General drainage for airtightness

[EverHopefull]

You know how things come to mind at odd moments? I was shoveling snow off the drive this morning and suddenly I was thinking about the drainage from my planned heat pump tumble dryer going into the utility room. In general what route do the drains for anything like washing machine, tumble dryer and indeed sinks, showers etc take out of the building to ensure air-tightness?

I was thinking just tapping the drain of the tumble dryer into the washing machine waste but then got to thinking how does that waste get handed in such things as Passive house designs?

Back to shoveling snow again....

[Jeremy Harris]

We have a fair few bits of kit that need drains, the MVHR, water softener, condensing tumble drier and a couple of sealed systems that have low temperature pressure relief valves.  All drain into the main soil pipe stack, that runs under the passive slab.  There are water traps to stop any smells coming back up, just as you'd fit to a sink, basin etc.

 

To stop the internal soil pipe stack from acting as a cold chimney up through the house, it's capped with an AAV inside the roof space.  The foul drain is vented externally down at our treatment plant, to comply with the regs.

[Ed Davies]

23 minutes ago, JSHarris said:

There are water traps to stop any smells coming back up, just as you'd fit to a sink, basin etc.

 

Any problems with those drying out? Do you common any of them up to share a water trap?

[Gone West]

In our house I have a dedicated waste for the appliances in the utility room. The waste has a u-bend and exits into a 110mm soil pipe which goes down through the slab and insulation.

 

Edited February 1, 2019 by PeterStarck

[Jeremy Harris]

10 minutes ago, Ed Davies said:

 

Any problems with those drying out? Do you common any of them up to share a water trap?

 

I've connected the MVHR drains, PRV overflows and the softener drain to the same trap, down on the ground floor (all that kit is up on the first floor).  Having the trap downstairs in the utility room makes it easier to get at, and because the water softener will cycle every few days it keeps the trap topped up.  The condensing drier is connected to the utility room sink trap, which tends to get used enough to keep it full.

 

On the more general subject of traps drying out, as we very rarely use the bath in the second bathroom, we do find that the trap dries out.  We've just got into the habit of running the bath tap for a few seconds every few weeks.

[Pete]

1 hour ago, PeterStarck said:

In our house I have a dedicated waste for the appliances in the utility room. The waste has a u-bend and exits into a 110mm soil pipe which goes down through the slab and insulation.

 

Hi Peter, what is the thing at the top of the stack of unions please? ( The bit with the little hole in it!)

[Gone West]

@Pete It's a McAlpine V33WM vented twin waste connector.

 

https://mcalpineplumbing.com/traps/domestic-appliance-traps-accessories/v33wm-twin-connector