To trap or not to trap - Shower waste

[Arducius]

I have some questions about showers, particularly the waste: Do I need to include a "normal" trap as part of the shower waste? I've been doing some searching and have seen people advocating both using one and not bothering.

 

My instinct is that it's not required as we won't be connected to a drain and therefore there will be no smells to rise up through the plug hole. Also as the water is being flushed through fairly regularly (this will be a liveaboard) there isn't much time for what little water doesn't get pumped out and is left in the pipe to stagnate and become too smelly.

 

I ask because we are not planning to have a shower tray, but instead have a wet room setup with a shallow slope on the floor in the shower area to aid drainage. Therefore this area of floor will be lower than the rest of the bathroom and I'm trying to figure out how much space to allow under the floor for the waste pipe and fittings.

 

I understand that with a Whale Gulper pump the pump can sit above the lowest point and will still happily raise the water up to a skin fitting so currently the plan is that this would be located in a cupboard behind the bulkhead.

 

Would I be able to install a "normal" plug hole (sink waste) like this one, and then a right angled bend, and then the waste pipe leading from that off to the pump?

 

Thanks in advance and please excuse my ignorance, plumbing is something I have very little experience with (so far).

Edited July 8, 2013 by Arducius

[davidb]

Hi, that all sounds like a good plan to me, I used to have little grey water tanks, but you are better off without them. My latest modification is to trigger the gulper relay with a water flow switch in the hot water flow to the shower mixer, so you don't need a manual switch in the bathroom. Its working well.

 

cheers, David

[nicknorman]

You don't need a seperate trap, probably you will end up with the pipe dipping down from the plughole and then rising again, so water will tend to collect at the lowpoint of the pipe, acting as a trap. The advantage of having some sort of trap is that it stops a howling gale blowing into the shower on a windy day!

[Neil2]

I can't see the point of a "U" bend on a boat but I've just read a survey report on a boat that strongly recommends the fitting of swan neck bends at high level to prevent back flooding. I've never seen an inland waterways boat with such an arrangement but clearly this surveyor thought there was a risk. I suppose some boats do have outlets close to the waterline but it seems a bit over the top to me. They'll be having us fit sea cocks next.

 

It's a good idea to have the length of level waste pipe long enough to contain the amount of waste water that doesn't get pumped overboard. My last boat didn't and that's how you get that annoying pool of water permanently in the shower tray.

[pete.i]

I think also with a trap and it is a trap ie it will trap stuff that goes down it and eventually block up especially those daft little low profile traps used for baths and showers, it needs to be reasonably accessable so that it can be unblocked. My shower just has a pipe to a whale that sucks that water out to a skin fitting. everything is reasonably accessable and more importantly easily unblockable.

 

Pete

[Arducius]

Firstly, thanks for all your replies! Very helpful indeed.

 

Hi, that all sounds like a good plan to me, I used to have little grey water tanks, but you are better off without them. My latest modification is to trigger the gulper relay with a water flow switch in the hot water flow to the shower mixer, so you don't need a manual switch in the bathroom. Its working well.

 

cheers, David

 

That sounds like a very good plan, I might have to steal that idea. Although I think I'd include a manual override switch just in case!

 

You don't need a seperate trap, probably you will end up with the pipe dipping down from the plughole and then rising again, so water will tend to collect at the lowpoint of the pipe, acting as a trap. The advantage of having some sort of trap is that it stops a howling gale blowing into the shower on a windy day!

 

Ah yes of course, that hadn't occurred to me but now you mention it seems blindingly obvious.

 

I can't see the point of a "U" bend on a boat but I've just read a survey report on a boat that strongly recommends the fitting of swan neck bends at high level to prevent back flooding. I've never seen an inland waterways boat with such an arrangement but clearly this surveyor thought there was a risk. I suppose some boats do have outlets close to the waterline but it seems a bit over the top to me. They'll be having us fit sea cocks next.

 

It's a good idea to have the length of level waste pipe long enough to contain the amount of waste water that doesn't get pumped overboard. My last boat didn't and that's how you get that annoying pool of water permanently in the shower tray.

 

Hmm, I was of the understanding that so long as your outlet was 10" above the waterline then all was hunky dory. And yes, I'm already planning to have a good length of waste pipe between the pump and shower to stop puddles forming (thanks to the narrowboat builders book for that one).

 

I think also with a trap and it is a trap ie it will trap stuff that goes down it and eventually block up especially those daft little low profile traps used for baths and showers, it needs to be reasonably accessable so that it can be unblocked. My shower just has a pipe to a whale that sucks that water out to a skin fitting. everything is reasonably accessable and more importantly easily unblockable.

 

Pete

 

That's something else I hadn't thought of, though I am planning to make everything as accessible as it can be when it's under the floor.

[Guest]

Hi, that all sounds like a good plan to me, I used to have little grey water tanks, but you are better off without them. My latest modification is to trigger the gulper relay with a water flow switch in the hot water flow to the shower mixer, so you don't need a manual switch in the bathroom. Its working well.

