Potterton Puma 80e Low pressure switch + release valve

[JBseymour]

Hello there, I wonder if any one could help me?
I want to replace the pressure relief valve as over time it keeps releasing the pressure and I periodically need to re pressurise.
It looks like there are two 3mm grub screws top and bottom that hold it in place?
These are solid and I've tried getting the blowtorch on them but no luck yet. I don't want to strip the hex head bit.

The other small prob is the low pressure switch. I thought this was just an on/off switch or does the PCB look for ohms? When the pressure is low, measuring across the 2 terminals there is a circuit as you'd expect and when the system is filled the circuit is broken.
However when I plug in the 2 yellow wires the LED is back on??
I'm guessing a need a new switch but I'm scratching my head about this, because it seems to be working as it should.

Any illumination appreciated

 

[Mr Smyth]

No need to change the whole thing.
Once the pressure is zero and the boiler is drained get a pair of grips on the black plastic edge of the PRV and unscrew it from the brass fitting. The workings of the PRV can then be cleaned/changed. Make sure you clean/check the inner edge of the brass part for scale/muck. Whilst the prv is open/out check the pressure of the expansion vessel (see FAQs)

Hope this helps

I rarely change the whole thing, 9/10 times it is far easier to just change the workings. The PRV letting by is nearly always related to another fault. Often the exp vessel or the pipe leading to it.

As for the LPS probably needs a clean, wind it out and check that the hole back into the diverter valve is not blocked

 

[Agile]

The LP switch operates on that boiler contrary to what you might expect.

Its open circuit when there is pressure in the system. However you must measure on a high resistance range.

There are actually three connections but one is blanked off on installation.

Check yours is correctly connected and is high resistance when the pressure is up.

Tony

 

[powell30]

And if you want you can remove one of the LP connections, this will remove the lp light and allow the boiler to work. All you need to do is check occasionally if the boiler is still at correct pressure (once a week?)

 

[Deleted member 105431]

And if you want you can remove one of the LP connections, this will remove the lp light and allow the boiler to work. All you need to do is check occasionally if the boiler is still at correct pressure (once a week?)

That is Riddor reportable (illegal). If the boiler dry fires it can do pernament (and expensive) damage and is dangerous.

 

[twgas]

And if you want you can remove one of the LP connections, this will remove the lp light and allow the boiler to work. All you need to do is check occasionally if the boiler is still at correct pressure (once a week?)

That is Riddor reportable (illegal). If the boiler dry fires it can do pernament (and expensive) damage and is dangerous......

.....I agree, testing is one thing, using it like that is a tad silly!!!!!

 

[JBseymour]

The LP switch operates on that boiler contrary to what you might expect..... and is high resistance when the pressure is up.-Tony

Ah thanks Tony, that explains it. I reckon it might be toast as I've cleaned it etc.

I'll check the pressure expansion vessel later today. So if I've understood it's purpose correctly, the air pressure is low or non-existent, then the water will expand when hot, have no where to collect and force out of the PR valve?

 

[Agile]

That is Riddor reportable (illegal). If the boiler dry fires it can do pernament (and expensive) damage and is dangerous.

Thats true, but you cannot Riddor Potty when they did not put the LP switches on some models of the Puma!

Tony

 

[Deleted member 105431]

That is Riddor reportable (illegal). If the boiler dry fires it can do pernament (and expensive) damage and is dangerous.

Thats true, but you cannot Riddor Potty when they did not put the LP switches on some models of the Puma!

Tony

modifying/bypassing a safety mechanism is one thing. pi55 poor design is another.

 

[JBseymour]

As a bit of feeback, I tested the expansion vessel which had virtually no charge. Is there a boiler that features intelligent design where the valve is actually easy to view and accessible? After trying to connect a couple of bicycle pumps with no luck because of the stupid location, I used a 12v tyre pump from my wife's car to bring it up to 1 bar.

After charging this and eventually getting air out of the system I have had no problems since with low system pressure. The low pressure switch didn't look clogged up but I disconnected it, put a 2/3mm hex key inside and operated the plunger. With the wires plugged in it was easy to see the LED switching on and off. I think it was just a bit sticky after lying dormant for so long.
Thanks for your help

 

[JBseymour]

Whoops double post and no delete option

 

[Agile]

Is there a boiler that features intelligent design where the valve is actually easy to view and accessible?

After trying to connect a couple of bicycle pumps with no luck because of the stupid location, I used a 12v tyre pump from my wife's car to bring it up to 1 bar.

Boiler makers dont seem to always have the gas engineers convenience in mind.

The early Biasi has it conveniently at the bottom but later models its at the top.

I still have not found out where it is on the Ideal Sprint!

You only need to connect ONE foot pump! I have never had any problem connecting one though.

Glad you got it sorted with our help!

Tony

 

[JBseymour]

I meant I tried to connect a couple designs of pump. I tried the conventional type with the small hose attachment and the new type where the pump clamps right on to the valve. It was tricky getting it to screw on due to the angle and not being able to see what i'm doing -there was no room to pump the damn thing when I finally did.

Now I have visions of some heath robinson contraption with two pumps connected in series

 

[Agile]

There was a Halfords long tube extension a few years ago but no longer stocked.

I supose I could make up one.

Tony