Attic conversion - tank moved - maintain pressure

m0nsterie

Hi,
I'm having work done on my attic to make more storage space (steel in, trusses removed etc.) and part of the work will be to move the water tanks from the centre of the attic out to the eaves. A plumber will be doing this as part of the job.

My tank is currently almost exactly 1 meter above the gravity-fed shower outlet. I like the pressure as it is and would like to maintain it as much as possible. Pushing the current tanks out to the eaves means losing height and therefore pressure. I think the normal workaround for this is to add a pump, which I would like to avoid (noise, extra potential for issues etc.). At the moment (have not met the plumber, only the builder) this is the only suggestion given to me.

So, any suggestions? My current tanks (it's two tanks, joined with a pipe) are each approx 25 inches high X 24 inches wide X 37 inches long.

I can't say yet exactly how much height I will lose as it will depend on where the steel beams go in.

Main thing I am thinking of is lower profile tanks (not as tall) so that I can lift them up higher in the eaves - has anyone experience of this? Can you think of any issues? Any problems with smaller tanks (less water available when mains goes off for example)? If you've done this, where's best to source these tanks in Dublin?

Thanks

corkgsxr

Instead of eves can you move to end if attic and lift it right up to roof level

m0nsterie

corkgsxr wrote: »

Instead of eves can you move to end if attic and lift it right up to roof level

Unfortunately it's a hip roof semi detached so has eaves on three sides. If I put it in the open space then it takes away a good bit of my useable space.

Full tanks are very heavy so I guess that's why they are usually placed on supports closer to the attic floor (am I right?) rather than up at roof level.

Wearb

Have you considered multiple smaller tanks linked.

GreeBo

m0nsterie wrote: »

Unfortunately it's a hip roof semi detached so has eaves on three sides. If I put it in the open space then it takes away a good bit of my useable space.

Full tanks are very heavy so I guess that's why they are usually placed on supports closer to the attic floor (am I right?) rather than up at roof level.

It weighs the same whether or not its on the floor or the ceiling.

One of these
https://www.tanks.ie/water-tanks/water-storage-tanks/attic-water-tanks/closet-attic-water-tank.html

Would take up less space.

m0nsterie

Wearb wrote: »

Have you considered multiple smaller tanks linked.

This is what I'd like to get some more info on. Ideally lower profile (lower height) tanks so that I could lift them higher. Anywhere in Dublin I could get those?

Thanks

m0nsterie

GreeBo wrote: »

It weighs the same whether or not its on the floor or the ceiling.

One of these
https://www.tanks.ie/water-tanks/water-storage-tanks/attic-water-tanks/closet-attic-water-tank.html

Would take up less space.

Haha, thanks. It weighs the same but the structure needed to support it is easier to manage at floor level (330 litres of water = 330 kilograms). I'd like to maximise the useable (standing) space in the attic.

I've seen those closet water tanks - they're taller than a normal tank. I'm looking for something lower that could maybe go into the eaves but pushed up high into the eaves to give more pressure.

tommythecat

m0nsterie wrote: »

Haha, thanks. It weighs the same but the structure needed to support it is easier to manage at floor level (330 litres of water = 330 kilograms). I'd like to maximise the useable (standing) space in the attic.

I've seen those closet water tanks - they're taller than a normal tank. I'm looking for something lower that could maybe go into the eaves but pushed up high into the eaves to give more pressure.

We did our attic conversion last year and had similar issues.had to install a pump. It's not too loud. You get used to it.

m0nsterie

tommythecat wrote: »

We did our attic conversion last year and had similar issues.had to install a pump. It's not too loud. You get used to it.

Thanks - did you try it out before installing the pump or was it just recommended and you took a hot and cold feed into the pump? If I stick the tanks at floor level in the attic I'd be losing about 60-70cm height out of the 1 metre height I have above the shower. So 60-70% pressure loss.

Maybe I'll leave them in the open space rather than the eaves.

It's just hard to visualise the space before the work is done.

John.G

If the shower head is your only concern you could install a Triton AS2000XT tank fed shower which has its own integral pump and will give up to 14 LPM (power shower) and feed everything else as before since the head pressure isn't of such concern?.
There is a newer and quieter version of this Triton, sleeper12 will advise.

