A basic central heating question.

[Dave7]

Fairly modern system (maybe 4 years old)
Worcester combi boiler.
Pressure drops during c/h (winter) time, maybe every 8 weeks.
Had the installer out.
Had Worcester out.
Both spent a long time before declaring 'no problem'.
Anyway........my query.......
This morning the pressure had gone again.
I topped it up, reset it and all was well......for an hour. Then it went off again.
Pressure was full.
I pressed reset and it was ok.
Been ok for 3 hours now.
Was this just a blip or indicate a problem ??

 

[mistyoptic]

Is there water dripping from the pressure relief valve? Ours failed on our Worcester boiler last year with a bit of scale preventing it from sealing properly

 

[Dave7]

Is there water dripping from the pressure relief valve? Ours failed on our Worcester boiler last year with a bit of scale preventing it from sealing properly

Doesn't appear to be any leaks.
The Worcester engineer reckoned all was fine..

 

[bikingdad90]

Put the heating on full pelt, really high. Does the pressure rise to above normal levels (2bar+) ? If it does, go outside and check and the pipe and see if it is leaking. If it is then there is a good chance your expansion vessel has gone and need replacing.

 

[Lookrider]

If the engineer said it's all fine ..then please believe him
In the cold of night water will contract ( as do all things at lower temps ) because it contracts in a sealed system the volune of water gets "smaller" thus implying that there is a drop of pressure on the gauge
This is normal
If you put the heating on you will see the pressure will go up as the water heats up it expands putting pressure on the gauge ...switch it off and the pressure will drop again
Winter is not the best time to check pressures as it is fluctuating as the boiler tends to be in use more
The engineer will know a pressure drop due to a leak somewhere ..and he says it's fine
He will put some leak sealer in if you ask him too
get a compatible one for the heat exchanger within the boiler..again the engineer will advise compatibility

 

[bikingdad90]

A pressure increase or decrease staying between 1.0 and 2.0 is normal operating range and like @Lookrider says is to be expected.

If it is pushing over 2.0 bar then then you potentially have a problem. If the opposite happens and the pressure is slowly dropping to below 1.0 bar over time as opposed to tripping out due to over pressure then it is more than likely a leak/hole somewhere in the system.

Stupid point to check, you have closed off the pressurisation inlet after topping up haven’t you? If you have left it in the open position then it will let air into the system.

 

[Lookrider]

Worcester boilers have an "error" code that will be flashing in the display...the manual will tell you what that error code relates too
You can then tell your engineer who will know more about it ...and can then act on the repair if needed

 

[Dave7]

A pressure increase or decrease staying between 1.0 and 2.0 is normal operating range and like @Lookrider says is to be expected.

If it is pushing over 2.0 bar then then you potentially have a problem. If the opposite happens and the pressure is slowly dropping to below 1.0 bar over time as opposed to tripping out due to over pressure then it is more than likely a leak/hole somewhere in the system.

Stupid point to check, you have closed off the pressurisation inlet after topping up haven’t you? If you have left it in the open position then it will let air into the system.

Yes....it has 2 valves (no idea why) and I closed them both after topping up.

 

[Dave7]

Worcester boilers have an "error" code that will be flashing in the display...the manual will tell you what that error code relates too
You can then tell your engineer who will know more about it ...and can then act on the repair if needed

Thanks, will look at that.
Not seen any such messages but will check again.

 

[ColinJ]

Not seen any such messages but will check again.

These things are not subtle! My (different make) boiler lost pressure and shut down completely with F1 flashing on the display. F1 = loss of pressure fault.

My system holds its pressure for about 5 weeks, after which it slowly loses a little pressure over a few days, and then it suddenly loses the remaining pressure overnight. Very odd!

 

[cm2mackem]

Just had the same with my boiler, expansion vessel gone, most can be topped up with a bike pump, mine had a very small hole in the bladder, £40 to replace , shop around first quote was £90, 30 minute job no need to drain system but the old vessel will need draining before removing.

 

[cyberknight]

I am having the exact same issue , i rang up british gas home care and was told until the lockdown ends they will not even come out as i can repressurixe it to make it work even though i need to do it 3 times a day.

 

[newts]

What pressure are you filling up to?

 

[Dave7]

What pressure are you filling up to?

Not sure who your question was directed to??
I fill it till the needle stops.... which is on the green, about 3.
Incidentally it has, strangely, been working fine since. Maybe (hopefully) it was just a blip.
It will still need topping up every 3-4 weeks which, after reading other posts, I can live with.
With the old boiler I don't remember it ever having such a problem.

 

[PaulSB]

Not sure who your question was directed to??
I fill it till the needle stops.... which is on the green, about 3.
Incidentally it has, strangely, been working fine since. Maybe (hopefully) it was just a blip.
It will still need topping up every 3-4 weeks which, after reading other posts, I can live with.
With the old boiler I don't remember it ever having such a problem.

I guess we have the same or very similar boiler, a Worcester Bosch, though ours is 10 years old.

In that time I've topped it up once myself. It's been serviced annually and so the engineer may have topped it up then so no more than 10 times in 10 years.

Every 3-4 weeks sounds far too often to me. I would continue to try and find the problem and fix it.