Very high water consumption

[JX350C]

I've now managed to get some further testing done. I've shut off all isolation valves to all the taps, toilets, dishwasher, washing machine etc and I can see that the meter is still increasing without any visible water usage. I then isolated the showers and checked that the fill loop was closed to the UHF. Water was still being used. I then switched the hot water controller to off instead of auto and water was still being used.

So I then isolated the water supply to the laundry room where the cylinder, heating controls and UFH manifolds are. The water usage then stopped immediately. Below is the valve I switched off.

This valve supplies cold water to the showers, UFH fill and the cylinder. I have shut off the showers as they have smaller isolation valves after that main valve. I've confirmed that the fill for the UFH is closed and it is not letting water past at all. However, there is no further isolation valve to the cylinder so I can't seem to isolate that on it's own.

 

[John.g]

Ensure all hot taps off then shut that lever valve again and after a few minutes open any hot water tap, you should get a few litres (from the expansion tank) flowing.

 

[John.g]

Can you have a look at the photo.

 

[ShaunCorbs]

Can you have a look at the photo.

That’s a 3 bar safety valve

 

[JX350C]

Can you have a look at the photo.

That valve has the main cold water feed to it at the top and then two pipes from it. One of those out pipes goes down and connects to the cylinder and the other connects to the pipe with the tundish in it. I'll get a better picture of that for you.

 

[JX350C]

Can you have a look at the photo.

Here are some pictures of that valve and connections closer up. The pipe in the top of it is the main cold water feed which has the large blue isolation valve on it.

And the above image shows how it connects to the cylinder. This pipe by the way is quite hot but I presume that's because it's connected to the cylinder.

 

[John.g]

Yes, (as Shaun pointed out), its the expansion valve probably set to 6bar since the cylinder temperature and pressure relief valve is set to 90C/7bar.
Theres another pipe underneath this expansion valve going off to the right?, where is the expansion vessel connected into the system
Are you absolutely sure that there is no water flowing down through the tundish.

 

[JX350C]

Yes, (as Shaun pointed out), its the expansion valve probably set to 6bar since the cylinder temperature and pressure relief valve is set to 90C/7bar.
Theres another pipe underneath this expansion valve going off to the right?, where is the expansion vessel connected into the system
Are you absolutely sure that there is no water flowing down through the tundish.

That pipe off to the right goes to a large white tank. I've taken some other pictures of the whole install but here is one showing that large white tank. And I do keep checking the tundish and there doesn't appear to be anything dripping through it.

 

[John.g]

Thats fine, its to the expansion vessel.
The cold water to the cylinder shoud not be hot except maybe very close except its flowing back and out through the expansion valve and down through the tundish when the cylinder is heating up and if the expansion vessel has failed but should still only expel a few litres of water each time the cylinder is heating up.

 

[JX350C]

Thats fine, its to the expansion vessel.
The cold water to the cylinder shoud not be hot except maybe very close except its flowing back and out through the expansion valve and down through the tundish when the cylinder is heating up and if the expansion vessel has failed but should still only expel a few litres of water each time the cylinder is heating up.

Ok thanks. That pipe is hot most of the way up until it gets near the T and then it's cooler above and to that white tank.

 

[ShaunCorbs]

If you turn the silver screwdriver valve off does the water meter stop ?

 

[JX350C]

If you turn the silver screwdriver valve off does the water meter stop ?

Sorry, which one do you mean?

 

[ShaunCorbs]

Sorry, which one do you mean?

The one by the white vessel 15mm silver valve on the hot

 

[JX350C]

The one by the white vessel 15mm silver valve on the hot

Ah ok. That one is to the feed for the showers. I'll try it. Thanks

 

[John.g]

Can you just switch off the laundry supply to get the meter to stop turning and then check the meter readings while filling a 10 or 20L bucket to confirm that it's metering correctly.

 

[JX350C]

We went out all day yesterday and took a meter reading in the morning and the meter read an increase of 569 litres since the previous day overnight. We didn't use any showers, baths or washing machine. We put on the dishwasher once in that period and used the toilets.

So yesterday after that meter reading, I switched off the mains water isolation valve in the laundry room. When we got home last night I took another reading and switched that valve back on. Over 8 hours the meter did not change so we did not use any water over that period with that valve shut off.

With that valve turned off, I ran a hot tap and within about 10 seconds the hot water stopped coming out of the tap.

My landlord is still convinced this problem is a faulty meter even though I have explained the problem and what I have found so far through my testing. He is going to send out another plumber but states that because he can't see any water running down the drain or outside the property then the problem must be the meter.

 

[ShaunCorbs]

Ask them to pressure test the hot water side

 

[JX350C]

Ask them to pressure test the hot water side

Will do, thanks for the help.

 

[John.g]

Have another look at post #50.

 

[JX350C]

Have another look at post #50.

