Raising attic cold water tank?

[Neoscan]

The water to my bathroom has always been a problem, especially the cold water tap which often gets air locks in it. Occasionally the toilet cistern stops filling too.
I’ve been advised that the reason for this is that cold water tank in my attic (4th floor flat) is only sitting on the ceiling joists and hence, is not high enough up (the water pipes come out horizontally and there isn’t enough downward pressure apparently).
Does this sound like it could be correct? And how do I go about raising it? Would a 1.5 metre raise make much difference?

 

[HERTS P&D]

Easier to fit a booster pump.

Andy

 

[Neoscan]

Yeah, I had wondered about that too. I shall investigate

 

[fixitflav]

The water to my bathroom has always been a problem, especially the cold water tap which often gets air locks in it. Occasionally the toilet cistern stops filling too.
I’ve been advised that the reason for this is that cold water tank in my attic (4th floor flat) is only sitting on the ceiling joists and hence, is not high enough up (the water pipes come out horizontally and there isn’t enough downward pressure apparently).
Does this sound like it could be correct? And how do I go about raising it? Would a 1.5 metre raise make much difference?

I think there are other problems. If the CWST is say 0.5m deep and sitting on the joists, you've got about 2m head from water level to taps. That's usually enough.

 

[Neoscan]

I think there are other problems. If the CWST is say 0.5m deep and sitting on the joists, you've got about 2m head from water level to taps. That's usually enough.

That’s true. I thought there would be enough height but the pipes coming out of CWST are horizontal for a couple of metres and I think this is where the airlock problems are occurring.
The hot water tap in the kitchen has never had good pressure either but I assumed this was because the HWST in the cupboard was at floor level.
I wish I could find whoever did the pip work in this place- I’d certainly my being having a few words with them!

 

[JohnD]

When you look at the cold water tank

how big is it?

how full is it?

is there a valve on the outlet?

Is there any sign of dirt, fluff, drowned wildlife or scraps of insulation in it?

What size is the pipe that comes out and runs to your hot water cylinder?

 

[fixitflav]

That’s true. I thought there would be enough height but the pipes coming out of CWST are horizontal for a couple of metres and I think this is where the airlock problems are occurring.
The hot water tap in the kitchen has never had good pressure either but I assumed this was because the HWST in the cupboard was at floor level.
I wish I could find whoever did the pip work in this place- I’d certainly my being having a few words with them!

I'm surprised airlocks come back once cleared. Or why 2m horizontal would be a problem. As JohnD said, worth checking for dead pigeons in the tank! You could try backflushing from the mains.
The level of the HWST makes no difference, pressure at the taps is still determined by the level of the CWST.

 

[Neoscan]

Hi,
Sorry for the delay in reply- I had to escape the city for a few days.

So, the CWST in the attic is approx 114 litres/ 25 gallons with 28mm pipes x2 coming from it, sitting just above ceiling level. When I went to check, it wasn’t completely sealed but there wasn’t any large debris, dead pigeons, bits of insulation, etc in there. Perhaps some very light sediment on the bottom of it. It gets to about 4/5s full.

Blowing air back through the system from the bathroom results in the toilet cistern filling and working but that only lasts for a few hours before it stops again completely (it would perhaps make sense to think something was floating and blocking it in the CWST but there isn’t) . I can’t seem to get more than a trickle from the bathroom cold tap and that stops too. The cold tap had had a few similar issues in the past with apparent air locks or similar but the toilet flush has always worked.

I can’t figure this out at all! My next plan is to open the CWST and put a hosepipe directly from the mains input in it to the outlet pipes to see it that clears things.

Any other tips? I’m all out of ideas!

Thanks!

 

[HERTS P&D]

Your tank is too small and is emptying faster than it fills. You need at 50 gallon tank.

Andy

 

[Neoscan]

Thanks Andy. I’m going to double check that size as 25 gallons is very small. I may have miscalculated. Will measure it again tomorrow.

 

[HERTS P&D]

1190 X 610 X 500MM (50 gallon)

Or post a picture of yours.

Check the float valve is working at full pressure when you push the arm down.

Andy

 

[Neoscan]

These are the only pics I have but will measure and take more tomorrow.
Yes, it fills with good pressure when float valve is pressed down. Excuse the 230 years worth of dust!