Pressurised heating system constantly dripping

Matt_Hirst

Matt_Hirst

Matt_Hirst

Associate
Joined
27 Jan 2005
Posts
1,409
Location
S. Yorks
A few years ago we had a pressurised system installed, we'd had new bathrooms and shower pressures were poor.

Anyway all was well until we tried getting hold of the guy who fitted the system to have it serviced, no response.

Anyway for the past month we've noticed the outlet pipe to the outside drain is dripping almost constantly.

We tried ideal website to find another guy to come service the system but he came out and if honest we were not convinced he knew what he was doing or indeed wanted to actually help.

So question is, what could be wrong with the system?

Matt
 
Copper pipe or plastic?
What is the system pressure when cold?

If it's plastic pipe it'll be the condense drain, that should terminate in a drain or waste pipe.

If its copper pipe then the system pressure is likely around 3 bar.
If you're not topping the pressure up regularly then it's either the fill loop open/passing or the plate heat exchanger cracked between the cold mains and heating.

If you are topping it up then it's likely the expansion vessel, take note of the pressure when cold and see what it rises to once the heating is turned on.
This very often causes the pressure relief valve to start passing as well so I normally like to change them together.
 
Hi,

Its copper pipe. Never done anything with it myself but had a plumber fit new radiators about six months ago and he did whatever needed to get them working.

Will try post some pics up of it tommorow.

Matt
 
Hopefully pictures here:

boiler3.jpg

boiler2.jpg

boiler1.jpg


Matt
 
Last edited:
This is odd. I saw this post the other day but couldn't help. Then, weirdly enough, my tundish for my hot water cylinder started having water run past it after I showered. I don't know if it's been doing this since I have lived here but thought I heard a weird noise coming from my recently installed AC unit on the wall opposite which led me to investigate the cupboard and then spotted the cause of the noise (running/dripping water).

I asked someone I know (plumber) to investigate but he told me to try a few things first over the phone. I turned the hot water cylinders PRV which opened and closed and reseated ok as it should (water briefly blasted out through the tundish). Then he suggested to press the schrader valve (like a bicycle/car tyre valve) on top of the pressure vessel (had to unscrew a large black plastic cap first) to see if any air came out. When I pressed the schrader valve, nothing happened. He told me to isolate the mains supply to the hot water cylinder and open up a hot and cold tap. Then pump up the pressure vessel to 3.5bar. This took bloody ages (I can pump up two bikes to 6 bar in minutes normally) and whilst I was doing it I could hear the bladder inside the vessel opening up, and water coming out my taps as if it was pushing water out the bladder.

I am hoping I don't need a new pressure vessel as I know they are about £100 or so I think

Hopefully you can get your pictures to work so we know exactly what you are referring to :)
 
Can't work out why pics won't work, I get option to open then in another tab when clicking them just can't get it to work as a direct link.

Matt
 
I had the exact same thing (it sounds like) happening in dramatic fashion one day when we got back from holiday and the geofencing system recognised we were on our way home, kicking in the hot water from what was a cold tank:


The problem was that the hot water expansion vessel had lost pressure and needed to be recharged.

The plumber did what fobose said above, i.e. isolate then recharge.

It was then fine for a couple of years and has just started doing it again.

Worcester Bosch did come round and replace the pressure relief valve and the pressure reducing valve just in case, and said if it happens again will replace the expansion vessel under warranty.

They also replaced the tundish because it was, as is obvious from the video, insufficiently sized. I'm just glad the system is in our garage and not in a cupboard in the top floor of our house!

We had just had our bathroom replaced at the time... unlikely to be a coincidence because your average bathroom fitter doesn't understand unvented systems.

The dhw cylinder needs the expansion vessel to take up the extra pressure when the water is hot and if it can't do that, pressure exceeds the maximum allowed and the tundish lets by to relieve the pressure.
 
So far mine is working correctly. I keep forgetting to check the pressure of the expansion vessel before the hot water comes on. Must remember to do that today when I get back from work.

That is a lot of water letting by in that video! Mine was no where near that amount, a constant small stream of water only. It is on the top floor of my house so I would be a bit worried if mine was spilling out everywhere like that!
 
fobose said:
That is a lot of water letting by in that video! Mine was no where near that amount, a constant small stream of water only.
Click to expand...
Constant small stream is what mine's doing now. I'm going to try and recharge it today.

I think the volume of water there was exceptional because the (powerful) boiler was going balls out trying to quickly reheat 300L of cold water.
 
I assume the OP means a boiler not a cylinder, as he's said it's heating and he's looked to Ideal for help.

Cylinders have a constant supply of cold water to leak out, boilers are sealed so an expansion vessel fault wouldn't cause a continuous leak.

Probably need clarification from the OP as to what exactly is leaking.
 
Danm54 said:
I assume the OP means a boiler not a cylinder, as he's said it's heating and he's looked to Ideal for help.

Cylinders have a constant supply of cold water to leak out, boilers are sealed so an expansion vessel fault wouldn't cause a continuous leak.

Probably need clarification from the OP as to what exactly is leaking.
Click to expand...

Not so sure. The OP's first sentence strongly hints at a cylinder fault imo: 'A few years ago we had a pressurised system installed, we'd had new bathrooms and shower pressures were poor.'

...and Ideal do make unvented cylinders as well as boilers.

But yes if the OP could pull his picture posting finger out that would help.
 
Participant said:
Not so sure. The OP's first sentence strongly hints at a cylinder fault imo: 'A few years ago we had a pressurised system installed, we'd had new bathrooms and shower pressures were poor.'

...and Ideal do make unvented cylinders as well as boilers.

But yes if the OP could pull his picture posting finger out that would help.
Click to expand...

With heating in the title I assumed he had a combi, reading it again it does sound like a cylinder is more likely though.

Forgot Ideal made cylinders as well, only really see their boilers.
 
i had the constant dripping pipe afew times actually ,so when the system ran i watched the gauge and it quite obviously over pressurised ,the pressure release valve did its job and off loaded the pressure through the pipe.
once the reason was the pipe that joins the expansion vessel to the system ,full of crud ,i thought it might be the diaphragm in the expansion vessel but swapped that anyway as i had an old donor boiler .then the actual pressure relief valve was faulty (pressure fine but still dripping) ,probebly full of grime from my system and saftey failed in the open position .
 
So which bit is leaking?

The tundish in the second pic looks like it's had water going through it for a while. That's from the cylinder so if it's that then it's likely the expansion vessel (white one in the second pic).
You can check the pre charge by turning the hot water off (yellow lever valve) and opening a tap, then checking the pressure with a normal pump.
The precharge info will be on a data badge on the vessel.

The boiler is a little low on pressure so I wouldn't think that's continuously leaking unless you're topping the pressure up regularly. Needs a top up to 1 bar when cold though.
 
You must log in or register to reply here.
Back
Top Bottom