Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

Jethro ) wibbled on Friday 21 January 2011 17:03:

Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

Yes - you will get a strong suction effect when the loo is flushed, if a
block of loopaper goes down (makes a most effective piston).

The trap you mentioned would be a good solution. It is likley the AAV
integral to that trap will be sufficeint to protect the other trap, but I
couldn't absolutely guarantee it. What's the seal depth on the other trap?

Another solution is to "roll your own" with a small AAV on a short vertical
tee'd off pipe - perhaps near to the washing machine standpipe so the AAV
could be put roughly as high as the top of the machine's standpipe thus
abive the waterline of the basin.

A further solution would be to use a HepVO on the basin which will take care
of everything.

Cheers

Tim

--
Tim Watts

On Jan 21, 5:03*pm, Jethro wrote:
Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

What an antisyphon trap does is let air into the pipework if a slight
vacuum shows up. So there's not much need for 2 of them on one pipe.

I like keeping the drains as separate as they already are, that way if
one ever blocks you do at least have the other.


NT

On Jan 21, 6:27*pm, Tabby wrote:
On Jan 21, 5:03*pm, Jethro wrote:





Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

What an antisyphon trap does is let air into the pipework if a slight
vacuum shows up. So there's not much need for 2 of them on one pipe.

(Hits head with hand) Duh !!!! Of course ...


I like keeping the drains as separate as they already are, that way if
one ever blocks you do at least have the other.

Well IMO the chances of the soil pipe blocking are much smaller than
the chances of the waste pipe getting blocked (or frozen). And
besides, the existing arrangement is aesthetically **** ... it comes
out one side of the house, and goes all the way along (under the patio
door) to the otherside ... a good 5m run.

"Jethro" wrote in message
...
On Jan 21, 6:27 pm, Tabby wrote:
On Jan 21, 5:03 pm, Jethro wrote:





Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

What an antisyphon trap does is let air into the pipework if a slight
vacuum shows up. So there's not much need for 2 of them on one pipe.

(Hits head with hand) Duh !!!! Of course ...


I like keeping the drains as separate as they already are, that way if
one ever blocks you do at least have the other.

Well IMO the chances of the soil pipe blocking are much smaller than
the chances of the waste pipe getting blocked (or frozen). And
besides, the existing arrangement is aesthetically **** ... it comes
out one side of the house, and goes all the way along (under the patio
door) to the otherside ... a good 5m run.

Just boss the waste pipes into the soil stack, you should have 3" seal traps
on
as the soil stack is vent to the atmosphere, there should be no problems
witht the traps
being pulled. No need for ati-vac traps.

On Jan 21, 5:03*pm, Jethro wrote:
Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

Firstly does your vertical pipe have an open end somewhere outside?
If so there is no problem.

If not you might get low pressure in your waste pipe or you might
not. There are two solutions.

Deep seal traps. These have a deeper water seal than usual. The air
can still be sucked through them but enough water remains to maintain
the water seal & you don't get smells. This is the tradtional way and
is cheap.

The new fangled way. An air valve lets air be sucked into the pie and
then closes.
These are a stupid price for what they are and can go wrong as they
have a moving part.

The link is just a trap that incorporates on e of these, I would say
in an ideal spot to get gummed up in a year or two.

Just get some deep seal traps and you'll be ok for a fraction of the
price. If you look round your builder's mercants you'll soon spot the
difference.

http://uk.ask.com/web?qsrc=1&o=0&l=d...l+trap&dm=ctry

On Jan 21, 5:03*pm, Jethro wrote:
Following the big freeze, and having a narrow escape with a frozen
waste pipe going to an outside drain, I want to re-plumb the pipe to
go down the toilet stack in the cloakroom it passes, on it's way out
the wall.

I know you can get 90degree pan connectors with a fitting to accept a
waste pipe - so that side is sorted. However I am worried about
siphonage, when the toilet is flushed.

A lot of googling (why are plumbing matters so off-grid ?) and a phone
call to a local plumbers merchants suggests an anti-siphon trap

http://www.mcalpineplumbing.com/silenttraps.asp

would do the job. The pipe run starts with the washing machine, and
goes about 6' before it's joined by the sink waste, and then will go
about 5' into the soil pipe.

Does this seem practical, sensible, and the correct way ? Presumably I
will need two (although the shop guy said one on the basin - the
washing machine wouldn't need one as it was so long ???????)

cheers guys.

For the washing machine you can buy a standpipe thingy that has a trap
on the bottom. Or there are traps that have a washing machine waste
connection into the side of them.
http://www.screwfix.com/prods/91793/...tes-and-Traps/
Telescopic-Appliance-Trap-40mm