Cold Water Storage Tank Relocation

[Eng33]

3 bed bungalow built in the early 60's, hot water cylinder in the kitchen airing cupboard, 25 gal cold water tank directly above it in the loft space, sat on the ceiling joists. As I have poor hot water flow, I was planning to mount a new replacement tank (of the same size) as high as possible in the apex of the roof. I would also like to relocate the tank further away from the hot water tank in order to free up some loft space and to get it away from the chimney, as I will be demolishing it in due course. I'm planning a shift of around 4 – 5 metres from it's current location, and will also accompany it with the CH top-up tank.

Can anyone see any potential issues with any of this?

Many thanks.

 

[Lagerkhan]

Just remember the vent needs to rise all the way and the cold feed would like to fall all the way.

 

[ChrisR]

You can get "coffin" style tanks which let you go as high as poss into the ridge. 28mm pipe feeding the HW cylinder can avoid problems.

Consider using Unvented (mains pressure)HW - then you can lose the cistern, or put the cylinder in the loft. Also avoids pumps on shower, gives clean HW, good flow into the kitchen too, ...

 

[TicklyT]

Maintain a difference in the height of the CWS and CH F&E, otherwise a fault (eg HW cylinder coil failure) may go unnoticed until after your radiators have rusted away, and you find you've been bathing in heating system inhibitor.

 

[Eng33]

Many thanks guys, all good advice.

Maintain a difference in the height of the CWS and CH F&E, otherwise a fault (eg HW cylinder coil failure) may go unnoticed until after your radiators have rusted away, and you find you've been bathing in heating system inhibitor.

Not sure I understand the reasoning, can you explain why they need to be at different heights?

 

[stem]

Water in the hot water cylinder is fed from storage tank 1.

Water in the boiler/heating circuit is fed from the smaller storage tank 2. The water in this circuit also supplies the coil inside the hot water cylinder.

Normally the two circuits are completely separate. But if the coil inside the cylinder fails (rare but it does happen) water likes to find its own level, so the tank in the loft that has the highest water level will try fill the other tank until the levels are equal. (usually one tank overflows first unless their overflows are at the same height)

If tank 1 has a higher water level than 2 the clean water will pass from the cylinder through the hole into the coil and the level in tank 2 will rise.

On the other hand, if tank 2 containing the central heating corrosion inhibitor has a higher water level, water containing inhibitor will pass out of the coil and into the cylinder and your hot water that you bathe in.

 

[Bahco]

Consider an instantaneous water heater or a combi if you only have a bungalow.

 

[Eng33]

If tank 1 has a higher water level than 2 the clean water will pass from the cylinder through the hole into the coil and the level in tank 2 will rise.

On the other hand, if tank 2 containing the central heating corrosion inhibitor has a higher water level, water containing inhibitor will pass out of the coil and into the cylinder and your hot water that you bathe in.

Arrrr... got it! Many thanks.

Any benefit going for a bigger tank than my existing 25 gal one?

Also, can't afford to change the boiler for a combi (oil fired anyway) or go to a pressurised hot water tank system.

 

[Nige F]

if your bathroom cold is from the tank.........get a 50 gall. coffin.........if it only feeds the hot cyl. ..then 25 will suffice

 

[Softus]

If tank 1 has a higher water level than 2 the clean water will pass from the cylinder through the hole into the coil and the level in tank 2 will rise.

It's a nice bedtime story, but how many times have you seen an F&E cistern raised up so that its water level is (a) the same as that of the CSC, or (b) higher (!) than that of the CSC?

 

[stem]

If tank 1 has a higher water level than 2 the clean water will pass from the cylinder through the hole into the coil and the level in tank 2 will rise.

It's a nice bedtime story, but how many times have you seen an F&E cistern raised up so that its water level is (a) the same as that of the CSC, or (b) higher (!) than that of the CSC?

erm.......my F&E is higher actually, but I was just answering the question

 

[Softus]

erm.......my F&E is higher actually, but I was just answering the question

Well, I live and learn.

Just curious though - why is your F&E higher?

 

[stem]

When I bought the house the central heating pump although only 18 months old made a terrible noise and sounded as if it was full of air all of the time. After being woken too many times at 5am, I consulted the MI and found that the head was below that specified, so I raised the F&E to suit, and the result was ........... absolutely no change.

In the end I just swopped it for a Grundfoss which is as silent as the grave.

Always intended to get around to raising the other tank but never have.

 

[Softus]

...I raised the F&E to suit, and the result was ........... absolutely no change.

Isn't life a b*tch.

In the end I just swopped it for a Grundfoss which is as silent as the grave.

I'm going to arrange that my grave shouts "FOOK OFF" at anyone who stands on it.

 

[Eng33]

if your bathroom cold is from the tank.........get a 50 gall. coffin.........if it only feeds the hot cyl. ..then 25 will suffice

Thanks for advice, sorry to ask another question..... but what is the reason for a 'normal system' to only have the main supplying the kitchen and outside taps, and the other cold taps coming from the cold water tank?