This is the one....Novel Silent Running Thermostatic Power Shower

Sleeper12

John.G wrote:

This is the one....Novel Silent Running Thermostatic Power Shower

Great little shower. 14 litres per minute in almost silence due to the silent motor. It won't break the bank

m0nsterie

John.G wrote: »

If the shower head is your only concern you could install a Triton AS2000XT tank fed shower which has its own integral pump and will give up to 14 LPM (power shower) and feed everything else as before since the head pressure isn't of such concern?.
There is a newer and quieter version of this Triton, sleeper12 will advise.

This is the one....Novel Silent Running Thermostatic Power Shower

Sleeper12 wrote: »

Great little shower. 14 litres per minute in almost silence due to the silent motor. It won't break the bank

Thanks both, it does sound good. But it would require pulling out my existing shower + replacing shower tiles/panels etc. I have a mixer in the wall and shower head comes out of the wall.

Sleeper12

m0nsterie wrote: »

Thanks both, it does sound good. But it would require pulling out my existing shower + replacing shower tiles/panels etc. I have a mixer in the wall and shower head comes out of the wall.

If it's going on a stud partition it should be possible to get a new hot & cold feed along with a cable down from the attic without damaging any tiles. You could then leave the old shower in place. If you really wanted to remove the old shower then the Triton Novel might cover the footprint as it's a largeish shower

tommythecat

m0nsterie wrote: »

Thanks - did you try it out before installing the pump or was it just recommended and you took a hot and cold feed into the pump? If I stick the tanks at floor level in the attic I'd be losing about 60-70cm height out of the 1 metre height I have above the shower. So 60-70% pressure loss.

Maybe I'll leave them in the open space rather than the eaves.

It's just hard to visualise the space before the work is done.

The plumber set it up in such a way that I could turn a lever to bypass the pump. The difference was very noticeable.

John.G

m0nsterie wrote: »

Hi,
I'm having work done on my attic to make more storage space (steel in, trusses removed etc.) and part of the work will be to move the water tanks from the centre of the attic out to the eaves. A plumber will be doing this as part of the job.

My tank is currently almost exactly 1 meter above the gravity-fed shower outlet. I like the pressure as it is and would like to maintain it as much as possible. Pushing the current tanks out to the eaves means losing height and therefore pressure. I think the normal workaround for this is to add a pump, which I would like to avoid (noise, extra potential for issues etc.). At the moment (have not met the plumber, only the builder) this is the only suggestion given to me.

So, any suggestions? My current tanks (it's two tanks, joined with a pipe) are each approx 25 inches high X 24 inches wide X 37 inches long.

I can't say yet exactly how much height I will lose as it will depend on where the steel beams go in.

Main thing I am thinking of is lower profile tanks (not as tall) so that I can lift them up higher in the eaves - has anyone experience of this? Can you think of any issues? Any problems with smaller tanks (less water available when mains goes off for example)? If you've done this, where's best to source these tanks in Dublin?

Thanks

Just to be clear on this, if you move or install new tanks in the eves, will the tank bottoms be at the same level as before? if so, then assuming that the 24" (0.6M) high existing tanks are full to the brim and your new tank has effectively a 12" (0.3M) water level then you are only losing 0.3M so you may have a effective head of say 0.7M vs 1M previously so the flowrate will be the sq.rt of (0.7/1.0) or 84% of original.
If however the tank(s) repositioning results in the water levels being only 0.4M instead of 1m then the flowrate will "only" be, but still, 63% (sq.rt of (0.4/1)) of the original flow rate.

m0nsterie

John.G wrote: »

Just to be clear on this, if you move or install new tanks in the eves, will the tank bottoms be at the same level as before? if so, then assuming that the 24" (0.6M) high existing tanks are full to the brim and your new tank has effectively a 12" (0.3M) water level then you are only losing 0.3M so you may have a effective head of say 0.7M vs 1M previously so the flowrate will be the sq.rt of (0.7/1.0) or 84% of original.
If however the tank(s) repositioning results in the water levels being only 0.4M instead of 1m then the flowrate will "only" be, but still, 63% (sq.rt of (0.4/1)) of the original flow rate.

