Leaky tundish - advice please!

phil235 · Dec 6, 2019

I have the usual problem of a dripping expansion relief valve on the cold supply to an unvented cylinder, which is shortly to be replaced (the valve) by a G3 plumber. What made it worse is that the drip (which has become an almost continuous dribble) tends to run down the inside of the tundish rather than dropping straight down, and has leaked between the (supposed) seal between the tundish and the 22mm pipe below. Ceiling below now marked and paint bulged away from woodwork. The nut securing the tundish to the pipe is tight. It's a cheapo-looking plastic job, 85mm high. Can someone recommend a better tundish, please?

king of pipes · Dec 7, 2019

A hot tun is a better option or Teslatun the outlet size is increased , 100% splash proof is hard to achieve but fabric damage is not acceptable get your G3 qualified engineer to check the expansion vessel . Kop

SJB060685 · Dec 7, 2019

That dribble can be a few things. Like kop said get your engineer asap. If he knows his stuff then theres no further need for us to comment. Obviously this being an unvented system I'm reluctant to tell you what to do. I hope you understand

phil235 · Dec 7, 2019

phil235 said:
I have the usual problem of a dripping expansion relief valve on the cold supply to an unvented cylinder, which is shortly to be replaced (the valve) by a G3 plumber. What made it worse is that the drip (which has become an almost continuous dribble) tends to run down the inside of the tundish rather than dropping straight down, and has leaked between the (supposed) seal between the tundish and the 22mm pipe below. Ceiling below now marked and paint bulged away from woodwork. The nut securing the tundish to the pipe is tight. It's a cheapo-looking plastic job, 85mm high. Can someone recommend a better tundish, please?

Thanks for this reply. Watching the thing again, I've realised that the leak from the tundish is the water drip running down the inside slope of the upper half of the (Altecnic) tundish and then out over the side (at the back, not noticed before) - nothing to do with the joint to the 22mm pipe. (Isn't surface tension wonderful?) My guess is that the 15mm pipe doesn't protrude sufficiently into the tundish for the drips to fall straight down. Temporary trial fix: a couple of little blobs of Fernox LS-X on the rim, so that the drips go inside rather than outside (seems to be working); proper fix: a taller tundish when my G3 plumber comes to replace the valve.
[automerge]1575734490[/automerge]

king of pipes said:
A hot tun is a better option or Teslatun the outlet size is increased , 100% splash proof is hard to achieve but fabric damage is not acceptable get your G3 qualified engineer to check the expansion vessel . Kop

Thanks for this advice. I can see a Hotun is a better shape, although don't need the anti-pong protection (one more thing to go wrong...) as the outlet runs to outside, not into a drain/soil pipe. But, ref my reply above, the Hotun's taller so will provide for some inlet pipe protrusion. Yes, will ask re. expansion vessel.
[automerge]1575734773[/automerge]

SJB060685 said:
That dribble can be a few things. Like kop said get your engineer asap. If he knows his stuff then theres no further need for us to comment. Obviously this being an unvented system I'm reluctant to tell you what to do. I hope you understand

Thanks. Yes - quite understood. Don't worry - I wouldn't fiddle with anything beyond checking that the tundish bottom nut was tight.

SJB060685 · Dec 7, 2019

Not fiddling is the right choice. See if your quick fix holds and wait for your G3 specialist to attend. The problem you're experiencing can be caused by anything up to 6 or 7 problems right now, although a couple aren't it because it's been fine until now so don't assume it is the valve you mentioned just yet. If someone advertises as G3 then they should know what to look for. If he/she can't fix it then by all means come back.