low pressure on combi

[VeRetired]

Hello
I have a potterton puma 80e, its about 9yrs old and it is giving me problems. The Led (LSP) on the front panel, 3rd light up, was shows red and I cannot not get any hot water or heat.
I have read past messages of other Pott owners and i think i've got a fault the same as others who have a puma 80e. Its saying low pressure but the pressure gauge is at a steady 1Bar and there's no leaks. I've carried out a couple of simple things to see if i can put it right.
1. cleaned out crud from the pressure switch and valve port. Forced water under slight pressure, by mouth through a tube, through the pump drain-off and water spouted out the pressure switch port, also reversed that action = No blockage
2. tested pressure switch's continuity = OK
3. scanned the back of the Mod PCB through a powerful magnifying glass
= No dry joints
What do you make of this, i disconnected one of the yellow wires from the W.P.Switch and the boiler came on, heat and hot water on demand if i pushed the on button, i didn't let it run too long. But the sheer pleasure of a heated room. I'm tempted!!!
What is the problem?
I'm making this appeal because i can't afford to go to a big name repairer and i don't employ cowboys. The heating engineer who fitted the system has not returned my two messages left on his machine. So help if you can
Thanx in advance

 

[kevplumb]

2. tested pressure switch's continuity = OK


under pressure or not

the switch should go open curcit when under press

thats why it will run when you remove a wire

 

[VeRetired]

I'd appreciate it if you could just make your comment a little clearer. This is a help forum. is'nit????

 

[kevplumb]

did you test the switch for continuity under pressure or not

yes its a help forum but nobody has to answer either

 

[VeRetired]

The switch was tested under pressure. BTW. I DO appreciate the help and I know too well that you don't have to answer. Like many who've been left forsaken before me.
I do a help thing with a computer help forum and if I'm caught short on an answer I scour books or do a phone about, but I DO help and I certainly do not substitute a smarty pants retort for a constructive answer if I can't deliver. So if you can't help with the problem or spell then don't.

 

[kevplumb]

the switch goes open under pressure and closed when not under presssure did you test it under pressure or not

simple question

BTW my spelling might not be to hot but read some of the old posts most people seem to understand me ok

 

[Igorian]

Errm, I think he has helped. You have continuity under pressure where, according to Kev, you should have none. Well, that's how I read it.

 

[kevplumb]

cheers ig

 

[Igorian]

I can see the problem. It's the nut that sits just in front of the wheel

 

[VeRetired]

Thanks Kev. Sorry about rubbing you up the wrong way, but it did spark you into giving me an answer and I'm very grateful.
So tell me, why does the system die when the switch is wired but come to life when I pull a connector off one of the terminals. The switch is about 3mths old, he system is pressurized and its 1 below outside.

 

[kevplumb]

switch is stuck or shorted

as in you pull the wire off it goes open and fires

 

[VeRetired]

Thanks for your help.
I can't get a heating eng. just yet and we are heading for a very cold spell. Am I putting life in danger by running it for short periods, 'til a heating engineer gets to me.

 

[kevplumb]

should be ok if the pressure is ok

 

[VeRetired]

Thanks for your help.
May the sun always shine on your face, (and into our living room)

 

[PEDANTICVINDICTIVEMAN]

I thought it shone out of Kevs arsse