Radiator Mist Cooling System

[DrivingMissLazy]

Mist Radiator Cooling System
I installed a mist cooling system on the radiator of my converted Eagle coach to resolve temporary overheating conditions, particularly when pulling long steep grades. I purchased the components at the local hardware store and total cost was probably less than $20.00. A Google search will give lots of ideas on this system.

The misters come in various ratings which are in Gallons per Hour I believe. Buy the misters that provide the MINIMUM water flow.

I used six misters total with two rows of three in each row. In addition to the misters you will need a few T connectors and some ¼ inch black tubing sold with the misters. I spaced the misters about 8 inches apart and the two rows about 12 inches apart. None of these dimensions are critical.

I used tye wraps to tie the tubing to a cross brace on the front of the radiator about two inches from the radiator coil. Use miniature tye wraps and also install them at each location where a T or mister is installed. The tubing tends to get hot and expands and the joints come apart. I used a tye wrap tensioning tool to pull them as tight as possible. Do not just plug the misters into the supply line. Use T connectors and short sections of hose. 

I connected the two ¼ inch runs together to a ½ inch section of tubing and run it forward to the fresh water tank area. I had previously installed a spare water pump as an emergency back up, so I just re-plumbed it slightly to feed the mister system instead of the coach. A remote switch with indicator light was installed on the dash to control the pump.

During testing I found that nothing was very critical about installation. I turned the misters so that they were pointing forward and about 120 degrees away from the radiator. This allowed the mist to disperse quite nicely outward and cover a larger area of the radiator. The engine should be running at a fast idle while making this adjustment.

As I have stated previously, the results of this system was simply amazing. Never again did I worry about outside temperatures or the size of the grade I had to climb. I never had to back off on the throttle or turn off my genset, which was plumbed thru the coach cooling system. I did try always to maintain a minimum of 1800 rpm while traveling the mountain passes.

I typically would wait until the coolant temperature reached about 200 degrees. And then turn on the mister. Within just a very few minutes the temperature would slowly start to drop and generally within 5-10 minutes it would be back at the 180 degree mark. At that time I knew that the complete cooling system was back down to 180 degrees or below, so I would turn it off and just continue monitoring the temperature.

I believe that I would have to use the system two or three times during the climb out of Death Valley on the way to Las Vegas. It really would not have mattered if I would have had to run it continuously as it consumed such a small amount of water. I could never detect any appreciable amount of water used while using this system.

It is definitely not a band aid system and I never saw any buildup of residue on the radiator during the 10+ years I used it. And I traveled well over 100,000 miles and made numerous trips thru the mountains where the use of it was required.

Sorry to be so long winded, but I so many persons have asked about this and I have made partial answers so many times that I decided to take the time and do it right for a change.
Richard

[Len Silva]

I once built a similar system around my air conditioner condenser at home.  It would spray water on the condenser whenever it ran.  It worked great and knocked the run amps down by about 40%.
The problem was that within a few months, the condenser was completely clogged up with calcium deposits.  My attempts to clean it with a mild acid (vinager) ruined the condenser.

I think that if I were to build such a system, I would have a dedicated tank with distilled water.

FWIW

Len

[El-Sonador]

I once built a similar system around my air conditioner condenser at home. It would spray water on the condenser whenever it ran. It worked great and knocked the run amps down by about 40%.
The problem was that within a few months, the condenser was completely clogged up with calcium deposits. My attempts to clean it with a mild acid (vinager) ruined the condenser.

I think that if I were to build such a system, I would have a dedicated tank with distilled water.

FWIW

Len

I was thinking the same thing Len.... May be a great added step in prevention and easy to incorporate and re-fill through the use of an old fire extinguisher, pressurized with air. - no pump needed
From what I have read here, the amount of water needed to mist the rads are very minimal and a fire extinguisher full may be enough for an average trip.

A good supply of Distilled water is always good to have on-board for Rad top-ups and battery top-ups anyways.

Does this make sense or not... Anyone...?

Steve

[Buffalo SpaceShip]

Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown
Longmont, CO
4106-1175
4108-216

[Len Silva]

Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown

Longmont, CO
4106-1175
4108-216

I have found that 24 vac coils and relays work well on 12 vdc without overheating.  Can't explain the theory, but it seems to work.

Len

[DrivingMissLazy]

Great post, Richard! As long as we can keep a certain BNO poster from finding this and telling you that the "sky is falling", you'll do a lot of good helping folks cool their engines in marginal conditions.

