Water Butt Filling Question

[simpic]

Hello,

I have a 175 litre water butt which is filled primarily by a rain water diverter.

This works a treat, empty to full in three hours of rain last night. Whilst we live in a rather wet country I do at some stage in the summer hope that I will be using it more than the rain can fill it!

I would like to plumb in a pipe from the mains water feed to the tank and terminate it with a ball float valve. Something like this... http://www.screwfix.com/p/pegler-prestex-float-valve-part-2/27627

My question is that to make this work only when the tank is nearly empty, the float will have to be submerged under 500 - 600mm of water most of the time. Obviously this will mean the float will want to fly up out of the water. Will the force of the upward pressure cause the valve to fail over time?

Is there another way of achieving the same thing?

Thanks in advance.

 

[HERTS P&D]

Get a hose pipe?

Andy

 

[onecog]

I don't see the point in running a mains supply and then go through all that hassle when you could put a garden tap on the mains pipe and be done

 

[HERTS P&D]

That's what I said! In less words.



Andy

 

[simpic]

Yep, I have a hose pipe!

Maybe I should have highlighted that I wish for this to be an automated solution.

When I mean mains supply I mean from an existing outdoor tap.

 

[kbdiy]

Hello,

My question is that to make this work only when the tank is nearly empty, the float will have to be submerged under 500 - 600mm of water most of the time. Obviously this will mean the float will want to fly up out of the water. Will the force of the upward pressure cause the valve to fail over time?

I don't think so. If the float is at the bottom it will shut-off the supply as soon as it rises, hence you will still have a near-empty water butt. Plus all the issues around frost protection. Much easier to stick to a hosepipe.

 

[rjm2k]

Some things simply don't need to be done

 

[muggles]

If you install a ball valve, won't your water butt refill with mains every time you fill a watering can, thereby removing any capacity for rainwater? Also, you have to turn a tap on to draw water from your water butt so why not just go to the outside tap and fill there when the butt runs out? The effort is the same.

You'll need all sorts of backflow prevention measures if you really do want to put mains into your water butt, especially if you want to submerge the ball valve.

 

[simpic]

If you install a ball valve, won't your water butt refill with mains every time you fill a watering can, thereby removing any capacity for rainwater? Also, you have to turn a tap on to draw water from your water butt so why not just go to the outside tap and fill there when the butt runs out? The effort is the same.

You'll need all sorts of backflow prevention measures if you really do want to put mains into your water butt, especially if you want to submerge the ball valve.

The tank feeds a irrigation system feed by a pump. No watering cans or the like will be filled from the tank, only the pump connected to the solenoid valves connected to the sprinklers. These are all controlled via an automatic timer and rain sensor. Hence the need for this to be automated so the pump does not run dry.

I am planning on installing the valve 3/4 of the way down the tank so there is still enough water to do a cycle of watering but plenty of room for the tank to be filled up by the rain. Hence the question about the ball float being submerged and the effect on the valve.

 

[virgilns]

Crazy ideas...LOVE THEM!

Either reduce the voume of the ball (or part fill it with water and reseal it) or hsorted the length of the arm...a lot. Some ball valves have a ball attchement that slide up and down the shaft...can just slide this up and cut of he surplus.

You might also want to check how much drop the ball needs in order to operate the valve and then set it just higher than this to give you more 'rain water' space whilst keeping the auto top up working.

Also if you find that the ball valve doesn't refill the 'but as quickly as you need (with a lower 'no rain' level), you can 'T' two ball valves off the same feed pipe to provide a faster fill (I did this in my first flat when the cold water tank wasn't man enough for the power shower and would empty!

 

[danplumb]

im sure we`ll have enough rain for you to worry about that, why not just get another water butt and link them together so you have twice the volume ?

 

[simpic]

Crazy ideas...LOVE THEM!

Either reduce the voume of the ball (or part fill it with water and reseal it) or hsorted the length of the arm...a lot. Some ball valves have a ball attchement that slide up and down the shaft...can just slide this up and cut of he surplus.

You might also want to check how much drop the ball needs in order to operate the valve and then set it just higher than this to give you more 'rain water' space whilst keeping the auto top up working.

Also if you find that the ball valve doesn't refill the 'but as quickly as you need (with a lower 'no rain' level), you can 'T' two ball valves off the same feed pipe to provide a faster fill (I did this in my first flat when the cold water tank wasn't man enough for the power shower and would empty!

Thanks for the ideas virgilns, I'll bear them in mind, especially the refill rate.

danplumb, unfortunately I do not have the space where the tank is to add another, or bigger one.

 

[Onetap]

Is there another way of achieving the same thing?

It's done with float switches for pumps (e.g., low level switch starts pump, high level switch stops pump), so you could set up a similar system to operate a solenoid valve. It would need a relay in a waterproof box. I'd use a low voltage outdoors; there are battery-powered timed irrigation devices, so batteries could work if you find a suitable solenoid valve.

I'd still have a float valve on it as a safeguard, having been embarrassed by a solenoid valve once before.

 

[muggles]

I'm going to wave my arms about backflow prevention again as it seems to have been missed last time, so here goes with the simple version...

You cannot legally have a submerged mains outlet in a rainwater tank, it contravenes water regulations and will lead to a heavy fine if the water main fails and sucks rainwater back into the mains pipework.

 

[Onetap]

You cannot legally have a submerged mains outlet in a rainwater tank, it contravenes water regulations............

True.

The float switch & solenoid valve arrangement could stop the water flow, whilst keeping the water level below the overflow and the inlet. Keeping the inlet above the overflow level would maintain an airgap and (I think, but you'd have to check the Water Regulations to be sure) comply with the Regulations. I'd still have a float valve on the inlet as a safety device, set to stop the water below the overflow level if the solenoid valve failed.

Solenoid valves are liable to jam open if there is any grit in the incoming water. Thames Water disturbed the connection from the mains to my house a couple of months ago. I saw the contractors at work and suspecting what might happen, shut off the incoming stopcock, thinking my neighbours could have the first share of any dirt that got into the pipes.

Unfortunately, it was just my service pipe they were working on/vandalising, so when I turned on the stopcock, the water from the kitchen tap was brown. I'd forgotten to shut off the riser and it wrecked a Torbeck float valve.