Block of flats

[wildejamey]

I live in a block of 27 flats, built 1960s, owners with share of freehold, we appoint a Management Company to deal with utilities etc.

Several flats - including mine - have been experiencing interrupted supply and water then bursting from taps when turned on.
We raised this with a Management Company committee member. Initially a plumber investigated and said it was caused by air in the main cistern serving the building.

Some alterations were made to the cistern pipes but the problem continues. Now we are being told it's because lots of flats have installed combi boilers (instead of the old tank systems) and that the plumbers failed to put the right diameter pipes in the individual combis.
Seems a bit far-fetched. So far as I'm aware these days plumbers invariably recommend changing to combi boilers and it seems to me the real problem is that the main water system for the whole building needs updating to accommodate the use of combi boilers?

Who is right? The committe members are reluctant to pay as they still have the old boilers and say they don't have any problem!
Before getting a plumber to change my pipes I want to be sure it's not a waste of time and it's the building that needs upgrading.
Any ideas?
Thanks.

 

[Mike Jackson]

It does sound as though the cold main is not large enough to cope with the demand from all these combis.

 

[Joncpi]

There are possibly a number of things to investigate.

Do you have mains fed taps? Is it both hot and cold taps that get air in them? If the hot is low pressure, i.e. tank fed, and is getting air in it then at some point the outlet from the tank must be uncovered to allow the air in.

So possibly the combi boilers, which will be mains fed are taking too much water from the main and there is not enough water filling the tank. So the main is undersized.

If both taps are low pressure and get air in, again it is the outlet from the tank. If the cold tap is mains fed and gets air in then it could again be no water getting up to the tank ball valve and air being dragged into the pipe. Again the main is undersized. This is assuming there is one main supplying the whole block.

How do you pay fror your water? Do you each have seperate meters? Or seperate supplies from the road?
To check if your taps are mains or low pressure, if you have a seperate incoming mains water stopcock and shut it off, see which taps you lose, is it one that gets air in it?. Or you can put the palm of you hand tightly under a tap to "close off" the outlet, then turn on the tap. You may get wet here.
If you can feel the pressure and cannot hold back the water, it's mains fed. If you do not really feel any pressure and can hold the water back then it's tank fed.

This is only very rough guide, normally a tank in the roof will only give about 1.0bar pressure to a downstairs tap (32 feet head gives about 1.0 bar pressure). Your mains pressure should be higher than this as most Water Authorities guarantee a minimum of 1.0bar, but this is not always the case.
Alternatively you could go to the expense of actually connecting a pressure gauge to the pipes to measure the actual pressure.

These flats that are experiencing the same problem, are they all on the same floor?

 

[steadyon]

Worth checking the lease. Some blocks of flats do not allow the installation of combi boilers because they can cause the problems you've identified. If leaseholders have installed combis against the terms of their leases they can be made to remove them.

 

[wildejamey]

Thanks. So I suspect the cold main is obsolete and needs replacing.

 

[wildejamey]

Thanks for that contribution. The lease was drawn up in the 1960s, which I suspect was before combi boilers were ever heard of. I think if new technology comes along, one needs to go with the flow (if u will pardon the pun) and upgrade the main system rather than retain boilers that went out with the ark for which no parts are any longer made

 

[wildejamey]

Thanks Joncpi that is very helpful and food for thought. I am only aware of the situation on the two top floors which is where I and a friend of mine live. The airlocks and interrupted supplies seem to occur in all taps, kitchen and bathroom. The layout is that kitchen and bathroom are adjacent. I am pretty certain the kitchen taps at least are mains fed. When I bought the place I was told there were two separate feeds, one to the kitchen and one to the bathroom - which could correspond to the mains for the kitchen and the roof tank for the bathroom supply. That seems logical. I believe Thames Water apportions bills according to the number of people in each flat as they could not install individual meters. It sounds like as you say the main is undersized. That seems to fit the problem best. The question is whether this is something Thames Water should deal with or the leaseholders/management company?

 

[wildejamey]

Thanks Mike, that seems to be the consensus. But is the Water Company or the Management Company of the block responsible for resolving the problem?

 

[Mike Jackson]

I would expect the water company to have responsibility up to the main stop tap in the building, from there on in it would be the responsibility of the freeholder.

 

[tamz]

The incoming main would have been sized to feed one tap in each flat and feed the tank in the roof. The bathrooms would have been fed from the tank.
If the majority change to combi's they are cutting off their tank supply and drawing the whole house direct from the main. The main is now undersized which will lead to trouble on the higher flats as they will be starved of water at peak times.
Solution
New upgraded main which although it is a big job, split between 27 houses will not be too bad.
It is the managements or tenents responsibility. Nothing to do with the supplier. Combi's were unheard of when these flats were built.

 

[Joncpi]

I agree it sounds as though the main service is now undersized. The cost of upgrading will be down to the tenants or managements as Tamz says, and I agree the cost split between 27 should not be too bad. However getting all 27 to cough up can be tricky. Best let your managing agents deal with this. It could be "sold" to the other tenants by pointing out that the hot water provided through their combi boilers will have a better flow rate when the works are finished, and less likely to fluctuate as it is probably doing now.
Also there is no danger of them losing water and the risk of damage to their boilers. Yes, you and I know there are safeties but they may not.

 

[wildejamey]

Thanks Tamz
That is a very interesting reply and seems to tick all the boxes. I will now put this to the Management Committee and see what the response is.