 

cheers, David

Agreed. Those little tanks are stupid; get a Gulper The relay water flow switch idea is neat

I didn't use a trap on the shower\bath drain, and have never noticed a draught up the pipe, though can see it might be a possibility in some installations.

[nb Innisfree]

After some thought we decided tho go manual rather than an automatic switch. It's in the form of a pull cord on the ceiling in the shower booth, cork ball key fob on the end of the cord is easy to grip and find with eyes shut. Simple and being manual allows you to run it longer to thoroughly drain.

[Arducius]

Many months have passed since I started this thread and I still haven't gotten around to this job but it will be done soon as I'm running out of other distractions!

 

I think I have everything planned out. We have bought the shower & whale gulper, first fix plumbing is in place, going to find a water flow switch so the gulper runs when the shower is on (wired up with manual switch for running longer periods if required) but I have one more problem to solve...

 

How does the gulper connect to the waste pipe? The pump has 19mm hose tails so I can clamp a hose over those no problem, but I'm going to need an adapter from a normal waste pipe from the shower that will reduce down to the 19mm hose to go onto the pump. Does such an adapter exist?

[nicknorman]

Not sure what type of waste connection you mean, but perhaps something like this is appropriate?

 

http://www.midlandchandlers.co.uk/Catalogue/ProductDetail/waste-adaptor-1-1-2-to-3-4-1-hose?productID=4ae2c9f6-db3f-40a5-b09c-3bd6c2536403&catalogueLevelItemID=00000000-0000-0000-0000-000000000000

[Arducius]

That looks like exactly the sort of thing I need! Thank you.

[Sabcat]

You don't need a seperate trap, probably you will end up with the pipe dipping down from the plughole and then rising again, so water will tend to collect at the lowpoint of the pipe, acting as a trap. The advantage of having some sort of trap is that it stops a howling gale blowing into the shower on a windy day!

 

I think the pump will prevent a gale blowing into the shower, there's no trap on mine and I've never had a wind problem, not from the shower anyway. The gulper is fixed to the hull side lining about halfway (in terms of height) between the skin fitting and the shower waste.

[monkeyhanger]

Many months have passed since I started this thread and I still haven't gotten around to this job but it will be done soon as I'm running out of other distractions!

 

I think I have everything planned out. We have bought the shower & whale gulper, first fix plumbing is in place, going to find a water flow switch so the gulper runs when the shower is on (wired up with manual switch for running longer periods if required) but I have one more problem to solve...

 

How does the gulper connect to the waste pipe? The pump has 19mm hose tails so I can clamp a hose over those no problem, but I'm going to need an adapter from a normal waste pipe from the shower that will reduce down to the 19mm hose to go onto the pump. Does such an adapter exist?

I have fitted a filter in the line before my extraction pump. You'd be amazed at the amount of hair it traps. Don't know whether hair will pass through a gulper, but if it clogs I'm sure you can work out when it will happen Sod's law and all that.

[nicknorman]

I think the pump will prevent a gale blowing into the shower, there's no trap on mine and I've never had a wind problem, not from the shower anyway. The gulper is fixed to the hull side lining about halfway (in terms of height) between the skin fitting and the shower waste.

Blimey delayed reaction - I made that post 20 months ago! Anyway, I agree the pump should stop drafts (maybe depends on the type of pump, but a gulper certainly will) but for a sink / basin a trap is a good idea for the draft reason. I can't remember what was in my head 20 months ago ie whether I was thinking about a shower or a basin!

I have fitted a filter in the line before my extraction pump. You'd be amazed at the amount of hair it traps. Don't know whether hair will pass through a gulper, but if it clogs I'm sure you can work out when it will happen Sod's law and all that.

Better without a filter, all the gunge goes through the gulper. With a filter, it will need regular maintenance or it will block. Edited October 28, 2014 by nicknorman

[smileypete]

That looks like exactly the sort of thing I need! Thank you.

 

Also have a look on Ebay for a stepped hose tail, some have 40mm plain ends that'll go into a standard 40mm water waste compression fitting like a bath trap.

 

cheers, Pete.

~smpt~

[alan_fincher]

You don't need a seperate trap, probably you will end up with the pipe dipping down from the plughole and then rising again, so water will tend to collect at the lowpoint of the pipe, acting as a trap. The advantage of having some sort of trap is that it stops a howling gale blowing into the shower on a windy day!

 

 

Blimey delayed reaction - I made that post 20 months ago!

 

July 2013 ?

 

Have you been buying cheap calendars of of somebody in a pub?

[nicknorman]

July 2013 ?

 

Have you been buying cheap calendars of of somebody in a pub?

Yeabut everyone knows that 12 months plus 3 months = 20 months, innit!

 

 

 

 

 

Base 5 maths BTW.

Edited October 28, 2014 by nicknorman