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Any plumbers? Help! Water pressure dropping in central heating system!

24
Found 8th Dec 2013
A few months ago I got a local plumber to install a new boiler into my house. First things first, I don't doubt the integrity of the plumber, he's done well and tried to rectify the following fault but before I part with any more money I want to make sure he's doing the right thing.

The boiler he installed is a Worcester Greenstar 30CDI Classic System. We have approximately 22 radiators around the house. The previous boiler had packed up completely and hence why the new boiler was installed. Also to add that the previous boiler was a huge floor standing boiler and this boiler is wall mounted and smaller in size. The problem is as follows;

When we switch on the heating (or water), initially everything was working ok (for the first few days) until one day I switched it on and realised it wouldn't start up at all. Looking at the pressure dial on the boiler I realised it was on ZERO! I contacted the plumber and he told me to go up into the attic and there were two valves on a pipe which when turned would top up the water tank (which is a Megaflo). By the valves is another pressure gauge which I would monitor till it reaches 2 bars and then switch off the valve. This would it appears top up the system and allow the boiler to start.

The problem is that I have to do this everytime I want to use the heating! Fortunately I have an attic conversation and accessing the water system isn't an issue, but it does mean that either my wife or I have to be home to switch on the heating for my mother who is elderly.

When using the heating the pressure initially would have dropped to 1 bar till I would switch it off, but now after 3 hours use it reduces to ZERO and then stops working till I top it up again.

The plumber has been baffled by this himself and has helped to try and resolve the issue. Initially he came and put some liquid into the pipes to close and seal any potential leaks. I think this worked a little initially but now hasn't helped at all from what I can see. A few weeks ago he spent a whole day lifting floor boards where possible or drilling holes into the floorboards to search for any leaks underneath that we can't see. What he is saying is that there is a leak somewhere which is causing the water pressure to drop.

He has 2 suggestions to move forward. Firstly he wants to come back and use an infra-red imaging camera to try and find any potential leaks under kitchen tiles etc which we can't find. Secondly he is suggesting that we replace the Megaflo (at my expense) as he says that there may possibly be a crack inside which is where the cause is. The Megaflo is approx 10 years old, has worked absolutely fine till now and I don't think this is the issue. I don't know if this has any connection but when the water in the tank is hot it stays hot for 5-6 hours. I would have thought that if there was a leak it would cool down fairly quickly.

Any suggestions to help resolve this matter would be greatly appreciated. I don't think I can continue through winter with these issues.
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If you're having to do this even once a month then its a problem. This most certainly sounds like a leak. What happens is, if water (or air) is getting out of the pressurised system, the pressure drops. This would happen when, for instance, you bleed air out of your radiators. But if it happens on its own then the water must be going somewhere else. So it certainly sounds like a leak.

Sorry to be the bearer of bad news.
I 2nd the about comment. There must be a leak somewhere. Seeing as their wasnt an issue with dropping pressure with the previous boiler ? It might be as simple as the pressure release valve having a slow leak.
Original Poster
mickrick

If you're having to do this even once a month then its a problem. This … If you're having to do this even once a month then its a problem. This most certainly sounds like a leak. What happens is, if water (or air) is getting out of the pressurised system, the pressure drops. This would happen when, for instance, you bleed air out of your radiators. But if it happens on its own then the water must be going somewhere else. So it certainly sounds like a leak.Sorry to be the bearer of bad news.



Many thanks.. this is what I'm afraid of. The problem is that finding that leak seems to mean taking the house apart.
Wow! Sorry for the spelling mistakes
Original Poster
bubblegum2910

Try this forum http://www.diynot.com/forums/viewforum.php?f=7



Thanks. Will post in that forum hoping for a reply.
I firstky would look at the overflow pipe located on the boiler when you have your heating on it most likely drips (outside) reaason for this is you have 22rads water expands and I pressume the expansion vessel in the boiler cant take the expansion therefore pressure guage would go up to 3bar and pressure relife valve discharging outside cheapest solution buy an external expansion and fixing and fitting approx 50 material that should resolve any issues.
have you checked the outlet pipe from the boiler? by this i mean the pipe which runs to the outside of the house, which releases water if the pressure gets too high. look to see if it is dripping, sometimes the pressure release valve can become un seated, and it will leak water to the outlet pipe.

