potterton puma 80 (flame cuts out when cold water turned on)

[joserulz73]

Hello
I have a potterton puma 80.
when i turn the hot water in the basin on the boiler fires up and keeps running, but as soon as i turn the cold water on in the basin or bath the boiler cuts out.
has anyone had a problem like this?
Jose

 

[Rob]

Possibly the flow switch on its way out. The boiler needs atlease 3 litrs a min thorough the hot tap to work so make sure its above this with both taps on.

 

[joserulz73]

hi rob

i have changed the flow switch and checked the flow rate its at 6 litre per minute.
any other ideas m8?
cheers

 

[Baxmax]

Is the flow rate 6L per minute whilst running both hot and cold taps.

 

[joserulz73]

hey baxman
roughly 6 litres hot only
the cold water is a bit more .
cheers

 

[gas4you]

Could be your problem then, when cold is run at same time hot flow will be dropping too low to operate flow switch

 

[joserulz73]

hey dave
thanks for your reply
i held the microswitch in and the boiler still cuts out when cold water is turned on elsewhere.

any other ideas?
cheers m8

 

[gas4you]

Is it cutting out because it is going to overheat due to poor flow through it when other cold taps are turned on?

 

[joserulz73]

dave
it cuts out as soon as i turn cold water on
the boiler doesnt over heat.
ta

 

[gas4you]

How about the water pressure switch? Could be knackered or doing its job by cutting the boiler out when cold inlet pressure drops as other cold tap switched on!

 

[joserulz73]

dave

how would i check if its working?
i disconected it and the boiler fired up but cut out again when i turned the cold water on.
please let me know how to check if its faulty.
thanks

 

[gas4you]

The only real way is to replace it, but I still think it is ok and just doing its job by shutting the boiler off when pressure drops.

 

[gas4you]

Come to think of it, this prwater pressure switch is probably the system presure safety switch and nothing to do with inlet pressure

 

[joserulz73]

morning dave
just as well you said that, i was going to try and get one today.

so i will leave that out.

i dont know if this is anything to do with it, but the the pcb blew up in the top left so i got one for the same model boiler but i noticed that a few parts on the pcb where different, do you think that maybe the cirquit board could be the problem?
cheers
[/list]

 

[ChrisR]

1)
If you've pressed in the flow switch manually (the one coming from the 4? inch diameter part on the left) then the boiler doesn't know anything about cold water . It would come on even if there were no water in any of the taps in the house.

It would overheat pretty quick, but that isn't the problem.

So you must be lying to us, OK?

2) Forget the pressure switch - the boiler works with that disconnected.

3)Have you got a permanent pilot or not. There are two "boards" and you need the right one. Same boards - different bits on it.
If you have pilot you MUST have LK1 in place. It's a wire link about 2cm long just below the fuse holder. If it (and C17 1cm diameter in middle of board) isn't there, then you have the board for the electronic ignition version.
If they are there, but there are lots of bits missing from the lower left of the board, that's the pilot version.

Actually the part number should be on a wee label, like 21-18801.