Halsead Ace He 24 Is slow drop of pressure normal?

[sussexgirl]

Hi, new to this forum and hoping for clarification on a slow loss of pressure. Boiler 5yrs old but has been losing pressure virtually since installed. Drops from 1 bar to 0.25 bar over 4 - 8 weeks of central heating use in the winter. Called Halstead engineer while under warranty, who said nothing wrong with boiler - must be slow leak in pipes/radiators. Over the last 5 years I have never been able to detect even the tiniest leak in pipes or radiators or floors or ceilings. And no dripping from overflow pipe to outside either. So every couple of months I have to climb into the loft and allow water into the boiler for a few seconds to raise pressure up to 1 bar again.

The pressure drop has not got worse over the 5 yrs I've had the boiler but I do worry that I'm diluting the rust inhibitor or that the pressure loss may increase one day.

So this week I called another gas guy to check out the boiler. He could find no leaks in the boiler and said that ALL combi boilers need toping up with water at least once a year. Is this correct????? Am I worrying over a tiny loss of pressure which is simply normal and i will have to just keep toping up with water???

I asked the guy to please check everything and he said it could be the expansion vessel. So he checked its pressure was OK and he released air from it and no water came out, so that must be OK.

Note that there is very little loss of pressure over the summer when the central heating is not on - the boiler is only used for hot water in summer and rarely the cental heating.

Ideas anyone?? Is this magnitude of water pressure drop normal? If not, what could be the cause?? Thanks for any advice/suggestions. SG

 

[M.Joshi]

I do worry that I'm diluting the rust inhibitor or that the pressure loss may increase one day.

You are quite right in noting that the inhibitor will get diluted every time you top-up the system pressure. If you are having to do this continuously, you should also be adding inhibitor.

Most boilers will have a PRV (Pressure Relief Valve) fitted which opens when the pressure exceeds a pre-determined level. If the PRV is letting by, it can be a cause of loss in system pressure but you said that you have already checked this.

The slow loss in pressure could be something as simple as a weep from a radiator valve. The water evapourates when the radiator heats up - hence you wouldn't notice it. If the pipes to the radiators are copper, have you noticed any green (oxidisation) stains around the valves?

 

[Dotty]

You shouldn't be too concerned about an over pressure situation as most boilers will have a PRV (Pressure Relief Valve) fitted which opens when the pressure exceeds a pre-determined level. If the PRV is letting by, it can be a cause of loss in system pressure but you said that you have already checked this.

What a dangerously irresponsible piece of advice! You are clearly NOT in the trade! That is in the same vein as telling someone not to check the car brakes because they've got a seatbelt and airbags. You don't have a clue!

Sussexgirl. Tape a clear plastic bag round the safety valve outlet outside, this will give you a better indication as to whether it's passing or not. Also are you bleeding a radiator on the odd occasion?

 

[M.Joshi]

What a dangerously irresponsible piece of advice! You are clearly NOT in the trade! That is in the same vein as telling someone not to check the car brakes because they've got a seatbelt and airbags. You don't have a clue!

I have amended my previous reply as I misread the OP. What I meant to say is that if the pressure were to increase and the user was not aware of it, there are mechanisms in place within most boilers to deal with this situation. By no means was I advocating the user purposely overpressurises the system to test the PRV or expansion vessel. Neither was I suggesting that they ignore the pressure gauge/reading.

 

[GrahamM]

If as you say has been loosing pressure in this manner from day one, it certainly points to a leak in the system somewhere.
All it takes is a steady drip from some fitting to drop the pressure over a number of weeks.
If you have checked all you can see; is there any pipework under the ground floor that you cant?
As a last resort, talk to an engineer about adding leak sealer to the system.