2 washing machines 1 drain

[Avi46]

Hi all,

The missus has managed to obtain another washing machine from her late aunt and has given me the task of plumbing both in. The soil stack currently has a toilet, small sink and 1 1/5 inch drain from the washing machine separately connected.

Would extending the 1 1/2 inch drain to an additional washing machine cope if both washing machines did actually drain at the same time? It is unlikely but I don't want to go into the garage one morning and find a big puddle!

Also is it worth adding another trap or would the single one do?

Would there be any advantage in making the stand pipes of the furthest machine slightly lower than the nearest machine to stop it back filling the other?

I am assuming 2 inch would easily cope, but it is a lot more work and if it isn't required I can save a lot of hassle and cost.

Thanks

 

[stef99]

I would assume a 2" pipe would cope, but I wouldn't bet on it.

tying into the soil pipe the same way as the previous way is best.

alternatively, can you not just connect it to the sink waste trap?

 

[Avi46]

Thanks for the reply stef.

It isnt something I initially considered to be fair but it could be an option connecting it to the sink waste trap, I will have a look into that.

Cheers

 

[Hugh Jaleak]

For peace of mind i'd put the second machine on it's own waste run. Chances of both draining together maybe unlikely, but in the event they did then I would be unsure one 40mm waste would cope. (Especially after a while when the pipe clogs up with soap, clothes fibres etc.) Only takes it to happen once to flood the place....

Sink trap could be changed (if necessary) to a trap with a spigot for a washing machine drain, provided this is a 40mm pipe. (If 32mm unlikely to cope with a washing machine draining.)

 

[Avi46]

Thanks Hugh,

Due to all the connections to the soil stack being taken and limited space to attach a boss or extend the stack, I am limited as regards putting in an additional run.

Regarding the sink trap method, I would need to change the trap to a one with a spigot if i went down that route but with the sink being a few meters away from the nearest washing machine and the sink trap aorund the same height as the top of the washing machine standpipe, I cant visualise how I could succesfully do it without there being rises in the pipe.

One possibility is to attach a 40mm boss to the sink waste pipe near the entry to the soil stack, and then have a normal run with trap and standpipe to the washing machine. I would have to change the sink waste pipe in this method also though, or at least have a reducer in line.

Can you pick any holes in that theory?

Cheers

 

[Hugh Jaleak]

The drain hose from the machines will need to be taken up to the height specified by the manufacturer to avoid the machine siphoning out during operation, so rises in the pipe have to allowed, however long horizontal runs of drain hose are best avoided to prevent stale water collecting and running back into the machine. Drain hoses must incorporate an air break at point of discharge into the waste to prevent any backflow into the machine from elsewhere. Achieved by either hooking into a standpipe or discharging above water level on an appliance trap.

McAlpine's V33WM allows two appliances to be connected to a single standpipe, but the worry still remains if a 40mm pipe could cope should both machines discharge simultaneously. If there is the option to run a 40mm from the stack, coupling in the existing sink waste as required, then that would be my preferred option. As long as the run from standpipe to stack in a minimum 40mm diameter, connection for sink (basin?) can be reduced to 32mm if required after the washing machine connection.

 

[Avi46]

Thanks for that Hugh.

I understand about the minimum hieghts of the stand pipe for the washing machine drain, although where the run goes there would be a low point after the trap which would create the scale water issue you refer to hence I dont think going to a spigot on the sink trap is a viable option.

I agree that adding a seperate 40mm to a T of the sink drain at 40mm then reduced to 32mm for the existing connection looks to be the best. Probably least hassle and cost too so thankyou for the info.

 

[Agile]

As its in a garage a leak would not be disastrous!

So I would accept two stand pipes connected to the same 40 mm drain.

Most unlikely to cause a problem unless the drain blocks.

But do you really need two WMCs and particularly to operate both at the same time?

A timeclock can be used to delay use until off peak time overnight.

Tony

 

[Avi46]

Hi Tony,

You are right a bit of a leak wouldnt be disastrous, but as I have to pipe it up and install some drainage system as the machines arent next to each other (I should of mentioned this earlier) I would rather do the works required within reason to reduce the risk.

I cant see the need two washing machines either but as it is a freebie and the other half is adament she wants them I have little choice.

The machines will be used out of sync with each other via the timeclock settings. But should something ever go wrong, it would be nice to prevent things in a worse case scenario.