My only question is what valve/solenoid did you use to control the flow. I've checked into inexpensive sprinkler control valves at the local Big Box that would seem perfect... but they run off of 24VAC current instead of DC. I found Grainger valves, but they're expensive and seem like overkill for the kind of flow and psi we're needing.

My runs up I-70 and over the Divide would be a lot less stressful for me (and my mill) with this setup!

Thanks again, Richard!
Brian Brown
Longmont, CO
4106-1175
4108-216

Thanks Brian. I just turned the water pump on and off with a switch. The water pump was plumbed into the potable wter supply. The better/easier thing to do would be to use a solenoid off the existing potable water system. The thing is to find the prover 12 volt operating solenoid at a reasonable price.

Of course if you have an inverter running, then you could use a 120 volt solenoid. Come to think of it, I always had my genset running so I had 120 volts AC whether the inverter was on or not.
Richard

[dug]

I found a 12v solenoid for a sprinkler system at Home Depot.  I plan on using it.

HTH,

Dug
75 MC8
Arcadia, FL

[Buffalo SpaceShip]

Richard, I see... you just used a different water pump for the mister. That could work!

I was thinking of installing a 24VDC solenoid (on the coach side elec.) to just open a valve from the tank under the bed in the back and the existing water pump would supply pressure to the mister until the valve closes.

I could mine eBay and pick whatever unit is cheaper. Or just buy a Toro sprinkler valve, supply it with 24VDC and see if it fries it.

Doug:
Was the 12v solenoid in the sprinkler stuff? Have you tested it on 12VDC. Most of the valves I've seen call for 24VAC

Thanks guys!
Brian

[Gary LaBombard]

Richard, (Driving Misslazy)
Thanks for your support on this as I was going to do it no matter what after making my tank and all for my Eagle and by the looks of thing here on this post now I see that I was on the right track with the distilled water as well.  I have a dehumidifier that makes about 3 gallons a day, my tank is 29 gallons as explained on my web site.  I will be contacting you again after the framing is done here on my Eagle soon to get maybe a couple of photo's of your set up if possible.
I didn't believe I could be that far off in my thought of this.  Your success makes it worth while to put all the labor in making my tank.
Gary

[Hi yo silver]

OK, just in case any one needs a 24 volt d.c. solenoid, I have a supply of them, (Rainbird type), that will work just fine.  Can I say that on this board?  I won't post contact info in case I can't "advertise" them in this manner...
Dennis
HI YO SILVER! 

[Kent]

Great ideas.
Question; on a MC8 do I need two misters, one for each side, or just one?

Kent

[skihor]

I have a '67 MCI 5A w/ a 6v92 turbo and 5 speed auto. The rads are stock size and at sea leavel I have marginal cooling capabilities. Up here in the rockies it sucks. My rads have about 7000 btu capacity and the 6v92 can produce 12,000 btu. At temps over 75 I have to run the misters almost constantly. I hope to add two smaller rads to fix this issue. My first attempt failed, (due to their placement). Anyway I run 4 mist heads on each rad, spaced equally for full coverage. Each side is mounted to a pair of all-thread rods installed towards the outside of the rad compartments. I tried 1/2 gph heads but that isn't quite enough. I'm going to switch to 3/4 gph heads. They are hooked up to a sureflow pump w/ a lighted switch at the daash. no solenoids. The mist heads can be bought or ordered at any Ace hardware. I had trouble locating low flow heads. The original owner of my bus had two heads on each rad with 2.5 gph misters. I've had hot summer days where I used over 70 gal of water in one day. Also with that set up water would run out thus the change to smaller heads. Now with the 3/4 gph x 8= 6 gph total instead of 10 gph that I had.

[Barn Owl]

I knew a guy who used a windshield washer unit out of an old junk car. It was cheep, easy, 12 volt, had a built in reservoir, and took up little space so it was easy to mount. I thought that the capacity was on the small side, but he claimed that he used such a small amount of water that it never ran dry.

Laryn

[FloridaCliff]

I knew a guy who used a windshield washer unit out of an old junk car. Laryn

Now thats some Busnuts smarts.

Don't reinvent the wheel, just find a new use for it!

Cliff

[El-Sonador]

I knew a guy who used a windshield washer unit out of an old junk car. Laryn

Now thats some Busnuts smarts.

Don't reinvent the wheel, just find a new use for it!

Cliff

That made me think of those, like me, that are still on the Air wiper/washer system,
Could we just run a another line back to the rads off of the exsiting air washer system,
All the controls and wiring are up-front already.?

Steve