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I had a Vailant ecotec plus 838, installed end of June 2016. No problems with pressure at all until this summer (end of) when we finished a rear extension.
N.B Central heating pipes on ground floor are approximately 30-80cm below the finished floor level as we have a raised concrete beam and block floor and then 15cm on insulation then 7cm of screed and then tiles.
Changes to central heating were:
Boiler moved approxImately 100cm
One radiator removed (pipes removed also)
One radiator added in downstairs WC
One towel rail moved 20cm
Wet underfloor heating added to extension and some of original area (Triple layered Aluminium PE-Xb/AL/HDPE Pipe) 2 loops (each no more than 100m)
We noticed after the extension was finished (end of September when we started turning the heating on that after two weeks the pressure dropped below 0.8 bar so the boiler cut off. We topped it up a couple of times and removed all air from radiators but it kept happening.
The pressure never went above 3 bar when the heating was on. It went up around 0.5 bar when the heating was full on.
I turned off the valves for the underfloor heating and the pressure kept on falling, so I am assuming that the underfloor heating is not the problem and I guess this can be further confirmed as it was pressurised to around 6-7 bar when the screed was put over it and there were no obvious leaks detected.
Eventually after a couple of months it had to be re-pressurised every 4-5 days so I called Vailant and they sent an engineer (covered by 5 year warranty) he could not find any obvious signs of a leak (went outside of property and I also checked the overflow pipe was not leaking by placing a plastic bag over it for 24 hours and there was no water inside the bag. The engineer told me he could not do a pin test as the temperature was around 40 degrees on dial and I said nobody told me I could not use the heating (it was now November and cold). The engineer said Vailant would replace the heat exchanger and they did the following week.
A few days later there was water leaking from the boiler itself (approx 1-1.5 litres over a 12 hour period (I did turn the heating off) and again I called Vailant and the engineer came the same day and he noticed that after the heating exchanger was replaced the rubber seal near one copper pipe to the heat exchanger was still the old one and said he would have normally changed that and he did and no subsequent leaks from the boiler itself. The Vailant engineer also closed the two valves below the boiler and did a test with some machine for 7 minutes and opened them up and there was no drop in pressure. The engineer told me there isn't a leak in the central heating. Subsequently i still had to top up the pressure every 4-5 days.
I then called a leak detection company who sent me a gas safe leak detection specialist who drained the entire system and filled it with gas and over a 40 minute period there was no escape of gas nor could any be detected when the pipes are below the ground on the ground floor. He told me that he is extremely sure that there is no actual leak in the central heating. He told me it could be the expansion vessel and any excess water removed from the system would just go through the condensing pipe so I would not physically see any leaking water.
After this engineer left the boiler seemed fine for around 10-12 days with no pressure loss then all of a sudden by day 14 I had to re-pressurise the system, and again 2 days later. The only different thing that was done to my boiler was the leak detection guy turned around one of the two port valves (the one for the central heating - as it was the wrong way around and we were experience banging noise whenever it closed, but this stopped). Also around day 12 I changed the temperature for the water for the underfloor heating from the manifold to 50 degrees C from 45 degrees C. Could this have explain anything?
Is there anything that I have missed or can anyone suggest anything else?
The leak detection engineer said I can wait until the weather is much warmer and do a power flush and see what happens and also turn the valves at the bottom of the boiler with an allen key and leave it closed for a week and then turn them and see if the pressure massively drops, which would provide concrete proof tha there was a leak at all in the central heating.
I think I should next call Vailant and inform them of the gas test and ask if they can change the expansion vessel as maybe this is the issue?
N.B Central heating pipes on ground floor are approximately 30-80cm below the finished floor level as we have a raised concrete beam and block floor and then 15cm on insulation then 7cm of screed and then tiles.
Changes to central heating were:
Boiler moved approxImately 100cm
One radiator removed (pipes removed also)
One radiator added in downstairs WC
One towel rail moved 20cm
Wet underfloor heating added to extension and some of original area (Triple layered Aluminium PE-Xb/AL/HDPE Pipe) 2 loops (each no more than 100m)
We noticed after the extension was finished (end of September when we started turning the heating on that after two weeks the pressure dropped below 0.8 bar so the boiler cut off. We topped it up a couple of times and removed all air from radiators but it kept happening.
The pressure never went above 3 bar when the heating was on. It went up around 0.5 bar when the heating was full on.
I turned off the valves for the underfloor heating and the pressure kept on falling, so I am assuming that the underfloor heating is not the problem and I guess this can be further confirmed as it was pressurised to around 6-7 bar when the screed was put over it and there were no obvious leaks detected.
Eventually after a couple of months it had to be re-pressurised every 4-5 days so I called Vailant and they sent an engineer (covered by 5 year warranty) he could not find any obvious signs of a leak (went outside of property and I also checked the overflow pipe was not leaking by placing a plastic bag over it for 24 hours and there was no water inside the bag. The engineer told me he could not do a pin test as the temperature was around 40 degrees on dial and I said nobody told me I could not use the heating (it was now November and cold). The engineer said Vailant would replace the heat exchanger and they did the following week.
A few days later there was water leaking from the boiler itself (approx 1-1.5 litres over a 12 hour period (I did turn the heating off) and again I called Vailant and the engineer came the same day and he noticed that after the heating exchanger was replaced the rubber seal near one copper pipe to the heat exchanger was still the old one and said he would have normally changed that and he did and no subsequent leaks from the boiler itself. The Vailant engineer also closed the two valves below the boiler and did a test with some machine for 7 minutes and opened them up and there was no drop in pressure. The engineer told me there isn't a leak in the central heating. Subsequently i still had to top up the pressure every 4-5 days.
I then called a leak detection company who sent me a gas safe leak detection specialist who drained the entire system and filled it with gas and over a 40 minute period there was no escape of gas nor could any be detected when the pipes are below the ground on the ground floor. He told me that he is extremely sure that there is no actual leak in the central heating. He told me it could be the expansion vessel and any excess water removed from the system would just go through the condensing pipe so I would not physically see any leaking water.
After this engineer left the boiler seemed fine for around 10-12 days with no pressure loss then all of a sudden by day 14 I had to re-pressurise the system, and again 2 days later. The only different thing that was done to my boiler was the leak detection guy turned around one of the two port valves (the one for the central heating - as it was the wrong way around and we were experience banging noise whenever it closed, but this stopped). Also around day 12 I changed the temperature for the water for the underfloor heating from the manifold to 50 degrees C from 45 degrees C. Could this have explain anything?
Is there anything that I have missed or can anyone suggest anything else?
The leak detection engineer said I can wait until the weather is much warmer and do a power flush and see what happens and also turn the valves at the bottom of the boiler with an allen key and leave it closed for a week and then turn them and see if the pressure massively drops, which would provide concrete proof tha there was a leak at all in the central heating.
I think I should next call Vailant and inform them of the gas test and ask if they can change the expansion vessel as maybe this is the issue?
