M17 MCHF Decon Unit...DON'T DO WHAT I JUST DID!

Ok...so to continue the soap opera of my M17....DON'T DO THIS....(unless you want your neighbors to come by asking what was that explosion I heard?)

If you have read my other posts you will know as of yesterday my M17 was running but not heating the water. I did some digging in the Technical Manual and started looking around. I found a couple loose wires, fixed that and waa-laa, I had fuel going to the burner. Put everything back together, fired it up, and NO HOT WATER.

So I'm not sure if this was my fault but I'm gonna say it quite possibly was...

I noticed that the water pressure was kind of high so I turned the pressure of the garden hose down. (I adapted the water inlet to accept a garden hose since I don't have a lake, large puddle, or water tank to siphon water out of) The burner kicked in, smoked like house fire, and the water started to heat up! YAAAAAAAY! So I walked over to my boat and started to see what this bad boy would do. About 2 minutes in to glorious hot water/steam the wand started to just blow a lot of hot air, no water, not a lot of steam. I looked back at the decon unit to see a little water coming out of the pressure relief tube. I went over to the front of the machine and saw the water pressure gauge PEGGED. The numbers stop at 230psi, my guess was it was a lot more. Then BOOM! Water pressure dropped to about 30psi and stopped coming out of the overflow. I shut the motor down. I noticed water coming out of the the burner where the injectors go into it. I then explained to my neighbor the neighborhood was ok and we weren't under attack.

I pulled the water coil out of the burner and found a massive tear/hole in the copper tubing. I don't know why that would happen since the pressure relief valve was apparently working. I'm not sure if it was from too much water being fed into the unit or too little water being fed into the unit. I'm leaning towards not enough water. I don't think that water pump is capable of pushing enough to do that. I think there wasn't enough volume of water since I went from the 1.5" (or so) inlet hose down to a 5/8 garden hose. Then what lower volume of water was there was too quickly turned into steam, built too much pressure and Ka-Blam.

Either way it looks like I have a 2 stroke diesel motor to put on a go kart and a lot of extra parts.

So, if you modify your unit to accept a garden hose I wouldn't walk away from it until all the gauges stabilize and you can see you're not building too much pressure.

No children or animals were hurt, no major property damage. . . .

I expect you could repair that. I do not know exactly what your machine looks like but it sounds like a Hotsy type hot water/steam cleaner machine. I have two of the American Kleaner MX-1 hot water/steam cleaners. They are very tricky to make work right with all of the interlocks but that is mostly good since you can build up some serious temps and pressures. You have to learn to read the stream out of the wand. When it starts to spit (hot water mode) it is time to check the temp. It should get no hotter than 225 degrees F but I have seen 500 as I am running for the blowdown valve!

Robert

FMJ said:

No children or animals were hurt, no major property damage. . . .

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Nope, not this time.

I am going to try and repair it. It's pretty thick copper tubing. Lucky for me it blew the hole about 5 feet from the outlet port. My plan is to cut one of rings out of the coil and braze the 2 ends together, trying to keep the outlet in the same spot. We'll see...

I have 2 of these units and I beleive both have 8hp 2 cycle engines and the TM shows a oil gas mix feeding both the engine and burner. Other units I rented use kerosene for the burner. Gas kind of worries me. I didn't get any documentation or hoses, wands, anything with them. When I bought them GL said they were missing the bladder tank, not everything else. I have regular pressure washers and I bought these to provide hot water to remove wax from my truck so I can paint it. I also have a neighbor that cleans drums and thought I could rent it to him to pay for it

It would be very nice to know what connectors are needed, the size of the pressure hoses and wands. Any help would be appreciated

Yep too little water flow, when steam started to come out of the wand it was the first clue something was haywire. These are a hot water low pressure washer and water supply for showers not a steam cleaner as you now know. Glad you are OK and damage was local to the heating coil.

When you use a hose you have to purge all the air out of it
before you connect it to devices like this or you get a little water
then alls you get is AIR then water comes and superheated steam
happens and things can go boom...

