Lots of air in Central Heating System

[amplecheeks]

Hi all

Turning to this forum as an act of last resort! Having some problems with my heating at home and would really appreciate any input.

Forgive my language, i'm not overly technical

I have a combi boiler at home (Potterton Combi 80), a sealed Heating system. The system is serviced regularly, the last in Oct 2012. Having said that, its reasonably old.

The problem we have is that air is continually making its way into the system. We drain the air out by bleeding the rads (usually its just the clothes rail upstairs as its the highest point in the house and the air tends to pool here).

Once I bleed the rads, the pressure in the system drops to zero, so I then top up the water via the filling loop. This returns the pressure to normal and the system works for a few hours. 3-4 hours later, the system is again full of air and not a lot of water once i bleed again.

As such i assume this means my closed system is taking in air somewhere and also losing water somewhere. I can't locate any leaks.

I'm told that some air can enter the system when i refill the water, but this doesn't explain where the water in my system is going.

Any ideas what the issue could be and how i could fix? I'm covered by a service agreement, but i'd like to have the knowledge to ensure they do the right thing.


Many thanks in advance

Luke

 

[75pete]

Does your system have the correct amount of inhibiter?
Pete

 

[amplecheeks]

not that i'm aware of. Just googled inhibitors...

I guess thats a good start?

 

[HERTS P&D]

Any pipes under the floor?

I suspect a leak!

Andy

 

[amplecheeks]

Any pipes under the floor?

I suspect a leak!

Andy

Hi Andy

yeah, some pipes. But not aware of any leaks. Nothing on first floor has penetrated down to ground floor (which i would expect given the volume of water loss) and nothing on the ground floor as i've had the boards up fairly recently. Would expect to smell some mould / damp too?

if it was a leak, would air usually enter the system too then?

 

[b13kal]

If the system is left with air in the rad with you not taking any air out, does the system loose pressure?

I think not and all it is that all your rads have air

Bleed all off them with someone at the boiler keeping the pressure at 1bar cold

Try this and report back .

If the pressure is dropping after what I said the. Go look for the leak.

Leak might be the blow off PRV

 

[dreadnoughtheating]

Does the 'air' that you vent smell of rotten-eggs?, if so it maybe hydrogen indicating a distinct cause..... (if you have no sense of smell, try 'igniting it')

Dreadnought

 

[easyflow]

Could be expansion vessel, it has a valve like a car tyre, press the valve and if water comes out thats the problem(s) but thats just somthing elde to look at.

 

[amplecheeks]

thanks for all the input.

There's no sulphuric smell. i couldn't find any leaks. Thankfully we are semi redecorating downstairs (as in, when we get the money!) so lifting a few boards wasn't an issue. Definitely no leak in the pipes.

Eventually arranged an engineer to come out as we had cover. He found the flow switch to be faulty, causing overheating in the boiler, hence lots of steam vending out both through the proper valve and internally.

Have left the heating on all day for a few days and no issues at all with air in pipes or pressur eloss so touchwood all seems to be in order.

Thanks again.

oh, and i've added some inhibitor this time!

 

[bolshy]

So your boiler was overheating, and you decided to leave that part out - LOL.

 

[amplecheeks]

So your boiler was overheating, and you decided to leave that part out - LOL.

leave it out? thought i made it pretty clear in the first poist that i'm a bit of a novice. I wasn't aware it was overheating.