Central Heating Leak

50Twuncle

We are losing water in our central heating system - It needs topping up way too often (before anyone says "but it is summer" - I know - but last winter it did.....)
Anyway - the boiler is a 6 year old Worcester Combi - and needs regular topping up (filling loop permanently connected)
I estimate 10 secs worth - weekly - so several litres
We assume that there is a small leak in a pipe - somewhere in the system ?
We have just had a plumber out for a look and he recommends some form of leak sealant - poured in to the system (like radweld in cars)
My worry is that this sealant may cause problems with the pump

Any advice welcome.
ie) Would you spend £15 on something unknown, but this may only be a temporary cure ?

Myser

Firstly, you need to try and locate the leak before adding leak sealant. Some boiler manufacturers don't recommend it.

Was the person you spoke to a Gas Safe Registered plumber? It's unusual to recommend leak sealant without checking all possible causes of a leak first.

Have a look at this recent thread for possible causes/areas to look:

https://forums.moneysavingexpert.com/discussion/4688713

diywhynot

Leak sealant is the cowboy's friend. Get someone in who can diagnose and resolve.

50Twuncle

Myser wrote: »

Firstly, you need to try and locate the leak before adding leak sealant. Some boiler manufacturers don't recommend it.

Was the person you spoke to a Gas Safe Registered plumber? It's unusual to recommend leak sealant without checking all possible causes of a leak first.

Have a look at this recent thread for possible causes/areas to look:

https://forums.moneysavingexpert.com/discussion/4688713

Yes - he is Gas Safe registered !!
What concerns me is putting this gunk into a pump !!

diywhynot

50Twuncle wrote: »

Yes - he is Gas Safe registered !!
What concerns me is putting this gunk into a pump !!

You should be concerned. His 'fix' is a bodge. Many places in a CH system where pressure can be lost, you need to find out where.

Mr_Ted

:eek:Dont use a leak sealant, its a bodge and WILL cause other problems:eek:

Find the leak, it may only be small

In summer when the heating is OFF is the time when most leaks occur, or show themselves, as the ambient air is warm and the water is colder, and the pipework expands with the external heat whilst the water doesn't as it isn't heating the system equally;)
The only problem is the ambient air temperature evaporates the leaking water making it harder to find, so check all joints, particularly on the rads as this is the most common place for leaks to occur;)
Equally in winter the leaks get evaporated due to system being hot, so check thoroughly;)

keystone

50Twuncle wrote: »

Yes - he is Gas Safe registered !!
What concerns me is putting this gunk into a pump !!

What should concern you is putting this gunk into anything. Just don't.

Cheers

50Twuncle

Thanks everyone - it looks as if it is "bite the bullet" time
Carpets and Floorboards are going to have to come up
Maybe it is worth replacing the whole system - pipes are 20 + years old and the radiators are a similar age too
What sort of cost am I looking at for a 3 bed semi ?

macman

Hold on! Before anything has to 'come up', have you checked the overflow pipe from the PRV for discharge? That''s one of the most common causes of constant top ups, becuse the PRV has a bit of dirt under it and then won't reseat again. Then check the expansion vessel.
There's no reason whatsoever to think that you need to replace any rads or pipework.
If you RGI didn't first check the PRV and then the EV then he is clueless.
Leaks on the CH circuit should be the last thing to be checked.

Myser

Before you go lifting up floorboards, check the Pressure Relief Valve (PRV) discharge pipe and Expansion Vessel (EV) as mentioned by macman.

Then, inspect all the radiator valves and bleed nuts carefully making sure they are tight.

If your radiator pipes are copper, look for oxidisation (green marks) on any pipes.

50Twuncle

macman wrote: »

Hold on! Before anything has to 'come up', have you checked the overflow pipe from the PRV for discharge? That''s one of the most common causes of constant top ups, becuse the PRV has a bit of dirt under it and then won't reseat again. Then check the expansion vessel.
There's no reason whatsoever to think that you need to replace any rads or pipework.
If you RGI didn't first check the PRV and then the EV then he is clueless.
Leaks on the CH circuit should be the last thing to be checked.

The expansion vessel does need regular pressurising but according to the "experts" who fitted it - who are Worcester engineers - that is not the cause of the "leak" - hence the "second opinion" this afternoon !!
So you are saying that it may be the PRV ?