Potterton Puma 80

[nap]

My circuit board has caught fire! How easy is to replace? and what could be the cause?

 

[corgiman]

they are really easy to change, just make sure you get the right board for your boiler, its it pilot or not?

as for why raden could probably tell you?

 

[Agile]

I would say they are fairly easy to replace but the CH output has to be set correctly.

When we change them we do a basic service and check the boiler for correct functioning.

Tony

 

[Rob]

They always set fire! top left hand corner.

plug p1 is the main 240v supply to the board, do you keep switching off the boiler at the spur?

 

[gazthepottertonengineer]

check it hasnt melted the platic connector as well

 

[geoff@cetltd]

Yeah - I have a supply of 8 way molex connectors - I gave a customer one (plus the connector pins) today in fact

If you have the two pcbs side by side, simple to change

You have to know whether you have a perm pilot or an electronic Puma

The Perm pilot has a link (LK1) which routes a tapping on the primary side of the mains transformer to the fan to run at slow speed to remove the products of combustion of the pilot light when the boiler is not firing

 

[ChrisR]

The E board has a stack more components on it too. Have yet to come across anyone who knows what they do!

 

[Agile]

I wonder what Geoff will say?

 

[geoff@cetltd]

In the beginnnig was the board, the one board, the only board

The difference between the perm pilot and the electronic version was just the link LK1 which routed a tapping off the primary side of the transformer via RL2 to give a slow speed fan for the PP version, the link being cut on the electronic

Then came the slightly more robust version where one corner of the board is more populated on the electronic version and has an extra capacitor on the PP version

The honest answer is that I don't know exactly because a) it's not an area of the board which is prone to faults and b) by the time we started seeing any quantity of the later version coming through, I was paying other people to repair the boards and I relegated myself to office monkey


So there you have it

 

[Agile]

There Chris, you are an egit and he is a monkey!

He went to M&S instead of Colindale!

Why dont you assess the extra circuitry Chris?

Perhaps they are irrelevent components added for fun???

For example the Lynx air flow element resistance is about 1.4 ohms but they add in parallel a resistance of about 1400 ohms wilci will make negligible difference. The basic element was used in a cooker igniter many years ago!!!

Tony

 

[geoff@cetltd]

There Chris, you are an egit and he is a monkey!

He went to M&S instead of Colindale!

Tony

Don't look at me - I had no say in the matter

 

[gazthepottertonengineer]

In the beginnnig was the board, the one board, the only board

The difference between the perm pilot and the electronic version was just the link LK1 which routed a tapping off the primary side of the transformer via RL2 to give a slow speed fan for the PP version, the link being cut on the electronic

Then came the slightly more robust version where one corner of the board is more populated on the electronic version and has an extra capacitor on the PP version

The honest answer is that I don't know exactly because a) it's not an area of the board which is prone to faults and b) by the time we started seeing any quantity of the later version coming through, I was paying other people to repair the boards and I relegated myself to office monkey


So there you have it

the simple answer is that the boards are designed and mass produced with alot of extra resistors and cicuitry which is never used but it is apparently cheaper to leave them on than redisign the pcb without them ! i dont understand the logic behind that one myself but its the same with alot of pcbs

i personally just carry pilot pcbs and cut link 1 if i have to fit it to an electronic version as Raden is right is the only differance

God cant believe im agreeing with him on something thats a first

 

[geoff@cetltd]

the simple answer is that the boards are designed and mass produced with alot of extra resistors and cicuitry which is never used but it is apparently cheaper to leave them on than redisign the pcb without them ! i dont understand the logic behind that one myself but its the same with alot of pcbs

i personally just carry pilot pcbs and cut link 1 if i have to fit it to an electronic version as Raden is right is the only differance

God cant believe im agreeing with him on something thats a first

Well ...

Actually that's not correct with the current versions

There is circuitry in one corner on the electronic version which is missing on the PP version - which instead has a (220u (?)) capacitor

 

[Softus]

For example the Lynx air flow element resistance is about 1.4 ohms

Lynx ® ?

 

[gazthepottertonengineer]

the simple answer is that the boards are designed and mass produced with alot of extra resistors and cicuitry which is never used but it is apparently cheaper to leave them on than redisign the pcb without them ! i dont understand the logic behind that one myself but its the same with alot of pcbs

i personally just carry pilot pcbs and cut link 1 if i have to fit it to an electronic version as Raden is right is the only differance

God cant believe im agreeing with him on something thats a first

Well ...

Actually that's not correct with the current versions

There is circuitry in one corner on the electronic version which is missing on the PP version - which instead has a (220u (?)) capacitor

Agreed but wot extra does it need to do ? apart from run the fan at low speed