Hard Head said:

I have 2 of these units and I beleive both have 8hp 2 cycle engines and the TM shows a oil gas mix feeding both the engine and burner. Other units I rented use kerosene for the burner. Gas kind of worries me. I didn't get any documentation or hoses, wands, anything with them. When I bought them GL said they were missing the bladder tank, not everything else. I have regular pressure washers and I bought these to provide hot water to remove wax from my truck so I can paint it. I also have a neighbor that cleans drums and thought I could rent it to him to pay for it It would be very nice to know what connectors are needed, the size of the pressure hoses and wands. Any help would be appreciated

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I will see if I can find specs on the hoses and wands. The hoses are huge and overkill if you ask me...but what do I know? I just blew mine up! The cam lock connectors could be tough to match up. Might be better to purchase a matching male and female fitting and swap out the ones on your units (cam locks have different profiles...some may be the same diameter but don't seal properly with different manufacturers)

I bought one of these units a month or so ago & just stored it for later usage. The unit came with the power end & a big green metal footlocker full of 2" hoses w/ camlock fittings, 4 wands w/ quick detach fittings, a shower unit & a pile of replacement parts all still in the bags. There was a parts list, but no instructions. After reading this last attempt @ using the unit, it will stay in the container a bit longer. The 1500 gallon water bladder is a must to keep plenty of water flowing into the pump. A standard pressure washer will suck water out of a drum or your water supply; not needing pressure to make it work properly. I beleive you choked the unit for water volume & the resulting heater turned the water to steam too quickly & exploded your coil In my humble opinion.

Glad there was no damage to life or your property, just your pride & the newly damaged decon unit.

I just got my m17 working. I fill a 40 gal drum of water and keep the garden hose in it running. Check it often. I did not get the power I anticipated. Everything working well, kerosene in both fuel tanks but would not make the power to clean down a greasy motor. At 700,000 BTU's I would have expected more. Has anyone done big cleaning jobs? Also Office Depot will print out the 130 page manual in spiral back for $17.50. The 300 plus maintenance manual in two spiral bound manuals was around $49.00. So easy to use..Just bring them the CD.

FloridaAKM said:

I bought one of these units a month or so ago & just stored it for later usage. The unit came with the power end & a big green metal footlocker full of 2" hoses w/ camlock fittings, 4 wands w/ quick detach fittings, a shower unit & a pile of replacement parts all still in the bags. There was a parts list, but no instructions. After reading this last attempt @ using the unit, it will stay in the container a bit longer. The 1500 gallon water bladder is a must to keep plenty of water flowing into the pump. A standard pressure washer will suck water out of a drum or your water supply; not needing pressure to make it work properly. I beleive you choked the unit for water volume & the resulting heater turned the water to steam too quickly & exploded your coil In my humble opinion.

Glad there was no damage to life or your property, just your pride & the newly damaged decon unit.

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Yes, I agree with you on the choking part. 5/8 garden hose lacks the volume of water and too much water pressure shuts the burner down. (that was why I was having trouble getting the burner to fire up in the first place. When I turned the pressure in the hose down the burner fired up, then QUICKLY turned what little volume of water into steam) Within the next few days I will repair the copper coil and change the "garden hose" modification back to stock. I will find a suitable water container to connect the stock factory hose to the bottom and run my garden hose to the top of the container with a float shut off. The container will stay full and the beast should get enough to drink. PLUS I won't leave the control panel until all gauges level off!!!!!!!!!!!!!!!

Good luck with your repairs & susequent retesting. It sounds like you are on your way to getting it back together & running. A plastic 55 gallon water barrel with a male (or female, if you like) camlock 6" off the bottom that would connect straight to the intake of the water input connection of the unit would probably give you the right water volume, without the excess pressure problem you had last time. A float shutoff would prevent overflow of the barrel & wasting water. I don't think you can get over 250 psi with the unit running properly so how well it will work for our intended purposes is questionable. The prior poster had his running correctly he stated & it didn't perform that greatly as far as power is concerned. More testing by a few of us will help the overall cause!

I have 250 and 300 gallon plastic tanks which I might be able to use for this machine. Would any of you be willing to part with a cam lock hose and wand set? I was intending on using the unit for cleaning mold from roofs and brick walls. My cold water power washer is not doing a good job at it and I was told a hotsey was what I needed. I also need hot water to remove wax from m 923A2 bed. I saw these machines and bought one to try. Needless to say the people in Jacksonville sold the bladder, tools, and M17's separately. They only said they didn't come with the bladder tank. Now I have 2 of them that I can either make a manifold and use my existing sprayers or just sell them and get a hotsey

looking for a spray wand for my unit...if anyone has a spare they want to offload please let me know...thx!