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View Full Version : Running hotwater and cold water into one connection..















montiee
11th January 2008, 02:34 AM
Hmm not sure if the title makes sense but hopefully the explanation below will.

Soon I will take delivery of a frontloading washing machine. A nice bosch one. The trouble is this thing only takes in cold water and not hot (alot of new ones are heading inthis direction). It heats the water itself. Now I guess for most households this is fine but I have a solar hot water system so I think it's stupid for the machine to heat water electrically while it's being heated by the sun for me for free. Is there a fitting I can buy from bunnings which will allow me to merge the two taps I currently have (hot & cold) into one for connection to the frontloader?

The idea is that I'll open the taps up so that on average the combined temp is 30C and that will I think save me time & money heating water unecessarily for most of my washes.

Anyone done something similar?

Note I really don't care for an elegant single tap if it's going to cost me alot. This is in the laundry so I could care less. It can be a couple of hoses merging for all I care. I guess I could knock it up myself form plumbing parts but hope there is something at bunnings which is ready made..

wonderplumb
11th January 2008, 05:25 AM
More hassle than what its worth, you will end up having to use a tempering valve or a TMV, if youve spent good money on a fancy washing machine, whats a few cents each load to let it do its job????????????

montiee
11th January 2008, 05:38 AM
More hassle than what its worth, you will end up having to use a tempering valve or a TMV, if youve spent good money on a fancy washing machine, whats a few cents each load to let it do its job????????????

Nah. I don't want anything as elaborate as a temporing valve. I mean it's like getting in the shower. You set the hot water tap at a quater turn and the cold at 1/8 turn (random figures used :) ) and you get ~30C. I'm not interested in anything fancy that ensures I'm dead on whatever temperature. If I'm off a few degrees no big deal.

As for a few cents a load sure but it's also time it takes to heat it up to that point etc. I guess if I get "hot" water for free why should the machine waste electricity making it's own and spending the time doing so. I do have a hot water tap already there..

I guess I need to find a two into one connector and then some tubing and an connector for the washing machine hose to screw into.

SilentButDeadly
11th January 2008, 11:02 AM
Is there a fitting I can buy from bunnings which will allow me to merge the two taps I currently have (hot & cold) into one for connection to the frontloader?


Unlikely...be easier and cheaper to make something up from poly plumbing parts - 3/4" T piece, elbow, nipple, two hose nipples, two hose clamps and some pressure hose........and perhaps a non return valve on the hot water side.

But are you absolutely certain that the Bosch machine can't be told/programmed to not heat the water?

Given that we too are tossing up on a Bosch or Miele front loader over the new breed of top loader (eg F&P Aquasmart) we too might have to consider this option...

montiee
11th January 2008, 05:38 PM
But are you absolutely certain that the Bosch machine can't be told/programmed to not heat the water?


Yes the bosch can do a proper cold load I am led to believe. Alot can't. However I think you get a better wash if it's luke warm 30C-40C. I'll be experimenting when I get it. Might just do a proper cold load first and see how it goes. If it's adequate they I'll drop the merge idea and if not well..



Given that we too are tossing up on a Bosch or Miele front loader over the new breed of top loader (eg F&P Aquasmart) we too might have to consider this option...

Yes I'm not a fan of the F&P. Parents have owned them in tha past and the control panels suck ???? and are expensive to repair when they eventually brake. You need to replace the entire panel. After we did this the pump died. I'm giving F&P a miss.

I wasn't too impressed with the one (toploader) my parents have had. I was surprised when they returned with another one after the first one broke down after only a few years. I asked why buy another one and I got the excuse that they heard they had improved..yeh right..

Anyway you might have a better run than my parents did. I personally think they where nuts to buy another one.

wonderplumb
11th January 2008, 05:42 PM
Mate if you already have hot and cold water points there you could make up a breech with a valve between the two with some 3/4 chrome tube and chrome plated brass fittings, it'll look as ugly as a hatfull but will do the job.

Smurf
12th January 2008, 08:48 AM
Assuming your hot water is mains pressure, just running both hoses into a Y shaped piece attached to the back of the washing machine will do the job. You can get brass ones for garden use and this should fit assuming the machine has standard sized connections (same size as outdoor tap).

