Repressuring system multiple times

[richardstephens36]

Hi all

I have moved into a house with a combi boiler. The heating system worked fine for 2 weeks (apart from some tops of radiators being cold). I decided to bleed the system, and let a lot of air out. As expected, the system lost pressure. I repressurised the system to 1.5 bar at the boiler. Since then, pressure has kept dropping, and I have had to repressurise many times (maybe 20).

There are no signs of any leaks and I have checked that the bleed valves are all closed. It does seem to be beginning to hold pressure for longer, but still requires repressurising.

Is it normal for it to require repressuring so many times?

Many thanks,
Richard

 

[rpm]

No, best get somebody to investigate why.

 

[Rob Foster]

Hi all

I have moved into a house with a combi boiler. The heating system worked fine for 2 weeks (apart from some tops of radiators being cold). I decided to bleed the system, and let a lot of air out. As expected, the system lost pressure. I repressurised the system to 1.5 bar at the boiler. Since then, pressure has kept dropping, and I have had to repressurise many times (maybe 20).

There are no signs of any leaks and I have checked that the bleed valves are all closed. It does seem to be beginning to hold pressure for longer, but still requires repressurising.

Is it normal for it to require repressuring so many times?

Many thanks,
Richard

most pressurised systems need topping up to 1.5 bar every 2 months or less often. You do not state how often you need to do this, the 20x is over what period ? centralheatking

 

[townfanjon]

Top up to 1 bar , when cold , very important , not when its hot .
Top up maybe another twice , if you are still doing it after that , you sound like you have a leak , could be boiler , or system.

 

[rpm]

Hi all

I have moved into a house with a combi boiler. The heating system worked fine for 2 weeks (apart from some tops of radiators being cold). I decided to bleed the system, and let a lot of air out. As expected, the system lost pressure. I repressurised the system to 1.5 bar at the boiler. Since then, pressure has kept dropping, and I have had to repressurise many times (maybe 20).
Is it normal for it to require repressuring so many times?

Many thanks,
Richard

most pressurised systems need topping up to 1.5 bar every 2 months or less often. You do not state how often you need to do this, the 20x is over what period ? centralheatking

"I haved moved" makes it sound pretty recent Rob however point taken.

 

[rpm]

Edit

 

[king of pipes]

Leakage somewhere would be my guess . Kop

 

[richardstephens36]

Many thanks to everyone for the replies.

The 20 times refers to a period of about 5 days.

My fear was that there is a leak somewhere. I will have to get someone in.

My only other thought was whether the pressure gauge on the front of the boiler is giving a false reading (i.e. it is faulty). When I first bled the radiators, the boiler stopped functioning and displayed an error due to the low pressure, which is when I began repressurising.

However, I have now stopped repressurising the system, and despite a low reading on the gauge, the system is still working with no problem. Could it be that the pressure in the system is actually higher than the gauge is reading, so that when I am repressurising I am actually overpressurising?

Unfortunately I don't know what it was reading when I first moved in before bleeding the radiators.

Many thanks again
Richard

 

[chris watkins]

Yes gauges are often inaccurate.
What is the boiler ?
Have you checked the safety valve discharge pipe which is normally outside behind the boiler is it wet?

 

[island fling]

Maybe worth getting a service done on your boiler. It may well be an expansion vessel issue - might need re-pressurised, your gauge may be faulty so maybe over pressuring as you say & might be blowing off out your pressure relief valve.
Could be a few issues but if you have just moved in then getting a service will be worth while anyway.

 

[richardstephens36]

Thanks for all of your help.

Annoyingly the discharge pipe exits the house in a place that's very awkward to get to. I had a look from afar and I couldn't see any signs of water but that doesn't mean that there isn't any.

Sounds like a service might be the best way go.

Thanks!
Richard

 

[island fling]

Thanks for all of your help.

Annoyingly the discharge pipe exits the house in a place that's very awkward to get to. I had a look from afar and I couldn't see any signs of water but that doesn't mean that there isn't any.

Sounds like a service might be the best way go.

Thanks!
Richard

If it has an air gap underneath (should have) then on a dry day put a cup or something below it to see if it catches any water.
Make sure the expansion vessel pressure is checked & re-pressurised if needed. I’ve gone to many boilers that are dropping pressure that have been ‘serviced recently’ & I find the expansion vessel to be at fault.

Worth checking if any of these lads on here are in your area. All seem like very good knowledgeable lads.

 

[Rob Foster]

usual suspect places are the Prv, a small vapourising leak inside boiler, small impossible to detect beads of water on rad valves, or mechanical joints which evaporate undetected. You could put a small army into an average home and not detect these type leaks. Get an MFD from Flowflex diy fit in 5 mins problem mitigated
Rob Foster aka centralheatking

 

[chris watkins]

usual suspect places are the Prv, a small vapourising leak inside boiler, small impossible to detect beads of water on rad valves, or mechanical joints which evaporate undetected. You could put a small army into an average home and not detect these type leaks. Get an MFD from Flowflex diy fit in 5 mins problem mitigated
Rob Foster aka centralheatking

The 20 times refers to a period of about 5 days.

It is not going to be a small leak is it Rob ? and fitting something that just keeps adding fresh water to a system is not good advice either, the system will quickly be full of corrosion.
Maybe not the correct time for pushing a product you have been involved in?

 

[Aire]

An mfd is only masking the problem though. To be honest, the theory of an mfd is better than the practicality of them. Pressure loss on a system can instantly show a leak on a system, if we went round fitting mfd's on everyone's systems then the first sign of a leak our customers will get is damp rising up the walls. Let's say a radiator burst while the customer was away, it's going to cause damage regardless but on a sealed system there's only so much water that can drain over the customers floor, if that same customer had an mfd fitted, they would come home to swimming pool. Sorry, just my opinion on them.

Also agree with Chris's comment on the constant dilution of inhibitor, just another downside to using them.

 

[richardstephens36]

I have just noticed today a few drops of coppery water come from the boiler. Looking up where it comes from there is a sludgy green trace on the inside. I guess this could be the source of the problem. Seems like not very much water compared with the amount that I've been topping up, but perhaps it is all evaporating. Time to get someone in !


Boiler is Baxi 105e

 

[richardstephens36]

Although it still strikes me as being strange that the boiler should develop a leak at the moment I bleed the radiators, when it had been working fine for 2+ before hand

 

[chris watkins]

Could be the AAV in the boiler / system operated due to that air & has not sealed back up, it can be a lot of things as mentioned by others & they can be in combination.

 

[Rob Foster]

An mfd is only masking the problem though. To be honest, the theory of an mfd is better than the practicality of them. Pressure loss on a system can instantly show a leak on a system, if we went round fitting mfd's on everyone's systems then the first sign of a leak our customers will get is damp rising up the walls. Let's say a radiator burst while the customer was away, it's going to cause damage regardless but on a sealed system there's only so much water that can drain over the customers floor, if that same customer had an mfd fitted, they would come home to swimming pool. Sorry, just my opinion on them.

Also agree with Chris's comment on the constant dilution of inhibitor, just another downside to using them.

no swimming pool it has flood protection built in and is a temporary patch never a permenant solution centrakheatking