Another Potterton Puma 80e problem (sorry)

[Morphim]

All was pretty much working fine yesteray. Today, the central heating keeps locking out. Hot water seems fine.
However, I've noticed recently (last couple of weeks) that the water pressure seems to keep being low (as displayed by the pressure gauge). I obviously fill this up. The pressure needle rises much faster than usual (as if it's filling a much smaller area)
There are no apparent leaks and all the rads are full.

So, when the Central heating is turned on, it runs for around 1min, then the pressure gauge shoots right round to max, lots of banging, boiling and noise, the lock out light comes on and the pressure drops back down.
It's also venting small amounts of hot water over my garage floor everytime it does this.

Any ideas? Any help gratefully received.

ps. To top things off, the light in my garage (so i can see what I'm doing) has just blown too!! Brilliant, eh

 

[Rob]

Pump has failed

 

[ChrisR]

And see FAQ - Pressure Problems

 

[bengasman]

Pump or diverter dead or seriously dirty system, not a diy job

 

[Razor900]

And the winner is ChrisR, the expansion vessel has either split internally or simply lost its charge, diy if you can be trusted with a footpump!!

 

[Morphim]

thanks for the replies

Pump is fine, which is a shame because I had 4 grand waiting to pay you to replace it

System is clean as a whistle, diverter seems OK too.
BTW Any job is a DIY job

ChrisR- I concure. After reading the FAQ, you seem to be right on the money. Thanks for bringing my attention to it.

Razor900 - I can't be trusted with anything!!
I'm off to find my party balloon pump now

Cheers for your time, guys. I'll let you know how i get on

 

[Lee4all]

Pump is fine, which is a shame because I had 4 grand waiting to pay you to replace it


The advice given here is good, free and so i think your reply is O T T.

 

[Morphim]

I'm sorry but I disagree.
I think most of the advice is great, whether free or not
However some is really bad; and a lot of it comes from so called 'professionals'; the same people who are quite happy to rip people like me off due to our lack of knowledge rather than ability.

There are few domestic jobs that aren't DIY jobs. Most that aren't are purely due to having the right tools and, as i said, the knowledge. That's what makes the internet so great. When someone asks how to do a certain job and a 'professional' appears and says 'don't bother, buy a new one / get a plumber / electrician / builder in.' I'm sure the reason the person asked is because they already considered this and decided to chance their arm on a forum instead. If it's clearly explained why it might not be worth doing, fine. But at least give an explanation. If not, it's no help at all.

Anyway, the reason i have returned is to say that the pressure in the expansion vessel was the problem.

The expansion vessel valve can be accessed at the top, back, right of the boiler. The vessel itself is a flat, round, red thing which sits vertically at the rear of the boiler (right near the top, against the wall)

It holds air, to a certain pressure (in this case 1.4bar) which is allowed to compress to allow for expansion in the rad system water as it heats up. If the expansion vessel pressure is too low, the hot water can't expand and it gets too hot which causes the boiler to cut itself out.

This is what i did>>

Turned off / unplugged the power to the boiler.

I released the rad system pressure by firstly opening a bleed valve on one of my radiators in the house. Then, after the pressure had dropped enough, I unscrewing the whole bleed valve from the end of the rad so the rad system has no pressure (Have a jug, bowl and bucket handy ... or just use your drain off valves - mine need moving as they are no longer easily accessible.) I then checked the pressure on the expansion vessel with a car tyre pressure gauge (get on some steps and pear over the top right of the boiler. The vessel valve was a little loose, so I tightened it up, pumped it up (with a bike pump) checked and re-checked the pressure, refilled the system and started it all back up. Not had a murmur since.

I give this info freely and it's good, DIY advice

Thanks for the original help and i hope this helps someone else who was in the same boat as me (a small wooden one with only one paddle

 

[petit_pablo]

Probs worth keeping an eye on the pressure relief pipe. They have a nasty habit of not sealing properly once they have opened once.

 

[Agile]

And the winner is ChrisR, the expansion vessel has either split internally or simply lost its charge, diy if you can be trusted with a footpump!!

Are you sure ???

And see FAQ - Pressure Problems

Look and tell me where the FAQ can be found??? It is no longer on the list at the top of the page!

Its actually been moved to a locked thread about five subjects down!

Tony