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SteveG
New to this forum so will try and be as clear as I can in my explanation of the problem(s)...Sorry about the long winded narrative!
I have a Vaillant 831 Combi boiler which was fitted in August 2011 along with all new pipes and radiators. Whenever the CH comes on, the pipes in the ceiling make very loud ticking sounds which I have to admit I've left for too long to address. I was thinking that I had a lot of air in the system as the top half of the bathroom towel rail has been cold for as long as I can remember.
I decided to bleed the radiator (Sunday morning) and I let air out so my suspicions were right. I checked the pressure of the boiler (pressing the "-" button) and topped up the water to show about 1.5bar using the installed filling loop. Now I come to think of it, the analogue pressure gauge has always been in the very low part of the dial when cold - even though the boiler has always fired up when needed.
Problem 1. The analogue pressure gauge now goes into the red when CH is turned on (the digital reading climbs to 2.3bar which is an increase of 0.8bar so I switch the system off). When using DHW, the pressure increases by about 0.3bar and stabilises. Because of the potential problem, I've kept the CH off and when I checked the digital pressure gauge after the system had been cold for over 8 hours, it read 1.2bar (clearly a loss somewhere).
Note: Shortly after topping up the system on Sunday, I pressurised the expansion vessel to approx 0.9bar.
Problem 2. When checking the cold system Monday morning (pressure was 1.2bar), I switched on CH to see what it would do. Whilst the boiler was starting, I tied 2 clear sandwich bags over the outside pipes (condensate and PR pipe). Ultimately, the pressure rose beyond 2.3bar again so I shut off the boiler. When I checked the plastic bags, the PR pipe bag was empty but the condenstate bag was very full with clear water which surprised me as the water in the system which came out when I bled the towel rail was dark.
I have put a fresh bag over the condensate pipe to see if the leak is collected here with the system turned off - only just done this so can't report findings yet.
I see several challenges here:
A. Pressure is being lost overnight when the system is cold - does this suggests a leak somewhere either with the boiler or with the pipe work / rads / TRVs?
B. Pressure increases too much when the system fires up - does this suggest either air or water is getting into the system when the CH is fired up or might this be a problem with the expansion vessel?
Thanks in advance for any advice you can give me.
Steve
I have a Vaillant 831 Combi boiler which was fitted in August 2011 along with all new pipes and radiators. Whenever the CH comes on, the pipes in the ceiling make very loud ticking sounds which I have to admit I've left for too long to address. I was thinking that I had a lot of air in the system as the top half of the bathroom towel rail has been cold for as long as I can remember.
I decided to bleed the radiator (Sunday morning) and I let air out so my suspicions were right. I checked the pressure of the boiler (pressing the "-" button) and topped up the water to show about 1.5bar using the installed filling loop. Now I come to think of it, the analogue pressure gauge has always been in the very low part of the dial when cold - even though the boiler has always fired up when needed.
Problem 1. The analogue pressure gauge now goes into the red when CH is turned on (the digital reading climbs to 2.3bar which is an increase of 0.8bar so I switch the system off). When using DHW, the pressure increases by about 0.3bar and stabilises. Because of the potential problem, I've kept the CH off and when I checked the digital pressure gauge after the system had been cold for over 8 hours, it read 1.2bar (clearly a loss somewhere).
Note: Shortly after topping up the system on Sunday, I pressurised the expansion vessel to approx 0.9bar.
Problem 2. When checking the cold system Monday morning (pressure was 1.2bar), I switched on CH to see what it would do. Whilst the boiler was starting, I tied 2 clear sandwich bags over the outside pipes (condensate and PR pipe). Ultimately, the pressure rose beyond 2.3bar again so I shut off the boiler. When I checked the plastic bags, the PR pipe bag was empty but the condenstate bag was very full with clear water which surprised me as the water in the system which came out when I bled the towel rail was dark.
I have put a fresh bag over the condensate pipe to see if the leak is collected here with the system turned off - only just done this so can't report findings yet.
I see several challenges here:
A. Pressure is being lost overnight when the system is cold - does this suggests a leak somewhere either with the boiler or with the pipe work / rads / TRVs?
B. Pressure increases too much when the system fires up - does this suggest either air or water is getting into the system when the CH is fired up or might this be a problem with the expansion vessel?
Thanks in advance for any advice you can give me.
Steve