Currently the bottom of the tank is 70cm above the ceiling.

Future - the eaves being lower necessitates the bottom of the tank being closer to the ceiling. So say 0cm above the ceiling for sake of calculation.

You are talking about flowrate and measuring from the top of the water level.

I am talking about pressure which (correct me if I am wrong) is measured from the outlet (near bottom) of tank. Using my figures I'd be losing 70% of the pressure (as my showerhead is 30cm below the ceiling currently, so is 1 metre below the bottom of the tank at the moment).

Can you explain the real world difference between flow rate and pressure? Bottom of tank always taken for pressure calcs as far as I can see.

My hope would be to get shorter (low profile) tanks so that the bottom of the tank can be greater than 0cm above ceiling.

Thanks

m0nsterie

Also forgot I can't just push the tank as high as possible in the space as access room would be needed

John.G

The actual/real head is from the tank water surface to (in your case) the shower head, if you assume 18” (0.46M) as the water level in the existing tank then the head is 0.46M+0.7M+0.3M, 1.46M, if you install a new tank(s) on the ceiling with the same water level then the head is 0.46M+0.3M, 0.76M, and because flow rate is proportional to the sq.rt of head, then the new flow rate will be, sq.rt(0.76/1.46)*100, 72% of the original, assuming in both cases that the water level is maintained in the tank, but even if it isn’t the 72% value should still be near enough.

So once you know or can calculate the distance from the water level in the proposed tank(s) to the shower head, you can calculate the new flowrate, as above.

I have a coffin type CWST of ~ 125 litres and the height (just measured now) from the water level to the shower head is 0.8M with tank sitting on the "ceiling". The tank dimensions are ~ 1200mm(L) X 465mm(W) X 450MM(H).

GreeBo

^ this.
Hence why you should get one of those vertical tanks I posted.
Unless you are draining the tank to empty your pressure will be the same if not better then before and they take up much less room

m0nsterie

John.G wrote: »

So once you know or can calculate the distance from the water level in the proposed tank(s) to the shower head, you can calculate the new flowrate, as above.

Thanks, that's very helpful.

So just to clarify for myself, is "flowrate" what non-plumbers would call "pressure", i.e. how "powerful" the shower is? I know I've mixed 3 technical terms there but just in layman's terms... are they the same? thanks

John.G

Flowrate is what matters but you won't get flowrate without the pressure to drive the water through the pipework and the showerhead or tap or whatever, that pressure can be supplied by gravity (in your shower head case) or it can be supplied with a pump.

If you want to carry out a test on your existing shower, put the shower on at your normal settings and hold a dish underneath it for exactly I minute then measure this amount into a 1 litre milk bottle, if the bottle has to be filled 10 times then the flow rate is 10 litres/min, if the bottle only has to be filled 5.5 times then the flowrate is 5.5 litres/min and so on. If you change the head by repositioning the tanks or installing new tanks then the 10 litres/min flowrate would fall to 7.2 litres/min and/or the 5.5 litres/min would fall to 4 litres/min.

A shower with a flowrate exceeding say 10 litres/min would be considered a "powerful" shower whereas less than 5 lires/min may be considered a poor flow but the normal electric shower only flows 3 to 4litres/min (at 40C) and a lot of people are perfectly happy with it. (like myself)

Irish_peppa

My sister had this done and had same set up as you.
Two large connected tanks in centre of attic (also hipped roof)
The plumber removed the 2 large tanks completely and replaced with 1 only coffin type tank that fit snug into the eve.
Similar to this https://www.tanks.ie/water-tanks/water-storage-tanks/attic-water-tanks/slim-80-60-attic-water-tank.html

No idea what the second tank was for anyway as it looked like the water in it was stagnant so it defintely wasnt drinking water:eek: ( i hope)

John.G

GreeBo wrote: »

^ this.
Hence why you should get one of those vertical tanks I posted.
Unless you are draining the tank to empty your pressure will be the same if not better then before and they take up much less room

The vertical tank would be a excellent choice IF he can get enough head room as it could make up for the 0.7M head loss (or some of it, at least) and even though it has a much smaller footprint then the steelwork should be able to support it??

Also see my edited post #18, above