You will need to remember to turn off the hot tap after the initial fill for the wash though unless you also want a warm rinse.

As for warm versus cold washing, my clothes get quite dirty at work and I can confirm that washing in warm water with decent detergent (I use "Biozet") gets them VERY clean. Jeans I've worn to work and had covered in all sorts of mess would easily pass as "clean" by anyone after being washed that way. Cold water doesn't get the same standard of cleaning in my experience - the same clothes eventually get that dirty look even after washing.

If you use hot (not warm) water then oil etc comes straight out too. I've never really understood why some people are so worried about getting their clothes dirty. Then I realised that they're probably using shoddy detergent in cold water and that's the problem. Also I don't see the need for all those pre-wash sprays etc - same reason I assume.

Honorary Bloke
12th January 2008, 08:52 AM
Assuming your hot water is mains pressure, just running both hoses into a Y shaped piece attached to the back of the washing machine will do the job. You can get brass ones for garden use and this should fit assuming the machine has standard sized connections (same size as outdoor tap)..

:iagree: Just be sure to get a nice brass one and check periodically for drips. :)

Barry_White
12th January 2008, 09:35 AM
Why not use a bath mixer or tub mixer.

bricks
12th January 2008, 05:27 PM
This won't work all that well.

If you join the two taps, you will have a cross connection. Over time, the other taps in your house will all become the same temperature, you may suck hot water through into the cold or vice versa.


WonderPlumb- you should have picked this up bruz- what's going on?

wonderplumb
12th January 2008, 06:47 PM
Bugger me!! I forgot to mention a check valve on the hot side.....

Good stuff Bricks, well spotted bloke!

I still reckon let the machine heat the water, they use so much power as it is already a little more wouldnt hurt.

bricks
12th January 2008, 06:53 PM
Bugger me!! I forgot to mention a check valve on the hot side.....

Good stuff Bricks, well spotted bloke!

I still reckon let the machine heat the water, they use so much power as it is already a little more wouldnt hurt.


You'd need one on both sides.

Barry_White
12th January 2008, 08:28 PM
This won't work all that well.
If you join the two taps, you will have a cross connection. Over time, the other taps in your house will all become the same temperature, you may suck hot water through into the cold or vice versa.




I'm not a plumber but that sounds a bit of a furphy to me. Every house I have been in has either a shower or a bath or both as well as sinks and basins where the water mixes together with out check valves and the hot doesn't contaminate the rest of the taps in the house or vise versa with the cold when both are turned on together. Well at least not in my house. So plumbers of this forum educate me and tell me why you think it would happen in this case.

Skew ChiDAMN!!
12th January 2008, 08:38 PM
But you don't simply block the outlet once the bath is full, you turn off the taps.

A washing machine, on the other hand, doesn't leave the water running all the time; it operates a "third" tap to shut off the flow but it doesn't shut off the other two. This leaves your hot/cold lines connected and any pressure differential between the two lines will give you a flow from one to t'other.

If Montiee wanted to stand by the washing machine manually turning off the taps every time the w/m shut off the flow, then it wouldn't be a problem. Or if he fitted a couple of one-way valves...

I'm no plumber. But even I can see it ain't a good idea to cross-connect your hot & cold lines. :;

bricks
12th January 2008, 09:10 PM
Basically what he said.

I will point out that the tap washer may in some instances act as a stopper

If you have both taps turned on, and the two open ends are connected and that connection has an outlet Ie shower head or breacher then the water pressure will allow the water to escape.

It's harder for the water to go back into the hot/ cold tap than out of the open end of the shower/ spout.

