Water tanks in the attic

[attrayant]

There are many small (4-6 story) apartment buildings in my area that have water tanks sitting on their roofs. Careful eyeball calculation suggests that the bottom of the tank can't be more than a meter above the shower heads of the top floor dwellings. That would be 1-2 PSI at most. Would water even spray from a shower head at that pressure, or would it mostly dribble?

I've wanted to put tanks in my attic for a while because I hate the sound of the pumps (there are two - one on each side of the house) constantly cycling on and off every few seconds as they struggle to keep a constant pressure in the line. I'm just not sure what kind of miserable should experience I would be trading for it.

Another possibility is getting a single, smaller (and quieter) pump that runs only the 2nd floor showers. 2nd floor sink taps and the 1st floor (showers included) would probably be okay at street pressure, ya think?

How have you managed the water pressure in your home?

[KunMatt]

We have a constant water pressure pump outside next to the water tank about 20m away from the furthest bathroom. If I take off the hose from the shower faucet it will spray water horizontally and hit the wall at about the same height 2m away.

Edited May 2, 2015 by KunMatt

[KunMatt]

double post please delete mods.

Edited May 2, 2015 by KunMatt

[attrayant]

Another reason for attic water tanks is getting rid of the pumps all together (and thus saving electricity).

Google image search for "attic water tanks" shows that people definitely do this, although there could still be a pump after the tank that's not shown in the picture.

Oh that takes me back. I miss copper pipes and brass fittings so much.

Edited May 2, 2015 by attrayant

[KunMatt]

Yes I remember planning it all at the time. I basically had the choice to build our house with water tanks in the attic already or make a massive access hatch so they could be carried up, but I figured an even better way would be to build a really high tank tower specifically so we could raise the tanks so much higher than the house that we would get good pressure. Or we could spend 6,000 baht on a constant pressure pump that is so powerful I have to open the faucet about 20% of the way so the water pressure wouldn't be so powerful.

A constant pressure pump was the easiest, cheapest and most convenient method for our house.

[bankruatsteve]

Unless your "city" water pressure is enough to fill a tank in the attic, you will need a pump to do it. A tank in the attic will not provide much pressure - like for showers. So, WHY would you want to do that vs. a tank and a pressure pump at ground level? BTW: A tank in the attic will have support issues.

[Naam]

How have you managed the water pressure in your home?

with a pressure tank.

[attrayant]

The concrete/rebar load bearing columns are easily accessible in the attic. I'd need to build a suitable platform on those of course.

Yes the existing street pressure can run two 2nd floor sinks just fine. If an overhead tank with only 2-3 meters of head won't be sufficient to drive even a low-flow shower head, there's always the option to mount a single small pump just for the upstairs showers and let the tanks gravity-feed everything on the 1st floor.

[Naam]

Yes I remember planning it all at the time. I basically had the choice to build our house with water tanks in the attic already or make a massive access hatch so they could be carried up, but I figured an even better way would be to build a really high tank tower specifically so we could raise the tanks so much higher than the house that we would get good pressure. Or we could spend 6,000 baht on a constant pressure pump that is so powerful I have to open the faucet about 20% of the way so the water pressure wouldn't be so powerful.

A constant pressure pump was the easiest, cheapest and most convenient method for our house.

using a pressure tank there's no need for a constant pressure pump.

by the way, 6,000 Baht buys you a toy and not a pump that delivers constantly "powerful" pressure. moreover, the water pressure is not reduced by partially opening a faucet. what you reduce is only the flow volume.

but a combination of a simple 1hp pump and a pressure tank will deliver whatever powerful pressure and flow (both adjustable) you desire and the total cost won't exceed 6,000 Baht.

[Naam]

The concrete/rebar load bearing columns are easily accessible in the attic. I'd need to build a suitable platform on those of course.

Yes the existing street pressure can run two 2nd floor sinks just fine. If an overhead tank with only 2-3 meters of head won't be sufficient to drive even a low-flow shower head, there's always the option to mount a single small pump just for the upstairs showers and let the tanks gravity-feed everything on the 1st floor.

instant water heaters will not work with your planned set-up!

[Anthony5]

Yes I remember planning it all at the time. I basically had the choice to build our house with water tanks in the attic already or make a massive access hatch so they could be carried up, but I figured an even better way would be to build a really high tank tower specifically so we could raise the tanks so much higher than the house that we would get good pressure. Or we could spend 6,000 baht on a constant pressure pump that is so powerful I have to open the faucet about 20% of the way so the water pressure wouldn't be so powerful.

