Boiler Pressure Drop

[orbitaleccentric]

When this last happened I did consult this Forum and although the info didn't quite help directly, I managed to sort it out.

The boiler is a Vailllant ecotec plus 831, about 2.5 years old connected to a system that is probably at least 10 years old - lots of Hep2O.

After working perfectly for about 2 years all of a sudden the boiler was losing pressure on a daily basis - usually at night. I would top up the boiler everyday to get it to work. I checked all the visible pipework & controls and the radiators. One rad value had a minute leak which I replaced. The daily pressure drop continued.

I then decided to inspect the pressure relief value - I had noticed that the end of the discharge pipe was damp. The inside of the valve was dull. I rinsed it out and re-installed it. I re-pressurized the system and it worked perfectly. That was 6 months ago.

The problem has returned. I decided that it must be the PRV so ordered a new one and installed it. When I removed the existing PRV I noticed black debris had been deposited in the valve (the system had been flushed when the boiler was put in).

The system water was clear.

The problem has persisted with the new PRV!

The system is regularly maintained.

Anyone got any ideas as to what is going on?

 

[ChrisR]

AH well, the technical term, know to us wots in the trade, is a leak.
Turn boiler off and let it cool.
SHut the isolating valves on the flow and return
See what happens to the pressure on that damned silly gauge with no numbers(?)
If it drops o'ernight, the leak's in the boiler.
If it doesn't drop until you reopen the valves, it's the pipe/rads. CHeck the rad valves again - it's likely to be them, or a pushfit joint

 

[orbitaleccentric]

Thanks 4 that ChrisR.

I found the FAQs about Boiler Pressure and checked the pressure of the PV - no water came out but neither did air!!

I guess that's a major contributing factor.

 

[gas4you]

Should be charged to 0.75 bar on these.

Once done and system repressurised I would recomend running the P0 purge program.

Always check the exact system pressure by pressing the'-' button.