I had a 35cdi and this was the problem, along with a blown expansion vessel in the boiler, but as yours is new I doubt the EV has gone, and the plumber would / should have checked this
ascotplumbing

I firstky would look at the overflow pipe located on the boiler when you … I firstky would look at the overflow pipe located on the boiler when you have your heating on it most likely drips (outside) reaason for this is you have 22rads water expands and I pressume the expansion vessel in the boiler cant take the expansion therefore pressure guage would go up to 3bar and pressure relife valve discharging outside cheapest solution buy an external expansion and fixing and fitting approx 50 material that should resolve any issues.



Beat me to it lol
The pressure drop means water is exiting somewhere so this obviously needs addressing. A couple of suggestions. If there are no water stains on the ceilings, the leak may be at basement level. Do you have a cellar or are the floors concrete?
When you fill the system, are you having to bleed the radiators? If yes, the leak is in the system. If no, the fault may lie in the boiler. The boiler will have a pressure overflow pipe. Check to see if this is purging the system. This could be as a result of a faulty pressure relief valve.

If you haven't already, register for the 5 year guarantee worcester-bosch.co.uk/hom…ion
Were having the same problem, doh!!
To check if the megaflo coil is a fault is isolate water to the megaflo and empty it (through the taps) then run the heating system and see if it starts to fill the megaflo it will take a while as i expect the megaflo is quite big but worth a try if the overflow issues as said above seem ok.
Original Poster
sparxuk

have you checked the outlet pipe from the boiler? by this i mean the pipe … have you checked the outlet pipe from the boiler? by this i mean the pipe which runs to the outside of the house, which releases water if the pressure gets too high. look to see if it is dripping, sometimes the pressure release valve can become un seated, and it will leak water to the outlet pipe.I had a 35cdi and this was the problem, along with a blown expansion vessel in the boiler, but as yours is new I doubt the EV has gone, and the plumber would / should have checked this



I need to check with the plumber but I'm sure he's checked this as he mentioned the EV was the first thing he'd check. Like I mentioned before, I don't doubt his honesty. He did the job really well and didn't ask for any money until about 4-5 days later. At that point I wasn't aware we had a problem this severe. He's also been back and spent an entire day trying to get to bottom of this. Thanks for your suggestion.
Original Poster
darksideby182

To check if the megaflo coil is a fault is isolate water to the megaflo … To check if the megaflo coil is a fault is isolate water to the megaflo and empty it (through the taps) then run the heating system and see if it starts to fill the megaflo it will take a while as i expect the megaflo is quite big but worth a try if the overflow issues as said above seem ok.



I don't think I'm going to be able to personally figure out how to do this. The water tank has a lot of pipes and valves around it. I think I'm going to suggest to the plumber if he's done this already to isolate the problem. Personally I think the issue is in the system.
Original Poster
lalo2684

Were having the same problem, doh!!



I'll let you know if I can find a solution!
Original Poster
The Therapist

The pressure drop means water is exiting somewhere so this obviously … The pressure drop means water is exiting somewhere so this obviously needs addressing. A couple of suggestions. If there are no water stains on the ceilings, the leak may be at basement level. Do you have a cellar or are the floors concrete?When you fill the system, are you having to bleed the radiators? If yes, the leak is in the system. If no, the fault may lie in the boiler. The boiler will have a pressure overflow pipe. Check to see if this is purging the system. This could be as a result of a faulty pressure relief valve.The plumber and I looked for any visible leaks. there is nothing upstairs and we don't have a basement (might have made things easier if we did!) Downstairs we have floorboards and tiled floor (porch, bathroom and kitchen). I'm hoping the leak isn't under any of this as it would mean taking up the flooring and ruining what has been down for 10 years plus. I mentioned before that he spent a a day drilling holes in the floorboards in search of any leaks below. He's mentioned about coming back with a device to look for any leaks using variant temperatures. It won't work over carpets so that will be pulled up, but it should work over tiles (so he has said)If you haven't already, register for the 5 year guarantee http://www.worcester-bosch.co.uk/homeowner/events-promos/5-year-guarantee-promotion

Original Poster
ascotplumbing

I firstky would look at the overflow pipe located on the boiler when you … I firstky would look at the overflow pipe located on the boiler when you have your heating on it most likely drips (outside) reaason for this is you have 22rads water expands and I pressume the expansion vessel in the boiler cant take the expansion therefore pressure guage would go up to 3bar and pressure relife valve discharging outside cheapest solution buy an external expansion and fixing and fitting approx 50 material that should resolve any issues.



