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Discuss Dripping Tundish on a Tribune HE hot water tank in the Looking for a Plumber? Post Jobs Here area at

Tundish dripping, not sure if TRV or another pressure relief valve, the mini white tank not being upto pressure or something else.
Suppose job will be work out problem of dripping, and also help identify why diverter valve won't activate when hot water is needed to be tested. I have to hit the motor to get it to kick in but recently replaced thermostat with a new one.

I live in Launceston Cornwall



Gas Engineer
Advent Win
You could have put these on one post .
Tundish dripping , you need a G3 registered plumber to look at it , theres nothing really you can do .


There are three possible causes for the dripping T&P valve. The simplest is that the expansion vessel has lost its air charge and just needs pumping back up to correct pressure. It is also possible the diaphragm within has failed causing the same symptoms as no air charge. This is the most common cause.

The T&P valve itself may have failed and might need replacing. It happens but usually after a stat failure (or during testing at service) and subsequent discharge and they often fail to re-seat properly after the temperature returns to normal. This might have happened when your old stat went faulty.

Thirdly it could be that the pressure reducing cartridge in the combination valve (aka Group Inlet) has failed and the cylinder got up to incoming mains pressure but that is the least likely scenario by far.

It's a G3 registered engineer's job I'm afraid. I believe I am OK to tell you what I think might be wrong with it but you cannot work on this cylinder yourself sorry to say.

If I have broken the rules by giving out this information, Mods please delete and accept my apologies. It's a bit of a grey area for me after we went international!


Staff member
S. Mod
Gas Engineer
Definitely a g3 engys job / realm

Harvest Fields

Gas Engineer
Advent Win
As there is a drip into the tundish. I would personally get a G3 registered engineer in to take a look. When was the unvented cylinder last serviced? I would also get him to change the actuator head at the same time. It will probably save you about £25.00 from doing it yourself.

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