If you have sealed the end then they will mix, just as if you have connected the pipes together without valves ( because the valves are doing nothing. )

wonderplumb
12th January 2008, 09:13 PM
Because when the machine shuts off, you still have hot and cold water mixing in the middle, typically your hot will have less pressure than the cold, therefore the cold can return through the hot side, and vice versa mixing the two to give you a lovely luke warm temerature through either tap. Then you get problems such as the potential for legionella, hot water heater craps itself because its working its guts out etc. etc. Bricks is spot on with needing a check valve on either side, its been a long day:doh:

bricks
12th January 2008, 09:15 PM
Try working in morgue all day, you know that 6th sense movie

Yeah "i see dead people" starts to affect your concentration after a while.:(

wonderplumb
13th January 2008, 06:36 AM
Im hearin ya, I done a job at sutherland hospital in the morgue, we had to replace an RPZ to an autopsy table and clear a blocked flushing floor waste, very unsettling, espaecially when you see them wheeling them out of the fridge! :oo: I get spooked by stuff like that, I dont even like pulling up next to a hearse at the lights. The bloke I was working with wanted me to take a photo of him lying on the table, with no clothes on!,:no:as if he was lying in state.

bricks
13th January 2008, 11:58 AM
That's kind of amusing,

My apprentice thought that'd be a good idea too ( the photo's), but i've got a big problem with no paying due respect to people. He wanted to take photo's of the dead guys aswell- no way buddy.

Ive been down there for a whole week now, i've taken to leaving a radio on all day coz the bodies make noises and it freaks me out- especially when the dropsaw trips the circuit breaker.:oo:

montiee
13th January 2008, 03:13 PM
Good point about the check valve. Wondering whether it's all worth the effort now..:~
I guess it depends how much it's going to cost me. The cost may be more than the saving in the end...

jedmanrocks
13th January 2008, 07:08 PM
The easiest way out is often the most simple. If hot water is free for you and you never run out, just hook up to the hot WM tap. The machine heats until it reaches a certain temp, therefore if its only heating water from 60c to 80c you wont use much power , as compared from 15c to 80c. However it will mean that youll be rincing in hot water. If the amount of HW u use isnt a prob and u like faded clothes, its all good.
PS the cross conection issue isnt really a problem if u use spring loaded jumper valves in the WM cocks. However if they have been 'pinched' to quieten them down it will be an issue.:U

Smurf
13th January 2008, 10:48 PM
But you don't simply block the outlet once the bath is full, you turn off the taps.

A washing machine, on the other hand, doesn't leave the water running all the time; it operates a "third" tap to shut off the flow but it doesn't shut off the other two. This leaves your hot/cold lines connected and any pressure differential between the two lines will give you a flow from one to t'other.

If Montiee wanted to stand by the washing machine manually turning off the taps every time the w/m shut off the flow, then it wouldn't be a problem. Or if he fitted a couple of one-way valves...

I'm no plumber. But even I can see it ain't a good idea to cross-connect your hot & cold lines. :;
You would normally rinse in cold water. So the hot tap would need to be turned off after the initial fill for the wash anyway with only the cold left on.

dan76
14th January 2008, 07:30 PM
off topic but i have also worked in a morgue, was doing test and tag on all the saws etc in the room and there was one bloke who was frozen and they couldnt dress him for the funeral so they had the door open and the tray half pulled out to thaw him a bit so they could put clothes on him.
this was in a small country town hospital.
freaked me out a bit

jedmanrocks
14th January 2008, 08:03 PM
off topic again, but a funny tale. My Dad was a registered nurse until he retired. Years ago, when he was training in England, he tells the tale of one of the bodies that had been tagged and was meant to go to a teaching hospital for surgery training but got forgotten. My Dad and a friend fearing the abuse of their teacher, dressed the corpse in biker gear ( goggles and headgear as well ) and transported him themselves in a sidecar attached to my Dads friends motor bike.
Those were the days, imagine that happining now. Doubt it!

Markw
17th January 2008, 01:10 PM
We have a large Simpson F/L machine and with it you get selectable temperatures. If you want 40 deg water temp you just programme it in. The machine is plumbed only to the cold water and being a 5 star (or drip for water consumption whatever) you use bu99er all water and therefore use very little energy for water heating.

Montiee - don't be so miserable about the miniscule energy consumption for water heating - it only happens once on the wash cycle as all the other cycles are cold. Just plumb it up the way it should be - otherwise you have to change temperatures for the rinse cycles. If you dont or forget then your wasting your stored hot water and you'll end up using instantaneous energy to heat new in-coming water.