Solar Heated Water for Washing Machines with a Cold Feed only.

[ecogeorge]

What about this ? 
Hot and cold feeds with seperate solenoids  and temp mixer valve set to reqd temp (reclaimed  washing machine/dishwasher fill valves) .
A delay timer.
Connect  washing machine water inlet (original) to delay timer so that once a signal is received hot valve opens and NC RELAY connected to cold feed opens preventing cold fill.
Set delay timer for say 10 mins operation to fill machine.
After 10 mins machine would revert to cold fill only (rinses). This would only happen if timer was set to not repeat for say 1 hr (length of complete wash cycle). I believe there are timers that will do this ? or have I got too far down this bottle?
rgds George.

[Greenbeast]

Paul, i had already decided to TMV ALL hot water coming from the tank as i do intend to let it reach 80-90 degrees (more energy stored obviously)
I had decided on 45degrees but with our current system the water is sometimes more than that anyway, so i've revised it to 50 degrees.

I'm having trouble finding a 3 port diverter valve (non mid-postion), i managed to get 1 on ebay last week for my heat dump but everything else appears to be mid-position

My new concern is...Will a standard honeywell (or equivalent) 3 port valve, spring closed against mains pressure cold? Can i reduce the pressure some how?
I don't have a low pressure cold feed near the machine and i'm trying to avoid running more pipe into the kitchen at the current time

There will be approximately 2.5-3m of 15mm pipework between my cylinder and W/M, that should contain 0.5 litres of cold water (after standing some time)
So my options would be to:
1 auto-drain it, extra money work for little gain
2 prime the pipe by running kitchen tap, easy to do, we only run 3 washes a week, so no major hassle
3 not bother, i don't know the total quantity of water the machine takes in to wash, so i don't know how 0.5l of cold will affect the overall temp

[Greenbeast]

Looking at the documentation for the honeywell 3 port diverter valve, it says maximum differential pressure is between 0.5 and 1.4 bar (depending on exact model)
If the mains is at 3 bar (i don't know) then that puts a standard valve out of the question unless i can reduce the pressure

[lightfoot]

Here's a low-tech solution...http://www.carbolicsoap.com/bwashboards-c-235.html ...but you may end up washing your own socks

[Amy]

Looking at the documentation for the honeywell 3 port diverter valve, it says maximum differential pressure is between 0.5 and 1.4 bar (depending on exact model)
If the mains is at 3 bar (i don't know) then that puts a standard valve out of the question unless i can reduce the pressure

It has to be a frosty day in hell before you see mains pressure at 3 bar these days.

Since the OFFWAT ombudsman kicked ass over water leaks and punishing the water utilities for giving shareholders a fat dividend rather that fix the leaks, the companies have reduced the pressure as a way of reducing leaks.

Some days, maybe washday, or car wash day, when there is excessive use, the pressure can be as low as 1.75 bar

[Greenbeast]

lightfoot - lol, thanks, think i'll keep working on the current solution

amy - Well even so i can't guarantee the difference will be low enough, my gravity pressure should be around 0.6 bar (i think), so i think i'll be looking at a pressure reducing valve to take the mains to close to 1 bar

[David]

Static water pressure, as measured by a gauge, in my house is between 4.5 and 5 bar usually. The two things it feeds directly, shower and kitchen appliances, have pressure regulating valves.

Scottish Water is a Quango rather than a company and I have never seen anything about OFFWAT here, which may explain the difference.

Perhaps I should have fitted a permanent gauge when I was working on the water, in order to keep an eye on whether they are reducing the pressure.

[Greenbeast]

can i not just fit a gate valve and have it partially closed to restrict the mains pressure?
or am i being stupid?

[Amy]

To a point, you wont restrict the pressure, just the flow, untill of course the flow becomes so diminished the pressure also reduces

[Greenbeast]

Amy, in your opinion, is that an avenue worth investigating, a gate valve and pressure gauge maybe or should i just stump up for a PRV?

[Mike McMillan]

My Indesit WG1130T, which has hot and cold inputs has been running off the hot water tank for the last 6 years. The element is disconnected (as we are off grid) and it has a manual temperature control. As long as this is set below the tank temperature, it works fine. 50 degrees in the tank translates to 40 degrees in the machine. I have obviously got to keep her running until you guys have designed a fix...

[Amy]

Amy, in your opinion, is that an avenue worth investigating, a gate valve and pressure gauge maybe or should i just stump up for a PRV?

Do a PRV cos it will then deliver the same pressure through all eventualities and fully protect other appliances and not restrict flow

[wookey]

Paul - at least you got a technically cogent response - that's quite an acheivement.

I don't see how his argument that damage must be prevented sits with the fact they used to take in hot water with no control over the temp of that. If it used to be possible then it is still possible.

he points out the issue of run-off water wastage, but fails to weigh that against the energy cost of water heating. My gut tells me that heating the water (electrically) is a much larger cost (both financially and environmentally) than running off the cold water in the pipe (couple of litres?), but we should do the sums in order to have the numbers to hand for this sort of argument (which will keep hapenning until a solution arrives.

He is right to say that this is really a systems problem. The washing machine optimum behaviour depends on both the plumbing type/arrangement it is attached to and the sort of detergent used. The rising-temp profile of the detergents is perhaps the most problematic issue. Either that needs to be abandonned or we need to work out some way of doing that with external hot-water supply.

Clearly a whole system analysis is needed. Energies of solar hot water, electrical hot water, cold water, detergent profiles, waste water systems. And he's right that the home automation protocol miasma doesn't help. (The HA system could provide the 'system smarts' needed to tell the washing machine how to behave, or what it was attached to, but we are nowhere near that sort of thing yet).

I guess there is a whole PhD in this lot. In the meantime we need to add a simple 'heater nobbler' switch, and maybe an aftermarket valve which can be set to provide hot/cold at appropriate times (see discussion passim) is the best way to make this accessible to the solar masses.

[Greenbeast]

Amy, in your opinion, is that an avenue worth investigating, a gate valve and pressure gauge maybe or should i just stump up for a PRV?

Do a PRV cos it will then deliver the same pressure through all eventualities and fully protect other appliances and not restrict flow

thanks

[Ivan]

Now we've got copious amounts of hot water in the cylinder most of the time, I'm going to try the washing machine filled entirely from the hot fill, and see what happens. Does anyone know what quantity of water a modern washing machine uses for rinsing? ie If I save myself say 0.4kWh per cycle, what amount of hot water am I using unnecessarily for rinses?