Replumbing a toilet cistern

[llykstw]

Hi everyone - hope you can help me as I'm new to plumbing (I'm a DIYer) and want to avoid making any stupid mistakes.

For what it's worth, my toilet is a low-level cistern job, with the cistern and pan connected via a PVC flush pipe with a push-in connector into the pan. The water feed into the cistern is side entry.

The other day, I noticed that the overflow from the cistern has never been connected up. I'm a bit paranoid (having had two floods already in this house) and so I want to connect an overflow in; however, there's nowhere near enough elbow room to drill a hole through the exterior wall and direct the overflow outside, plus the soil stack would probably be in the way. What are my alternatives? Ideally I'd like to connect the toilet overflow to the flush pipe, but I suspect this is a no-no.

At the same time, I'd like to replace the plastic cistern with a new one, because it's looking a bit manky. I intend to install one of the quiet fill valves at the same time instead of the normal ballcock valve - are these types of valves any good?

I also need to drop the cistern down a couple of inches. Is it easy to chop a bit of the flush pipe off to do this, or is it threaded at the top end for connection to the cistern? How do I go about shortening the flush pipe?

All help is very gratefully received!!

 

[peter anderson]

Is your toilet next to your bath? My sister lives in a flat with a bathroom which doesn't have any exterior walls. The overflow on her WC cistern is a plastic pipe which stops over the end of the bath, so if there was an overflow it would go into the bath.

 

[llykstw]

Unfortunately it's not next to the bath, and I couldn't really put a run of pipe in without it looking pretty daft I might be able to tap it into the sink waste pipe above the u-bend though, but presumably if you're not meant to connect the overflow to the flush pipe (as you wouldn't know if the thing's overflowing or not) then connecting it to the sink waste isn't any better!

 

[taydo]

If you fancy changing the syphon you could make it into an internal overflow.

 

[llykstw]

If you fancy changing the syphon you could make it into an internal overflow.

I do fancy this - it sounds like I'd need a special kind of siphon? Can you point to a link showing the type that I'd need please? Also, presumably this means that any overflow in the cistern goes directly down the flush pipe into the pan?

 

[Bas]

Shortening the pipe is straightforward, the connection at the cistern is normally just a push fit. Any good plumbers merchant will sell you an internal overflow syphon - but I would take your old one in some of them have restricted space at the bottom of the cistern. If there is no overflow fitted it may be of course that you already have one! Try it by holding down the ball cock and see if the syphon acts as an overflow. A torbeck valve is a good replacement for the ball cock - takes up much less space too.

 

[peter anderson]

Why didn't it occur to me that there might already be an internal overflow? Good thinking Bas

 

[taydo]

let us no please if it is already internal overflow

Thanks

 

[llykstw]

No, there's no internal overflow at the moment - I tested it last night. It definitely leaks over the floor! I'll need to lower the cistern, because at present the top of the siphon fouls the lid of the toilet enclosure (so every time you slide the lid on or off to get at the cistern, it moves the siphon about). That means I'll need to:
1. Buy a new cistern
2. Buy a new (internal overflow) siphon
3. Buy a new flush pipe (but could possibly reuse the existing one, depending on its condition)
4. Fit together flush pipe (having cut to length), cistern, siphon and float valve (which I already have)
5. Attach cistern to the wall (using brass screws, rather than the manky rusted steel ones that were used in the existing assembly)
6. Drill a new hole in the cistern enclosure for the flush lever, and fill in the old one with mastic or similar
7. Re-route the inlet water pipe to match the new cistern level (and probably install an isolation valve as there isn't one currently).

Does this sound right? I think I've covered everything, except sealing the odd leak with a bit of silicone where necessary. Is it a good idea to fit a spring mechanism non-return valve somewhere on the inlet pipe, to reduce potential water hammer (seeing as I'm going to instal new pipework anyway).

Thanks for all your help everyone!

 

[Bas]

Sounds about right but why drill a new hole in thye cistern? If you use a torbeck valve you should ber able to use either lh or rh handles.

Regulations say you should fit a service valve anyway. Some flexible connectors have integral ones making the job easier and neater.

Good luck

 

[llykstw]

Sorry, I'm not being clear. The cistern is boxed into a cabinet - it's the cabinet that I'll need to drill a hole in, not the cistern itself