Sorry, for some reason I missed your post. I'll take a look at doing that tomorrow. Thanks

 

[PETE 123]

Check if water is comiong out of condense pipe on boiler it this idea applies
as a heat exchanger may be leaking.

 

[JX350C]

The second plumber came over this afternoon and was really helpful and listened to what the problem was. He went over the basics with me that I had already checked and with everything switched off, and not using any water, apart from the stopcock or the laundry room we checked the meter and it was constantly increasing. He could then see the same problem that we have been seeing.

He thoroughly tested everything and checked around and under the house for water leaks. He found no leaks. Whilst pressure testing he found that the water pressure increased slightly when he isolated the water feed to one of our showers. He found that if he turned the temperature control fully off to 0 on the shower with the shower actually off, the water pressure would increase. Together we checked the meter and it stopped turning when the temperature control on the shower was turned fully to 0 and with the shower off. We retested by turning the control above the 0 position and it immediately started increasing the meter reading. So it looks like the constant 3 to 4 litres of water usage per hour is because of this faulty shower control which appears to be using water even when it is off. We can't determine exactly where the water is going because it's not coming out of the shower head or leaking from the mixer or the controls on each end of the mixer.

Whilst he was testing he said that he noticed the mains water pressure was at 4.5 bar with the shower temperature control problem but when he shut off the shower feed the pressure increased and fluctuated between 6 and 6.5 bar. He showed me a pressure gauge that is on the main water feed after stopcock so I can keep an eye on the pressure. I didn't even notice there was one fitted. There is also a PRV fitted between the stopcock and the pressure gauge and he said that was fully open so he thinks we are losing a lot of water at night as the pressure to the house is increasing overnight and the pressure is being relieved from the cylinder by water going down the overflow pipe through the tundish and hence we are not seeing any water loss through the tundish through the day. He said the cylinder is set to 6 bar before it will relieve the pressure so we think the pressure to the house at night is going much higher. So he has altered the PRV so that the pressure is lowered to 3.5 bar and all the taps in the house can be used at the same time with minimal changes to the flow of each tap. One thing I did notice when testing was that there were signs of water staining on the wooden flooring under the tundish pipe. I hadn't noticed before, but that clearly shows water has been running through the tundish at some point.

We have left the shower temperature control set to 0 for now and there has still not been any water usage for a few hours now. We will not use that shower and I am going to keep taking meter readings for the next two or three days to see if there are any spikes of usage when we know we are not using water and also overnight when we were seeing the huge amounts of water loss. That will hopefully confirm if this is fixed or not.

This is the shower controls that are at fault. The right hand control is the one using water even though the shower is off.

 

[John.g]

There is a PRV on the combination set right at the HW cylinder, did he check this, it would/should have been set to 3.0 bar, if this too is fully open then it would be surprising that you didn't observe water flowing down the tundish even during the day.

Possible though that even with the cold mains to the cylinder PRV set to 3.0bar that the cold water at 6bar is getting through the shower mixer and pressurizing the cylinder via the hot shower supply, then down the tundish, time will tell.

 

[PETE 123]

Could it be that the hot on shower is mains and is passing to the cold that is on a tank supply.

 

[JX350C]

There is a PRV on the combination set right at the HW cylinder, did he check this, it would/should have been set to 3.0 bar, if this too is fully open then it would be surprising that you didn't observe water flowing down the tundish even during the day.

Possible though that even with the cold mains to the cylinder PRV set to 3.0bar that the cold water at 6bar is getting through the shower mixer and pressurizing the cylinder via the hot shower supply, then down the tundish, time will tell.

Thanks John. I'm not sure if he tested the PRV on the right of the HW cylinder. I left him for some of his testing but I know he spent a considerable amount of time testing valves, taps, showers etc.

Exactly, time will tell. I'm keeping logs for the next few days to see. During the day I didn't see any water running down through the tundish and I was regularly checking it. I'll keep you all updated.

 

[John.g]

My kingdom for a pressure gauge on the HW cylinder, it would save a lot of hassle and expense for people if it was included as standard on all unvented HW Cylinders.
Your findings are very interesting in that your plumber saw the pressure rising/falling by 1.5 to 2.0 bar to 4.5bar, if, which seems the more likely explanation at the moment, it is flowinng back through the shower & HW cylinder expansion valve then down the tundish then it points to either the E.valve (or the cylinder safety valve) are gone weak and lifting at 4.5bar or the E.valve has been set too low, also if the HW cylinder PRV has been set to 2.8 to 3.0bar then the E.valve could lift each time a big volume of water is reheated, admittedly to only discharge ~ 4 or 5 litres each time. Also loosing say 400L at night through the HW cylinder should mean that the whole cylinder had to be reheated each morning from practically stone cold, did you notice anything strange about the heat up times?

