New house plumbing problems

[gotomuzzi]

Hi all, new house has an oil boiler in the utility and an unvented cylinder in the room above it. About a week ago I noticed water trickling out of a drain pipe outside, when I went up to the tank I could see water flowing slowly through the tundish from the PRV up above it. Pulling the PRV knob stopped the flow so I thought that was the end of it.

Girlfriend phoned me yesterday to say water coming out of the tundish and through the ceiling, I asked her to switch HW off and run the hot tap for a while and it stopped the leak.

So I’ve got two problems, water passing PRV and tundish drain blocked. Am I right in thinking if the expansion vessel doesn’t have air in it then that might cause the PRV to pass water? But would that be more than a drip?
It hasn’t been that could lately so I don’t think the drain can be frozen, I’m not sure how else the drain could have become blocked though. Would a plumbers drain snake from the outside up be the best way to go?

I’m away with work for another week and if needs be I’ll get a plumber in but if its something I can fix myself then I would prefer to do that when I get back. Any help would be greatly appreciated.

[gotomuzzi]

silversurfer1 said:

gotomuzzi said:

Hi all, new house has an oil boiler in the utility and an unvented cylinder in the room above it. About a week ago I noticed water trickling out of a drain pipe outside, when I went up to the tank I could see water flowing slowly through the tundish from the PRV up above it. Pulling the PRV knob stopped the flow so I thought that was the end of it.

Girlfriend phoned me yesterday to say water coming out of the tundish and through the ceiling, I asked her to switch HW off and run the hot tap for a while and it stopped the leak.

So I’ve got two problems, water passing PRV and tundish drain blocked. Am I right in thinking if the expansion vessel doesn’t have air in it then that might cause the PRV to pass water? But would that be more than a drip?
It hasn’t been that could lately so I don’t think the drain can be frozen, I’m not sure how else the drain could have become blocked though. Would a plumbers drain snake from the outside up be the best way to go?

I’m away with work for another week and if needs be I’ll get a plumber in but if its something I can fix myself then I would prefer to do that when I get back. Any help would be greatly appreciated.

yes the expansion vessel being low can cause more than just a drip as the cylinder heats up.

Turn off main open hot taps until water stops, open prv keep open if poss. Attach foot pump to valve on expansion vessel and pump up to 3 bar close prv and turn main on and vent hot taps. You want 3 bar in expansion whilst 0 bar on outlet so keep taps and or prv open

the tundish pipe work probably is not blocked you can test this by carefully pouring water down it. Often what happens is the water is running to fast to get it all in the tundish and some makes its way down the side of the pipe rather than inside the pipe \(crap design)

Good luck

ss

Thanks, that gives me some things to try when I get back.

[gotomuzzi]

Just to update this thread and thank everyone again. Got back today and silversurfer was right the tundish pipe wasn’t blocked at all it just can’t handle much flow and dribbles down the pipe. Next I did as suggested and drained the hot water and checked the expansion vessel - no charge at all so I have pumped that up to 3 bar with my foot pump which was easier said than done! So now I’m going to have a beer and watch the tank like a hawk while it heats up.

Cheers
Chris

Edited by gotomuzzi on Tuesday 15th January 16:51

[gotomuzzi]

Well I woke up this morning to find it has leaked overnight. I’ll check the expansion vessel again to make sure it hasn’t lost its charge. Failing that it’s probably time to get a plumber in.

[gotomuzzi]

Quite difficult to get it all in shot, Is that the pressure reducing valve underneath the expansion vessel? Not the neatest of plumbing jobs but I think the house has had a few additions over the years.

[gotomuzzi]

Bit late in updating this thread but after some instructions from a plumber we worked out it was the combination valve that was causing the leak so this has been changed and touch wood no leaks since.