Are traps always necessary?

[saladdays]

Hello All,

I’m in the process of removing a sink from a utility room and replacing the worktop. The sink has a trap with waste water from the washing machine going into it. Downstream from the trap is the internal boiler drain pipe. The 40mm waste pipe then goes outside and into a gulley grid.

My wife wants the trap removed to increase cupboard space. Is it necessary to have a trap when there is no sink?

Thanks.

 

[ljrgas]

delete

 

[Hugh Jaleak]

Traps provide a water seal to minimise odours from the discharge pipework and the outside gulley, maybe not so noticeable this time of year but can really hum come warmer weather. If you want to maximise cupboard space, look at either fitting a washing machine trap or a HepVo waste valve, with a standpipe in a corner of the cupboard.

 

[saladdays]

Hugh Jaleak,

Are you saying that the outside drain smell would come through the boiler or washing machine?!

 

[Dan Robinson]

Yes

 

[Hugh Jaleak]

Not from the boiler or washing machines themselves, but depending on how they are connected to the existing waste could lead to odour issues. How are they currently connected?

 

[saladdays]

In the utility room the washing machine, boiler waste water and sink share a 40mm pipe.

There's another separate 40mm pipe which has a dish washer and sink on it.

The two 40mm pipes meet each other outside on the gulley grid.

Thanks for you quick responses.

 

[Hugh Jaleak]

How are the boiler and washing machine currently connected to the waste pipe before it goes outside to the gulley?

 

[saladdays]

The washing machine is attached like this:

http://www.screwfix.com/p/telescopic-appliance-trap-40mm/91793

The boiler waste pipe is on the output of the trap:

http://www.screwfix.com/p/washing-machine-drain-out-kit/75883?_requestid=1174709

 

[Whitespirit66]

Yes, take the sink trap out by all means, but there must be a trap between the gully and the washing machine/boiler condensate. You could use a running trap on the pipe after it enters the building. The boiler condense and wash machine stand pipe would then be after/upstream of the trap. This is one way, there are other ways of doing it.

http://www.toolstation.com/shop/Plumbing/Traps+Waste/Running+Trap+76mm+Seal+40mm/d20/sd2907/p63996