 

[JX350C]

My kingdom for a pressure gauge on the HW cylinder, it would save a lot of hassle and expense for people if it was included as standard on all unvented HW Cylinders.
Your findings are very interesting in that your plumber saw the pressure rising/falling by 1.5 to 2.0 bar to 4.5bar, if, which seems the more likely explanation at the moment, it is flowinng back through the shower & HW cylinder expansion valve then down the tundish then it points to either the E.valve (or the cylinder safety valve) are gone weak and lifting at 4.5bar or the E.valve has been set too low, also if the HW cylinder PRV has been set to 2.8 to 3.0bar then the E.valve could lift each time a big volume of water is reheated, admittedly to only discharge ~ 4 or 5 litres each time. Also loosing say 400L at night through the HW cylinder should mean that the whole cylinder had to be reheated each morning from practically stone cold, did you notice anything strange about the heat up times?

No I hadn't noticed anything about the heat up times. This is the first time we have had this system and the first we knew about a problem was when the water company commented that we are using very large amounts of water.

 

[EvilDrPorkChop]

Well really all the showers etc. mixer taps should of been taken off the Balance cold on the Combination Valve on the cylinder to prevent this. The easiest way to sort this would be either fit a PRV on the incoming main to 3 bar, or fit a Non return valve to the Hot Outlet on the cylinder.

 

[Chuck]

No I hadn't noticed anything about the heat up times. This is the first time we have had this system and the first we knew about a problem was when the water company commented that we are using very large amounts of water.

There's one thing worse than throwing large amounts of water down the drain and that's... throwing large amounts of hot water down the drain! I suggest you read your meter(s) now so you can compare consumption of gas before and after fixing the problem.

Now you've found a decent plumber, make sure he gives the system a thorough checking-over. I'd try to get a written note of his name, company, and findings so if you want to reclaim the cost of the wasted water and/or gas from the landlord you have the evidence needed to do so.

 

[John.g]

Well really all the showers etc. mixer taps should of been taken off the Balance cold on the Combination Valve on the cylinder to prevent this. The easiest way to sort this would be either fit a PRV on the incoming main to 3 bar, or fit a Non return valve to the Hot Outlet on the cylinder.

Apparently there is a PRV installed on the mains after the stopcock with a PG after it, the plumber found the PRV full open with a apparent mains pressure of 6.0/6.5bar but its a bit strange that this faulty shower was causing the pressure to fall to 4.5bar with it fully open, he has now reduced the PRV pressure to 3.5bar, if this pressure falls excessively with water usage then possibe PRV fault or stopcock or mains restriction that was the reason for the PRV wide opening in the first place and the installation of a pressure gauge?.

 

[John.g]

No I hadn't noticed anything about the heat up times. This is the first time we have had this system and the first we knew about a problem was when the water company commented that we are using very large amounts of water.

Is the water consumption normal now?

 

[JX350C]

Apologies for the radio silence for a while. I've been busy at work and had to work all weekend.

I've been busy taking meter readings most days and especially keeping an eye on overnight readings when we were losing the largest volumes of water. I wanted to ensure that the readings actually reflect our usage so I have been logging each use and then comparing them to the meter reading usage. So far the usage matches the meter readings so this does look like this problem is now fixed. I am continuing to take readings just to ensure they are all good. If all is now good the landlord said he will get the shower fixed as well. He has at least now listened to the evidence and the plumbers findings so has agreed that the problem is not the meter at fault.

Thanks for all the help with getting to the bottom of this. It was very frustrating trying to prove the usage was not from our use but the last plumber was great and saw for himself the constant water usage. It was such a relief when he found the cause of the problems.

Question now is, who should pay me back for all the water that was used that was not our fault.

 

[Chuck]

Question now is, who should pay me back for all the water that was used that was not our fault.

Consult your household insurance, but I'm pretty sure my policy wouldn't cover your scenario. I think that the landlord is the only person you have a claim against. (They, in turn, might be able to pursue the builder of the house.) Seek advice from a solicitor or Citizen's advice before making a claim.

Your landlord will probably assert that they are only responsible for the losses that occurred after you notified them of the problem, which is a position I have some sympathy for but which may or may not be how the law would see it.

It may be worth seeing if the water supplier will give you a rebate. I think this would be discretionary on their part but given the efforts you had to go to identify and fix the leak they might play ball.

Citizens Advice is a charitable organisation. If you consult them and can afford to make a donation, please do so.

 

[Enthalpy]

I would ask the water company to consider a lost water allowance

You could thank the water company for bringing the high water usage to your attention. Explain what has been done to resolve the problem. It might help to inform the water company that you are a tenant.

Good luck.

 

[John.g]

This was a new build so possibly not installed correctly as the cold water supply to the HW cylinder was/is not from the balanced cold connection on the combination valve set, and the HW expansion valve may not have been set correctly to 6.0 bar or it was reduced to 3.5/4.0 bar, it certainly looks as if it wasn't commissioned properly, if at all, the mains PRV was fully opened with the stopcock left throttled in.