaphragm also sticks causing boiler to fire up . This is in the round 3 inch brass bit facing you bottom left corner . With no HW demand it should retract more or less fully back into housing.

 

[Agile]

It sounds to me as if the DHW flow switch gland is leaking and has caused moisture to get into the microswitch and cause the boiler to think there is a demand for DHW.

It always amazes me how people love to rush out and buy expensive PCBs because they are easy to change and you dont get wet doing so ( until you find it does not fix the problem! )

Tony Glazier

 

[ChrisR]

If you answered the question one asked 8 posts ago - do the rads warm up ....?
If so then look for water in the microswitch on the end of the diverter valve.
If not then look for the pin on the end of the diverter valve being stuck out pressing the switch.
The microswitch is shown in the manual and is easy to access:
It's in the bracket marked "microswitch bracket" on fig 82
here

 

[charlie567]

sori for the late reply, had an engineer round to lok at the boiler

rads warm up and so does the water
microswitch is fine and the pin retracts when the hot water tap is run
there is no moisture round the microswitch

Had a guy come out this morning and he confirms that the pcb is knackered, as the boiler isnt responding to anything at all,

not responding to:

the internal timer
not responding when u turn off the boiler from the switch inside the timer
not responding to the external thermostat, even if the temperature is on 25 degrees

The guy that checked it is Corgi registered, but l am waiting for a price on the pcb, but l will observe him change the pcb and if its not that, l am paying jack for it,

Note, the the boiler only screwed up when the gas meter was changed by Transco

I phoned them up yesterday and told me to basically f off, that they were not liable for any damage caused - cowboys

so, be very weary, if u will have your gas meter changed in the future by Transco

thanks for all your help guys,

it has helped me underatand more about boilers.

thanks again,

 

[Agile]

All those symptoms are those of the DHW microswitch being "on". You blandly say "its fine".

Can you explain what tests you have performed to determine that "its fine".

There is no way that I can envisage whereby merely changing a gas meter can do any permanent damage to a boiler!

Tony Glazier