2 washing machines and dishwasher

[hammerheat]

I've got a customer who wants 2 washing machines and a dishwasher plumbed in on the same waste pipe. This is in a conservatory and a 40mm waste is currently doing 1 washing machine is it feasible to put the extra machines on? The waste pipe disappeares under the floor with no access to it, the total waste pipe length will be approximately 3m.

 

[oz-plumber]

Can't see it being a problem.

 

[sammathias]

I would say 2". pipe needed due to length. depends on how many bends there is in the pipe. if its pretty much straight you may get away with it when they are all draining at the same time

 

[ShaunCorbs]

Another vote for 2" as they could be used at the same time

 

[king of pipes]

2"minium ,3"would be even better . kop

 

[hammerheat]

I would say 2". pipe needed due to length. depends on how many bends there is in the pipe. if its pretty much straight you may get away with it when they are all draining at the same time

40mm pipe disappears under the floor no access to it

 

[snowhead]

Providing the existing is sound all the way and not crushed or with lots of elbows in it.
It's unlikely that any 2 let alone 3 will be discharging water at the same time.

The 3 in total would be less than a bath.

 

[king of pipes]

Dont think i would do that it wont be to long before it blocks then of course it will be the plumbers fault on you head bud . kop

 

[sammathias]

Providing the existing is sound all the way and not crushed or with lots of elbows in it.
It's unlikely that any 2 let alone 3 will be discharging water at the same time.

The 3 in total would be less than a bath.

agree with KOP....if a bath waste was blocked it would just drain really slowly. but if the waste in question was blocked then the machines would have nowhere to pump so water would be forced backwards out of the stand pipes.

 

[oz-plumber]

40mm pipe disappears under the floor no access to it

With all the negative scenarios regarding bends and crushed pipes, they are out of your control.
The situation you have is a 40mm pipe that is unaccessible and has a run of 3 metres.
I would have hazard a guess that even if all 3 appliances discharged their wastes at the same time the pipe, if installed correctly, would handle the load.

As for blockages, most are caused by pipework not installed correctly and not enough waste flow through pipe.

You have a couple of options.
- Have the drain cameraed prior to starting works, at a cost to the customer.
- Or do the works requested with a clause in your quote regarding connecting to existing drains.