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]

 

[JX350C]

Those are the only photos I have so far. I need to move out our laundry shelving to get pictures of the UFH manifolds and controls and the other pipework. I will try to do that tomorrow and upload them.

Thanks,

Chris

 

[JX350C]

Here are some other photos of the red expansion tank that I have previously taken. I have noticed from these photos that the isolation valves connecting the flex pipe to the cold water feed are in the off position. Should they be in the open position during normal every day use? I haven't noticed this before.

 

[ShaunCorbs]

No you should only open them when you want to refill the heating system by the looks of it you need to

Open one first eg inline with the pipe

Then slowly open the last one until you hear water don’t open it any more watch the pressure guage when it gets just above one shut that valve then shut the other one

 

[JX350C]

No you should only open them when you want to refill the heating system by the looks of it you need to

Open one first eg inline with the pipe

Then slowly open the last one until you hear water don’t open it any more watch the pressure guage when it gets just above one shut that valve then shut the other one

Thanks ShaunCorbs. I will do that.

 

[John.g]

Its probably been months or even a year or so since the last top up so that rules out any part of the heating system as the culprit.

Just to return to the meter, it may be no harm to take a meter reading, then run off some cold water into a 10 or 20 litre drum and note the metered consumption.

 

[JX350C]

Its probably been months or even a year or so since the last top up so that rules out any part of the heating system as the culprit.

Just to return to the meter, it may be no harm to take a meter reading, then run off some cold water into a 10 or 20 litre drum and note the metered consumption.

Thanks John. That is a great idea. I will try that test later today. I am keeping an extended log today and recording meter readings every hour or so and keeping a log of what water we know we used during those times.

 

[plumbingservices]

This is absolutely insane! the underfloor heating controllers should not use this much water.

 

[JX350C]

This is absolutely insane! the underfloor heating controllers should not use this much water.

I agree. The amount of water we are using is insane and something is using water somewhere even when we seem to have things switched off. I've been logging every time we use water and what we used and then taking meter readings roughly every hour to see if the estimated usage matches the meter readings. At the moment I haven't been able to work out exactly what is causing this water usage. Tomorrow I am going to start isolating the DHW, Underfloor heating, showers, toilets (although those are boxed in so I cannot access their isolation valves) to see if I see a drop in usage.

 

[ShaunCorbs]

It’s not the ufh / heating as it’s sealed and won’t refill

 

[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.