Tundish leaking water.... advice sought

[Jonna]

Hi All,

First post...

I bought a new Bellway house last year and have had a few probs with it since moving in. After around 4 months (December 2010) I noticed damp in the kitchen ceiling below the cylinder. On inspection the water (cold) appeared to be leaking from the tundish, which tuned out to be the result of a frozen blow-off waste pipe outside. The plumber stopped the leak (no idea what work was carried out), and added lagging and a cover to the external pipe.

On Sunday, I noticed water dripping from the ceiling again in the kitchen... same issue as before, water appears to have been leaking from the tundish. No blockage in the external blow-off drain however, in fact there are signs that a large amount of water has been draining outside. Plumber came, but suggested he'd need to take the ceiling out in the kitchen to locate a fault in the blow-off drain - he advised he'd have to come back later.

Came in tonight and noticed more water in the ceiling and more outside. There's also evidence that water has been overflowing from the tundish...

I'm waiting for a call back from Bellway regarding the plumber, but was hoping you guys could clarify...

1. Why the tundish? This thing doesn't appear to be capable of managing a heavy flow of water, and when a heavy flow (i suspect) does ensue, water pours out, down the outside of the pipe onto my kitchen ceiling.

2. Any ideas what would cause a constant dripping of cold water through the tundish? (faulty blow-off valve perhaps, or too high pressure in the system?)

Thanks. :cry_smile:

 

[Jonna]

Thanks for your input all...

Has anyone seen a 15 into 28 tundish? might stick one in myself or request that the plumber do this when he turns up. A larger diameter might cope with the flow better?

Was also thinking of sticking a hosepipe down the D2 pipework to see how well it handles the flow... if it overspills, I'd at least have justification in requesting the plumber to check it out.

Where exactly is the diaphragm that's been mentioned? I'd imagine the first thing for the plumber to look at would be the prv on the pressure vessel. Then again the water that's dripping through the tundish seems to be cold, and I'd assume it would be hot if coming from the heating prv? - could just be coolling by the time it reaches the tuncdish though.

Thanks again.

 

[solar tido]

If you have a seperate expansion vessel the diaphragm is in that, if it is a cylinder with an expansion bubble it is in the top of the cylinder

 

[Gray0689]

The red expansion vessel for heating White one for domestic the diaphragm is inside these unless your cylinder has a air gap then there will jot be a White expansion vessel

 

[Dannypipe]

Thanks for your input all...

Has anyone seen a 15 into 28 tundish? might stick one in myself or request that the plumber do this when he turns up. A larger diameter might cope with the flow better?

Was also thinking of sticking a hosepipe down the D2 pipework to see how well it handles the flow... if it overspills, I'd at least have justification in requesting the plumber to check it out.

Where exactly is the diaphragm that's been mentioned? I'd imagine the first thing for the plumber to look at would be the prv on the pressure vessel. Then again the water that's dripping through the tundish seems to be cold, and I'd assume it would be hot if coming from the heating prv? - could just be coolling by the time it reaches the tuncdish though.

Thanks again.

You can get 22 to 28 mm tundish. All you would need is a 22/15 reducer and job done on that point. I've not read the rest of the thread so excuse me if I missed the point.

 

[GrahamM]

One use of the tundish is to provide an air gap to allow the discharge to drain freely and safely away without any vacuum resisting the flow.. I was concerned when you mentioned this splashing water. The tundish is an open vessel and to a degree there will be some spillage, but if this spillage is excessive it is incorrectly fitted as far as I am concerned and I have marked a number of installations as 'At risk' because of this in past. At the end of the day this must be capable of handling a stream of high pressure ￾￾water at temperatures as high as 95°C safely. If this is splashing excessively-it is not safe. I check a few of these every week and the vast majority operate safely as they have been designed/fitted so.
Looking at your pics there is what appears to be a horizontal run of 15mm pipe from the temp/pressure relief valve. This is not ideal to start with. This should ideally terminate vertically and run directly into the tundish and should fall continuously to a safe termination in the correctly sized D2 pipework.

I am not aware if you can get a 15 to 28mm tundish but what you may do is fit a 22 to 28mm one and tee into the top in 22mm. This may or may not help the issue. As I mentioned, only someone competent in fitting/inspecting unvented cylinders can advise.

 

[Jasonh]

Ptfe wrapped round the tundish? Looks like possibly leaking from where the two halfs of the tundish join, pipework could be under tension causing tundish to split, so when valve letting by leaking from this point, seen it before, making a mess of the ceiling below. Still need to suss why a valve is dripping but also replace tundish i would think.

 

[glasgow guy]

could be a number of things like mixer taps or shower but you should get it sorted quickly

 

[GerrythePlumber]

I've read all these posts and noticed a couple of things. As you are in Glasgow the pressure will probably be very high in the water main in the area, possibly up to 14bar. The water board will have a PRV fitted to reduce this.
1. Is your incoming main excessively high? If so, then contact them.
2. The tundish looks as if it's been repaired.
3. The tundish should be no more than 500mm from any temp or pressure relief valves. The D1 from your heating looks to be more than a meter.
4. Three D1's should connect to tundish in 22mm.
5. You mentioned gurgling when you blew down D2. This means that water is lying in D2. There should be no water in D2 as there must be a continuous fall. Water lying in D2 could cause an airlock in the pipe and allow it to back up through the tundish.

 

[GerrythePlumber]

Just thought of something. Your house is 1 year old! I take it you have a HE System Boiler. Why do you have an expansion vessel on your heating? Can you show a pic of the whole cylinder cupboard and pipework?

 

[GQuigley67]

isn't the OP in Newcastle ???