Tundish Overflow

[dazmanplumber]

Hi everyone my nextdoor neighbour has asked me to ask on this forum a question for her.

What it is is she has a system boiler and it has a tundish by the hot water cylinder. But now and then i dont know if its when the heating or hot water kicks in but the water gushers through this tundish. Not a trickle like mine does but lots of water and it is actually killing the plants outside where the pipe leaves the building as it is very hot.

Does anyone know if this is normal or a serious problem?
Is the tundish just to help let the expanded water leave the building. Ie does what an expansion pipe would do in a vented system.

Many thanks Darren

 

[lagunaglen]

It sounds as if she has an unvented hot water cylinder,which has a fault hence water exiting the tundish.Even yours should not have a trickle.
The problem could be several things so it needs to be looked at by someone competent with Unvented systems as this is a requirement by law.
I would advise switching the boiler off until it is sorted .

 

[bengasman]

These things are supposed to be serviced annually, like the boiler. Would I be far off guessing that it has been more than a year?

 

[dazmanplumber]

I moved in to my house 2 years ago and the lady next door about 2 weeks after me but they are brand new houses. And yes neither of us have had either boiler or cylinder serviced but i thought it might be a bit like a brand new car does not need servicing for a couple of years. But i will ask next door if i book a plumber to service both are houses he might give discount.
Cheers

 

[bengasman]

Good idea to do both houses at the same time, certainly won't hurt the price. Make sure that the chap that does the job is qualified for boilers as well as unvented cylinders, as they are 2 totally different things.
Bit of topic, but I really wouldn't wait a couple of years to have my car serviced either, irrespective of whether it is brand new or 10 years old.

 

[dazmanplumber]

understood will do that.
So i take it then that if water is dripping into the tundish it is a sign that there is something wrong. Its only cos if i turn the pressure relief valve slightly then water drips out so i just presumed that all that was happening was the water was getting hot expanding then dripping out. But like i said next doors is coming out by her plants like a tap is on.
(oh dear)

 

[bengasman]

The pressure relief valve is a safety device, and under normal working conditions it should not be activated.
I don't do unvented, but some of the guys on here are very able to give you chapter and verse on them.