# Hot water outside tap with thermostatic valve.



## Mike steele (Jul 14, 2007)

I've always fancied a hot washer, but couldn't justify the £1000+ price tag, so I gave this a go with excellent results for just under £100!

My pressure washer is a Nilfisk c-120 which has a maximum inlet temp of 40 degrees. So all that was needed was an outside tap that could be set at 40 degrees max. After some research I discovered something called a thermostatic mixing valve or TMV. This is essentially a thermostatic shower unit but not as pretty. These are normally pre set at 42 degrees, but can be adjusted up to around 65 if you wish. Ideally this should be ran off a combi boiler so as not to run out of hot water!
All you need do is T off your hot and cold water under your sink, into the hot and cold inlets of the valve and run the mixed water outlet through the wall to a outside tap.
I've tried to show it in the pics the best I can, but its a little cramped under my sink to say the least!



















The outside tap kit with the white flexi pipe you can see to the left of the pic was refitted to the cold water to retain a cold outside tap too! The cold water to the left, hot to the right and mixed water is in the centre running out through the wall.

Here's the outside.










Hot 40 degree tap left and cold on the right!










I foamed and rinsed my car at 40 degrees throughout the winter achieving a near touchless wash (95 percent clean) without the expense of a hot washer.
If your pressure washer can accept 60 degree inlet water all the better. All you need do to adjust the valve is pull off the cap that says DVS on it and turn the allen bolt toward the positive until 60 degrees is reached (just place a thermometer under the running water).
40 degrees and Bilt Hamber foam didn't seem to have any effect on my wax (Zymol titanium) however, I imagine 60 degrees on a regular basis would shorten the life a little.

So,all you need is a TMV ( approx £50 from a plumbing supplier), a outside tap, some T's, elbows, pipe and some very basic plumbing skills! 
I recommend using the brass hose connectors with hot water as the plastic Hozelock ones can pop off when they get warm especially if they're a bit worn!
I don't run the hot water all the way through the main hose, I just connect it to the pressure washer with a short length to prevent too much heat loss through the hose itself.

Sorry if I've rambled a little but this is my first proper post! Hope you can make sense of it!


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## liam99 (Dec 29, 2009)

Good write up. I was thinking about this the other day.


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## Guest (Mar 15, 2012)

Thanks for writing this up. I planning on doing something similar this year. I've had great success with hot water through the p/w too, but it was only a temporary affair.


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## BandyQuill (Jun 21, 2010)

i did something slightly different on mine, i hooked up a hot feed and a cold feed through a T piece, this was mainly just to fill buckets and the likes though, works really well


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## PaulN (Jan 17, 2008)

Great work there. Did you drill the tap mounting holes too big first time? lol


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## SteveyG (Apr 1, 2007)

No double check valve?


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## Mike steele (Jul 14, 2007)

PaulN said:


> Great work there. Did you drill the tap mounting holes too big first time? lol


Nah, that's where the original cold tap was!


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## kasman (Sep 10, 2009)

Good write up Mike, thx for the info, very useful:thumb:


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## Mike steele (Jul 14, 2007)

SteveyG said:


> No double check valve?


No, I didn't fit one. I figured it would reduce the flow a little. That, and there hasn't been one on my outside tap for the last 25 years! Thought I'd take a chance!


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## banditbarron (Sep 1, 2007)

Also be careful running PW off that cold connection as those kits only create a hole in the pipe about 5mm wide so check the flow rate from it if running an expensive PW. :thumb:

This is my setup


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## Mike steele (Jul 14, 2007)

banditbarron said:


> Also be careful running PW off that cold connection as those kits only create a hole in the pipe about 5mm wide so check the flow rate from it if running an expensive PW. :thumb:
> 
> This is my setup


Yeah, the cold set up is just temporary. i'm going to plumb it in with a isolating T and some copper pipe ready for summer. I've only been using the hot through the winter.
Yours looks good! How do you control the water temperature though?


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## macmaw (Mar 5, 2007)

I have a hot water tap outside too as i wanted to run my PW on hot water, but found that the hozelock hose gets sucked closed by the PW when hot water is going through it, I'm on the look out for some heat resistant hose that won't get sucked closed
Apart from that the hot tap is very handy for filling buckets too, means I don't have to go inside at all for anything


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## JJ_ (Oct 26, 2005)

That looks really good, does anyone run a shower outside ? An electric one ? Thinking of doing this maybe.


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## liam99 (Dec 29, 2009)

JJ_ said:


> That looks really good, does anyone run a shower outside ? An electric one ? Thinking of doing this maybe.


http://www.detailingworld.co.uk/forum/showthread.php?t=161718


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## Russ and his BM (Jan 1, 2008)

Similar results here, a near touchless wash.


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