Tundish on unvented cylinder

[Mgrant]

Hey is it usual for a tun-dish to splash alot of water out when testing the discharge of the pressure or temperature relief on full? There's no problem with the discharge pipe over 300mm before first bend after tun-dish and less than 9 meters in 22mm.

 

[townfanjon]

yep James they generally do splash, some a lot, some a little.

 

[AWheating]

yes it always happens and they are not really a very good design/fit for purpose

 

[Meady]

I always find this happens, my one at home only goes about 5 metres in 22mm and is 500mm from the tundish to the first bend. You have to let the pressure go slowly or the water goes everywhere.

 

[AWheating]

I always find this happens, my one at home only goes about 5 metres in 22mm and is 500mm from the tundish to the first bend. You have to let the pressure go slowly or the water goes everywhere.

What a plumber who bothers to check/service his own plumbing?? what is this world coming to???

 

[Mgrant]

Ok if the pressure or temperature relief did blow of is it likely to be at full bore or not? The splashing could cause some damage especially with the position of the cylinder in the loft.

 

[SimonG]

Ok if the pressure or temperature relief did blow of is it likely to be at full bore or not? The splashing could cause some damage especially with the position of the cylinder in the loft.

It will be running quicker in a failure mode than just a simple manual discharge.

 

[Mgrant]

So if the cylinder did discharge it would cause quite abit of damage due to the tun dish splashing. Would it be worth getting the manufacturers out to look at it?

 

[josh]

As said nearly all of them do it, so what would they say?
500mm of 28mm straight from tundish does take it away quick enough though but still get the odd drip sneak out.

 

[Mgrant]

As said nearly all of them do it, so what would they say?
500mm of 28mm straight from tundish does take it away quick enough though but still get the odd drip sneak out.
It a 22mm connection on the tundish outlet. And 22mm pipe takes it away 0.7 meters to first bend under tundish and less than 9 meters of 22mm pipe. Its splashing out of the tundish not backing up.

 

[Mgrant]

Its alot more than an odd drip that's sneaking out

 

[josh]

I wouldn't worry about it, i'm sure someone on here has but i'v never heard or seen a PRV/expansion relief let go full bore. only ever trickle.
You can go on and worry forever about everything and anything if you wanted.

 

[Mgrant]

I wouldn't worry about it, i'm sure someone on here has but i'v never heard or seen a PRV/expansion relief let go full bore. only ever trickle.
You can go on and worry forever about everything and anything if you wanted.

Thanks so they don't usually discharge on full bore? Its only on full bore when it is splashing over.

 

[townfanjon]

The only thing I try do to help is to try make the first bend as far away from the tundish as poss, defo use a pulled bend , and try keep the rest of D2 on a 'fall'.
If it's just about horizontal and you use an elbow, it won't help.

 

[josh]

I'm sure some have but i have never heard of it/come across it.
You have followed the regs and MI's so what more can you do.

 

[stratplus]

Hey is it usual for a tun-dish to splash alot of water out when testing the discharge of the pressure or temperature relief on full? There's no problem with the discharge pipe over 300mm before first bend after tun-dish and less than 9 meters in 22mm.

Especially the angled ones.

 

[stratplus]

Fitted loads of unvented in lofts, 1 1/4" pushfit from hepvo 1 bend into soil, test prv and still p's out all over top of tundish.
The angled ones 90 deg were ridiculous.

 

[GrahamM]

Thanks so they don't usually discharge on full bore? Its only on full bore when it is splashing over.

Most will splash quite a bit when you test it.
Unlikely to blow off at full bore in normal operation. Pressure/temperature would have to be building up dramaticly for the TPRV to release at full bore splashing out.

 

[Ermintrude]

Ok if the pressure or temperature relief did blow of is it likely to be at full bore or not? The splashing could cause some damage especially with the position of the cylinder in the loft.

Both won't ever go at same time it's a tiered values setup tprv last resort.

 

[Mgrant]

Fitted loads of unvented in lofts, 1 1/4" pushfit from hepvo 1 bend into soil, test prv and still p's out all over top of tundish.
The angled ones 90 deg were ridiculous.

Thought they couldn't go in to soil stacks any more?

 

[Mgrant]

It is an angled one that comes off the top of the oso cylinder

 

[Meady]

What a plumber who bothers to check/service his own plumbing?? what is this world coming to???

Blimey mate your having a laugh ain't you, I've lived in my house nearly 2 years and still haven't gotten around to servicing the boiler

 

[Killy Bing]

Blimey mate your having a laugh ain't you, I've lived in my house nearly 2 years and still haven't gotten around to servicing the boiler

both unventeds in this house get a service a year, the boiler twice

 

[stratplus]

Thought they couldn't go in to soil stacks any more?

Usually as a last resort but if stack and cylinder are in the loft next to each other it makes sense.

 

[stratplus]

Usually as a last resort but if stack and cylinder are in the loft next to each other it makes sense.

Saying that, shouldnt the discharge be visible either at the tundish or termination point! If its in loft it won't get seem. Hmmmmm.....

 

[chris watkins]

Remember when you guys did the Part G ticket & the training centre showed you the test rig with the Pressure relief going off & then the Temperature relief did you not see or was it not explained what was happening & why?
You did do your training didn't you ?

As for loft installs with wastes discharging into soils, do we really think this is such a good idea ??
Just stop & think for a sec.
1, How often is anybody going to be in the loft to spot any discharge via the tun dish &
2, Going to the soil / waste it will never be seen at this end either.

Chances are it will keep on running wasting water or worst case it will scale up & will not work when it is actually needed.

There is a statement made that Hep Vo's & discharge to stacks should only be used when there is no other way of discharging it safely I do not believe this to be the case in most lofts.

 

[grahamkeen1]

Hi,
Given that Tundishes do splash a little, is there such a thing as a cover for them or a hood, that would at least ensure that the water splash only went downwards ? Would like it to splash onto the immersion heater switches.
Thanks, Graham.

 

[chris watkins]

Have you got your Part G ticket graham ?
You must always maintain an AA air gap on tun dishes.

 

[snoopy8888]

At my age, i tend to drip more than spash. :devil2:

 

[Dotty]

Please register with us and start a new thread to receive an answer to your question.