gravity fed toilets?

[Fred]

Hi,

As you may have read in my other posts, I am considering replumbing the water. I thought that while I have the floorboards up, I might change the toilets to fill from the cold water tank rather than the mains.

I know that 99.9% of the time this is unnecessary but recently our water was cut off unexpectedly and my first thought was how can I have a cup of tea and my second was, what if someone needs the toilet?

I know some people here have done this. What was your experience? Does it dramatically slow the time taken to refill the cistern? That could be a concern because we have those silly water saving toilets that require more than one flush, so don't save water! Do you remove the flow restrictor (or whatever it is called) from the inlet?

Would it be a good idea to run as much as possible in 22mm pipe to increase flow? Is there a chart somewhere showing flow rates for different pipe diameters (I realise it will be affected by the number of turns and tees etc) or will 15mm be good enough?

TIA

[harryagain]

It was once common practice to do this. You will need a low pressure jet on your float valve so it fills in reasonable time. It has a bigger hole in the jet. Or drill out your existing jet (sopposing there is enough "meat on it")

[Brian Gaff]

Chuckle, only when, as I have you forget to put the right valve in and it trickles away for a quarter of an hour or so sounding like an incontinent Rhino.. Brian

[Dave Liquorice]

No, use the loo as normal following the if "it's yellow let mellow, if it's brown flush it down" maxim and fill the bucket from a tank fed tap and use that to flush the loo. You have a tank fed tap so you can have a cup of tea. B-)

How long is a piece of string? All our water is tank fed, loos don't take a long time to fill but then we don't have to flush twice. 1/2" Torbeck valves with no flow restrictor IIRC. You have checked that there isn't some form of short/long flush system you haven't worked out?

[km]

I should think that most people have moved the other way. The old-fashioned tank in the loft put a fair old weight on the beams, accumulated all sorts of junk and most annoyingly caused the WC to refill at an annoyingly slow rate.

km

[Jethro_uk]

That said, if you could harvest rainwater, and draw that up into a tank just for loo-flushing, you'd probably save a fortune.

[robgraham]

Think of the cross section of a 15mm pipe and that of the cistern control valve, and you will realise that even a 10mm pipe would be quite adequate.

In fact if you google on "pipe size flow rates" - always good to do your home work first IMO - you will find that the flow rate for a cistern is 100ml /sec, which is probably not much more than your pissing rate, and do you pee out of a 15mm pipe?

Rob

[Nightjar]

I always refill my kettle after use.

I've never lived in a house that has had a mains fed loo. You just need the inlet valve to be set for a low pressure supply, which may involve removing a restrictor or fitting a different nozzle.

Grey water can be used for flushing the loo too.

Colin Bignell

[Bill]

In message , Brian Gaff writes

It is just as much fun when you fit a low pressure fitting on a high pressure feed. It fills VERY rapidly, apart from the water that sprays all over the room of course. A mistake I made early on in life and one hopefully not to be repeated.

PS I have never, ever, wondered what an incontinent Rhino sounded like, but now I know, thank you for that piece of knowledge.

PPS How do you know what an incontinent Rhino sounds like???

[John Rumm]

Pros of gravity feed, less condensation on the cistern (the water is warmer), and its a quieter fill. Down side, can take *ages* to fill depending on how much head it has.

If there is a flow restriction, then it can be removed.

15 will be more than adequate for this application.

[The Natural Philosopher]

basically you don't flush, but once. It helps to have several toilets in the house.

[matthelliwell]

Fill a bucket from a tap plumbed into the cold water tank, pour into cistern and flush. Replumbing sounds like an awful lot of work to avoid carrying the occasional bucket of water.

[Andy Dingley]

No.

IMHO, all toilet cisterns should use a Torbeck valve, or some other design that fills at full bore and only starts to throttle the flow when nearly full. That makes more difference to fill times.

Either remove, or swap to the correct nozzle. Pipe diameter should already be fine too.

Just don't install a loft conversion bedroom with an on-suite and then plumb the toilet cistern into a CW tank that's now _below_ the level of the toilet. That took a neighbour a surprisingly long time to work out.

[Fred]

Sorry, I perhaps didn't make it clear that I was hoping to feed both upstairs and downstairs toilets. I'm sure 15mm would be fine for one but would it be ok for two? I found a page on the internet about flow and it seems to suggest a cistern needs 0.1L/s and that 15mm pipe can carry 0.22 L/s quietly, so hopefully it is just within limits.

[Brian Gaff]

You needed to have watched all those natural history shows in the 70s...

Brian

[Fred]

I did consider those options ;)

Do you not have fresh water to drink?

These are torbecks too, with a spiral restrictor which I was planning to remove.

They do not need two flushes all the time, it's just that the water saving and the strange geometry of the toilet sometimes means a second flush is necessary IYSWIM. This is what happens when you buy a suite from a catalogue. Next time I will look at a display model and lift the lid to look first.

Thanks.

[Fred]

Well in my case the tank is there for the bath and shower so the weight is present whether I use it for the toilets or not. It has a well fitting lid to stop anything getting in, so it should be ok in that regard.

[Fred]

I think it is said 1/3 of your water is used for the toilet, so if true, there would be savings but the problem is how to get the rainwater into a tank in the loft.

[Fred]

But can it be stored for long or would it start to go smelly?

[Fred]

I think the length of the pipe is important though. I don't think a long run in microbore would work.

There is a web site I have seen recommended here before. Copper something or other. I was hoping someone would remind me what it was, if I had remembered correctly. Is that the site you had found?