A constant pressure pump was the easiest, cheapest and most convenient method for our house.

using a pressure tank there's no need for a constant pressure pump.

by the way, 6,000 Baht buys you a toy and not a pump that delivers constantly "powerful" pressure. moreover, the water pressure is not reduced by partially opening a faucet. what you reduce is only the flow volume.

but a combination of a simple 1hp pump and a pressure tank will deliver whatever powerful pressure and flow (both adjustable) you desire and the total cost won't exceed 6,000 Baht.

How do you control that 1hp pump to switch on and off Naam, as they usually don't have a pressure switch.

[attrayant]

I wonder if those are pressure tanks I'm seeing on the tops of apartment buildings rather than water pumps.

I initially considered a pressurized tank but my brain is almost always operating in the minimalist "get rid of unnecessary infrastructure" mode and not the "rip-and-replace existing infrastructure with new infrastructure" mode. In other words, if I can't reduce the existing setup to a (mostly) gravity-fed model, I'll probably just stay with what I've got.

Yes I know that insta-hots (what we call them in the states) need a certain volume of water to pass before they'll switch on to avoid burning out the heating element. I'm not drawing up actual plans here, just kicking the ball around, so to speak.

Edited May 2, 2015 by attrayant

[Crossy]

You do tend to get what you pay for, the low-cost pumps tend to be noisy. Many if not all are peripheral rather than centrifugal pumps (cheaper and no centre seal to burn out if they get run dry), but they do tend to squeal like a stuck pig when working hard

Our (not cheap) Grundfos multi-stage centrifugal pump is almost silent in operation, 1hp provides more than enough flow and pressure

[Naam]

Yes I remember planning it all at the time. I basically had the choice to build our house with water tanks in the attic already or make a massive access hatch so they could be carried up, but I figured an even better way would be to build a really high tank tower specifically so we could raise the tanks so much higher than the house that we would get good pressure. Or we could spend 6,000 baht on a constant pressure pump that is so powerful I have to open the faucet about 20% of the way so the water pressure wouldn't be so powerful.

A constant pressure pump was the easiest, cheapest and most convenient method for our house.

using a pressure tank there's no need for a constant pressure pump.

by the way, 6,000 Baht buys you a toy and not a pump that delivers constantly "powerful" pressure. moreover, the water pressure is not reduced by partially opening a faucet. what you reduce is only the flow volume.

but a combination of a simple 1hp pump and a pressure tank will deliver whatever powerful pressure and flow (both adjustable) you desire and the total cost won't exceed 6,000 Baht.

How do you control that 1hp pump to switch on and off Naam, as they usually don't have a pressure switch.

look at the sketch i posted. besides pump and tank you need of course a pressure switch.

[Naam]

Our (not cheap) Grundfos multi-stage centrifugal pump is almost silent in operation, 1hp provides more than enough flow and pressure

Grundfos = the Rolls among pumps

[sometimewoodworker]

You say

"I hate the sound of the pumps (there are two - one on each side of the house) constantly cycling on and off every few seconds as they struggle to keep a constant pressure in the line."

This almost certainly means that you have a leak in the system, so the first step should be to find it and cure it.

[KunMatt]

You say

"I hate the sound of the pumps (there are two - one on each side of the house) constantly cycling on and off every few seconds as they struggle to keep a constant pressure in the line."

This almost certainly means that you have a leak in the system, so the first step should be to find it and cure it.

Or the pump cylinder needs to be re-pressurised, happened to ours after some time.

[attrayant]

You'll never guess what stumbled upon this morning while rummaging through the inlaws' numerous piles of junk:

"That looks like a pump", I thought to myself. Sure enough, under plastic bags and covered in a thick layer of dust and crud was this:

I'm not sure what the specs are, as the model number that is visible (GTH-24V) appears to be for the tank only. I'll go out later and try to clean it off and get a good look at it.

It appears to have never been used - the threads look virgin. Brother in-law thinks this was bought 3-4 years ago as an irrigation pump for the family farm out in Sa Kaeo but never installed. So it has been rotting on the side of the house under plastic garbage bags all this time.

[Crossy]

and that ^^^ is about 15,000 Baht worth of Grundfos pump

Pretty useless as an irrigation pump, absolutely perfect for your house

You need to install a non-return valve on the inlet side (it comes with the pump but is likely lost) to stop the pressure draining back into your tank.

We have almost the exact same model, pretty well silent in operation.