As far as I'm aware, the plumber has checked the overflow pipe. He seemed to know quite well what he's doing. I got several quotes for the job and the other two appeared like cowboys in comparison (price and when I asked what they were going to do). The pressure valve has never gone up to 3 bar. From 2 bar where it starts when I fill up the system and switch on the boiler it slowly goes down to 1 bar, and it used to stay there till i switched it off but now it drops down till the boiler stops. Can you elaborate more on the externam expansion you mentioned?
It sounds like youve got an experienced plumber there so its not going to be anything obvious or he would have already found it.Blow off pipe would have been the first thing he checked.Its unlikly to be the megaflow since that was ok before.It sounds like a slow leak on a pipe thats been recently fitted and cant be seen anymore,probably under the floor.Look for any kind of damp patches.
Original Poster
redlight

It sounds like youve got an experienced plumber there so its not going to … It sounds like youve got an experienced plumber there so its not going to be anything obvious or he would have already found it.Blow off pipe would have been the first thing he checked.Its unlikly to be the megaflow since that was ok before.It sounds like a slow leak on a pipe thats been recently fitted and cant be seen anymore,probably under the floor.Look for any kind of damp patches.



There were 3 rads he fitted as part of the boiler installation (replaced old rads for new) and that was the first thing he checked. We've moved furniture around to look for any sign of damp patches and still nothing. Its baffled him and in a way I think he feel embarrassed that this has happened. He in touch with me quite a lot to come back and sort something out and the main reason for this post today was to try and isolate the megaflo as the area of concern from the rest of the heating system which I this is where the problem lies.

Thanks for your input. I'm going to call him tomorrow morning and try to get him back in this week.
It could be the boiler itself is allowing the water to by-pass in the sealed system so Id suggest contacting the boiler manufacturer as it should still be within warrenty.
Suggest to the Plumber that he do a pressure test of the system with the boiler removed/isolated from the circuit.


Edited by: "arachnoid" 8th Dec 2013
Original Poster
arachnoid

It could be the boiler itself is allowing the water to by-pass in the … It could be the boiler itself is allowing the water to by-pass in the sealed system so Id suggest contacting the boiler manufacturer as it should still be within warrenty.

It does have a long warranty as it was only installed a few months ago. I'll get the plumber back in this week so fingers crossed the problem is found.
Hi Madferrit
I'm wondering if you found a leak? How was it resolved in the end?
We're having a very similar problem and not many ideas left!
Thanks in advance
Muls99
Get the engineer to ring Worcester Bosch and speak to their team, they give very helpful advise over the phone - who knows maybe a faulty part in the boiler???? I had the 28CDI for a smaller house and its been brilliant since day 1. The one thing I have found out in the past when adding new piping any "disturbances" on the pipework to put the new piping on often causes the old joints to come lose and leaks to happen. Don't just look at the new stuff.

Can you put newspaper or tissue under anywhere there is piping/joints that you suspect might leak (around the boiler?). If there is even a tiny leak the paper will get wet and you can look more thoroughly in that area.
Original Poster
muls99

Hi MadferritI'm wondering if you found a leak? How was it resolved in the … Hi MadferritI'm wondering if you found a leak? How was it resolved in the end?We're having a very similar problem and not many ideas left!Thanks in advanceMuls99



The problem was found under some tiles in a bathroom downstairs. We only noticed when we saw some water sitting on the tiles when it wasn't near the sink or shower in the bathroom. Removing the tile on the floor exposed the leaking pipe.

Good luck with your problem.
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