21 Feb 2006
Reaction score
United Kingdom

I was wondering if anyone could point me in the right direction or offer some advice please?

My Problem:

About a week ago my heating stopped working, so I called a friend who's a plumber to have a look. He replaced, sorry my terminology isn't great, but he replaced the pump. Job sorted, heating, hot water working fine. Then a few days ago a neighbor noticed that there was a leak in the garage below our house, so I called my plumber friend back, he checked the boiler and confirmed that there is still pressure so the leak can't be caused by the boiler. Then the central heating stopped working again. The hot water is working its just there is no central heating in the entire house.

I then looked through the yellow pages for local plumbers, I had 3 different people telling me the same thing, "It’s got to be the pump"! Having told them that I just got that replaced and that a neighbor noticed a leak one of the guys turned of the mains water supply to my house to see if that would stop the leak.

So now, when the water supply is off, the central heating comes on and there is no leak in the garage below our house. When the water supply is turned on the central heating doesn't work but there is hot water and there is a leak in the garage.

I thought that maybe this is 2 separate problems we are having:

1. Pump was incorrectly installed. (explains why there is no heating)

2. The leak is coming from another pipe from our house (nothing to do with the boiler because it has maintained pressure.)

I can't seem to see the link between having the main water supply turned off in order for the central heating to work & to stop the leak in the garage.(maybe its coming from another pipe, hence turning the main water supply off stops this leak) But turning it on would mean we have hot water (boiler working fine) but there’s a leak in the garage and no central heating.

Could anyone shed some light on this matter?

Sponsored Links
What sort of boiler is it? Is it a sealed system? Is there a chance that on topping up the system, the plumber has left the fill up loop 'open' and the leak in the garage is the blow-off pipe?

Just a thought?

Sorry, i forgot to mention that the boiler is a Potterton Puma 80, not too sure if thats how its spelt. I'm at work at the mo, will add another post to clarify when i get home home tonight.
What is probably happening is a water leak on your hot water between blr & taps (hence leak in garage) which will also explian why htg wont work as dhw has priority
Sponsored Links
If what wearelands is saying is right, the boiler will be constantly firing to heat the hot water.

I'm assuming a Potterton Puma 80 is a combi. If it is a combi, I'd still check that the Filling loop (silver braided pipe about a foot long usually under the boiler) hasn't been left open. If it has, I hope you're not on a water meter!

There is probably a leak on the hot pipework between boiler and taps but the leak is below the threshold required to activate the flow switch hence boiler doesn't fire up.

Normally a leak small as a drop per second will stop the heating working on the Puma's due to the wax capsule in the diverter valve not heating up.

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.

Are you a trade or supplier? You can create your listing free at DIYnot Local