Very high water consumption

[JX350C]

Hi everyone,

I moved into a new build three bedroom, two bathroom bungalow about 2.5 years ago. Ever since we moved in there has been an issue with the water pressure.

Toward the end of last year the pressure had got worse. For instance, you could not run another tap in the house if a toilet was refilling or if someone was in the shower. If someone was running a bath then all taps in the house would have no water supply to them and the toilets wouldn't refill if flushed until the bath was stopped.

So we telephoned our water provider to see if this is normal for this area or if there were any known issues with the supply in our street.

To our suprise they said that they have noticed that since we have moved into the property that we have been using very high amounts of water.

I can't see us consciously being users of a large amount of water. We have a shower most days and sometimes have a bath instead. We have a dishwasher and washing machine. The dishwasher is used about once a day and the washing machine is only used maybe twice a week at most. The showers we have are mixer type without any power assistance.

The water company have so far been very helpful and asked us to undertake some simple tests to try to identify either a leak or something else in the house using large amounts of water.

The first thing they asked us to do was to ensure the stopcock in the house was fully open. To my surprise I found the stopcock in the house to be only about half open. I thought that when we moved in that this was all setup correctly. I did check the stopcock before calling the water company but I could not turn it. After checking it again following speaking to the water company I managed to turn it until it was fully open. I think it had got a little seized so just needed more brute force to open it fully. Once I had opened it fully, we had full water pressure and we could use the taps at the same time as running a bath or flushing the toilet. The water that came out of the taps and toilet however was brown for a while and it then settled back to clear water.

So the water pressure issue was resolved.

But the water company stated we were using very large amounts of water so we needed to test for a leak between the meter in the street and the stopcock in the house.

So I fully turned off the stopcock and took a meter reading. I waited an hour and checked the meter again and it had not changed. So the water usage was from something or a leak in the house.

So I turned the stopcock fully open again and started to monitor usage by taking regular meter readings.

To my horror I could not believe the difference between the meter readings. Between the readings we did not use any toilets, showers, didn't have any baths and did not have the washing machine or dishwasher on. We didn't use any of the taps so I thought the readings should not change.

The first meter reading that I took, after opening the stopcock in full, was from overnight and it indicated that we had used 130 litres of water overnight.

I've been doing further readings with the stopvalves to individual items closed and without using any water from taps etc.

Overnight last night we have used 394 litres of water. Again, we did not use any showers, toilets, baths or taps during that time.

So with everything off we were still using lots of water for some reason.

So the only thing left that I could think of was the underfloor heating and water heating that is in our laundry cupboard.

So I switched off all the underfloor heating controllers in each room and ensured the manifold actuators were all closed. I then also switched the hot water controller to off instead of it using the timer schedules.

I took a new meter reading and waited an hour and to my suprise we had now only used 3 litres of water. I left it another hour and took another reading and that time we had used 1 litre of water. However, we did not use any taps or any water during that time so even with the heating and hot water off we still have some form of water leak/usage somewhere.

My first concern is why the underfloor heating and/or water heating is using such large amounts of water. Is it normal for underfloor heating to use so much water when it is on?

The underfloor heating and hot water are fed from an air source heat pump.

The hot water is held in a 200 litre cylinder next to the underfloor heating manifolds. We do not have any water tank in the loft.

I'm now going to test the modern dual flush toilets to see if they are using water when they shouldn't be. They appear to be dry around the pan and I can't isolate them easily because the shutoff valves for each toilet has been boxed in.

Unfortunately our landlord did not provide us with any instructions for this heating system in this house so I'm having to learn it as I go along.

Thanks,

Chris

 

[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.