Low Level Cistern - Connect Overflow to Flush Pipe


T

TheScullster

Hi all

As the subject really. Is there any reason why I shouldn't pipe an overflow
from the side of a cistern down and under said cistern and tee into flush
pipe?
If so, is there a reducing tee type fitting that would take 22mm overflow
pipe into the side of 38mm flush pipe?
The current overflow goes into a room soon to be a kitchen (hopefully).
I want to keep the existing cistern, box it in and fit a back to wall pan.
This way I have one toilet in the house that gives a decent flush volume
(unlike the flush three times 6Litre models currently on the market).


TIA

Phil
 
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S

Stuart B

Hi all

As the subject really. Is there any reason why I shouldn't pipe an overflow
from the side of a cistern down and under said cistern and tee into flush
pipe?
If so, is there a reducing tee type fitting that would take 22mm overflow
pipe into the side of 38mm flush pipe?
The current overflow goes into a room soon to be a kitchen (hopefully).
I want to keep the existing cistern, box it in and fit a back to wall pan.
This way I have one toilet in the house that gives a decent flush volume
(unlike the flush three times 6Litre models currently on the market).


TIA

Phil
So long as the flush pipe doesn't get blocked furth of the overflow
connection and the cistern doesn't overflow at the same time ...bit
unlikely I admit ...suppose it's the same with syphons with builtin
overflow arrangements ....did you consider changing to one of them ?
 
F

Franko

TheScullster said:
Hi all

As the subject really. Is there any reason why I shouldn't pipe an
overflow from the side of a cistern down and under said cistern and tee
into flush pipe?
If so, is there a reducing tee type fitting that would take 22mm overflow
pipe into the side of 38mm flush pipe?
The current overflow goes into a room soon to be a kitchen (hopefully).
I want to keep the existing cistern, box it in and fit a back to wall pan.
This way I have one toilet in the house that gives a decent flush volume
(unlike the flush three times 6Litre models currently on the market).


TIA

Phil
Call me a cowboy - but here goes ..................
When I fitted my cloakroom out a few years ago, the only option I had for
the overflow was to run it about 8 metres through my lounge.
I ended up drilling a hole in the top of the soil pipe and feeding the
overflow, incorporating a u-bend directly into this and sealing with
silicone - topping up the u-bend with water to create an air lock.
Afterwards I thought that the water in the u-bend would soon dry up and I
would forever be smelling the contents of the drain through the cistern but
we've never smelt anything and I've only topped the trap up once !
 
J

John Stumbles

When I fitted my cloakroom out a few years ago, the only option I had for
the overflow was to run it about 8 metres through my lounge.
I ended up drilling a hole in the top of the soil pipe and feeding the
overflow, incorporating a u-bend directly into this and sealing with
silicone - topping up the u-bend with water to create an air lock.
Afterwards I thought that the water in the u-bend would soon dry up and I
would forever be smelling the contents of the drain through the cistern but
we've never smelt anything and I've only topped the trap up once !
Maybe you've got an overflow that's keeping it topped up and because you
haven't fitted a tundish you can't see it!
Call me a cowboy - but here goes ..................
yeee - haaah!
 
J

John Stumbles

Hi all

As the subject really. Is there any reason why I shouldn't pipe an overflow
from the side of a cistern down and under said cistern and tee into flush
pipe?
If so, is there a reducing tee type fitting that would take 22mm overflow
pipe into the side of 38mm flush pipe?
The current overflow goes into a room soon to be a kitchen (hopefully).
I want to keep the existing cistern, box it in and fit a back to wall pan.
This way I have one toilet in the house that gives a decent flush volume
(unlike the flush three times 6Litre models currently on the market).
You can do it and IIRC BES have bits for doing so but it looks sh1t3
(unless it's all concealed). There are various alternative flush valves
with internal overflow you could use. If you have a standard size
syphon valve you can get 8" ones which are usually low enough to overflow
internally, or there are flap valves (which can use a regular-looking
handle) or push-button valves (many dual-flush) from Multiquick and Opella.
 
B

Bob Mannix

John Stumbles said:
You can do it and IIRC BES have bits for doing so but it looks sh1t3
(unless it's all concealed). There are various alternative flush valves
with internal overflow you could use. If you have a standard size
syphon valve you can get 8" ones which are usually low enough to overflow
internally, or there are flap valves (which can use a regular-looking
handle) or push-button valves (many dual-flush) from Multiquick and
Opella.
Yes, it's much, much better to fit a new siphon with built in overflow. You
can go to the flush pipe but it should be via a tundish (where the pipe
ends, there's a gap and then more pipe with a flared top to catch the flow -
this gives the required air break) and it looks (as he says) sh1t. You can
get interna;l overflow siphons from B&Q (I think).
 
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A

adder1969

Yes, it's much, much better to fit a new siphon with built in overflow. You
can go to the flush pipe but it should be via a tundish (where the pipe
ends, there's a gap and then more pipe with a flared top to catch the flow -
this gives the required air break) and it looks (as he says) sh1t. You can
get interna;l overflow siphons from B&Q (I think).

--
As I udnerstand it, and I could be wrong, there's no requirement for a
visible tundish as one would be able to see the overflow flowing into
the pan. That's why the european style flappers are now allowed.
 
B

Bob Mannix

adder1969 said:
As I udnerstand it, and I could be wrong, there's no requirement for a
visible tundish as one would be able to see the overflow flowing into
the pan. That's why the european style flappers are now allowed.
It *may* be the case that the regs have changed and the tundish is not
required (don't know) but it wasn't so you could see an overflow, it was to
provide an air break between the pan and the cistern.
[/QUOTE]
 
T

TheScullster

There certainly used to be. It clamped onto the flush pipe with some
bolts and had a side connection for the overflow.

Alternatively, as has already been suggested, replace the siphon
with one with an internal overflow.
The syphons I've seen with internal overflow provision, do so with a very
small hole.
These look like they would only accomodate a slight weep of the float
valve - anything worse hitting the floor!
Are there syphons out there that can cope with overflow from a serious valve
failure?
The feed to my cistern is low pressure.

Thanks

Phil
 
B

Bob Mannix

TheScullster said:
The syphons I've seen with internal overflow provision, do so with a very
small hole.
These look like they would only accomodate a slight weep of the float
valve - anything worse hitting the floor!
Are there syphons out there that can cope with overflow from a serious
valve failure?
The feed to my cistern is low pressure.
The very small hole is to allow air to escape so the siphon fills (otherwise
it wouldn't). Once full it flushes the toilet, the small hole not being
enough to break the siphon. This empties the cistern as per normal and the
cycle repeats. It should thus be able to deal with at least a cictern
filling permanently at its normal full rate.
 
S

Stuart B

The very small hole is to allow air to escape so the siphon fills (otherwise
it wouldn't). Once full it flushes the toilet, the small hole not being
enough to break the siphon. This empties the cistern as per normal and the
cycle repeats. It should thus be able to deal with at least a cictern
filling permanently at its normal full rate.
Unless the waste pipe blocks at the same time in which case you are in
the S*** ....That was the advantage of seperate overflows to outside
....Unlikely I agree tho'
 
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S

Stuart B

On Wed, 07 Mar 2007 11:00:15 +0000 someone who may be Stuart B


However, a dripping warning pipe in winter can slowly freeze solid,
with predictable results, so it is a matter of swings and
roundabouts.
Freezing winters ..Nah..That was years ago .haven't you heard of
global warming ..lol?
 

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