Problem,Water then steam...

S

Supreme P/W

New member
I need help trying to figure out what possible could be happening with my hot water rig.
It happen twice in the past, and need help.
I have a skid mounted RK-21 that put out 5 gal. per min.
While powerwashing with the burner on, everything was going fine for one hour. Then it started... What happens is the following, I rel. the trigger on the wand and when I pull the trigger again the pressure drops causing me to start asking whats happening.
I continue to check all of my water connections and confirm that are fine, I still have water to the unit.
I remove the tip on the wand thinking Its clogged, continue to pull the trigger and see that nothing is now coming out, I keep
pulling the trigger and the very hot steam starts flowing from the wand. I shut down the burner thinging the temp is out of coutrol. still pulling the trigger the steam runs course and water is then seen flowing from the wand.
The second time it happen everything was the same but prior to the steam flowing out blackish oiley water was comeing out, I continue to pull the trigger and it then stops and then came the steam and again the ran out and then the water started to flow out of the wand properly.

It seems to only happen when I am pulling water from the flow tank.

My thought is that the unit was being starved of water and the coil was hot causing the water to vaporize turning it to starm, and when I turn off the burner and continue pulling the trigger the water cools down the coil making everything go back to normal.

Any help with this would be a big help...
 
i started having the same problem yesterday,i think it is the unloader malfunctioning causing the burner to keep running,or it could be a malfunctioning thermostat and the temperature overlimit valve open up which might be the cause of no pressure.the black is the inside of the hose melting or rust from coil.

i am purely speculating but i would like to hear other opinions as well.
 
I have a RK-43 and have had the same problem. The thermostat I have is probably shot. I am going to try a new one. When I read the heading on this post I was positive you were talking about a Delco machine. I wonder why it does that. It doesn't happen to me all the time just once in awhile.
 
Barry,

I also had a similar problem.

Is there a chance that you are leaving the unit in bypass for longer than a few minutes? I am assuming that you have your bypass hose routed back to your tank.

If the burner is shutting off as it should the remaining water in the coil may be super heating and turning to steam. You could avoid this by turning the burner off and keeping the gun open without a nozzle in it. Pull you pick up line out of the soap while you are down though.

You could also just turn the burner off a few minutes before you need to stop. Once the coil is cooled down you could stay in bypass all day long if your bypass hose is routed to your tank.

You would be suprised at how fast the temperature in the coil rises once you release the trigger and flow through it stops..

I installed a thermometer on the outfeed end of the coil. If I need to be down for more than a few minutes, I just let it cool to down to 100 F before shutting the burner off. I also use the cool down procedure when completing jobs.

I think that if flow from the tank was a problem it would occour the whole time you were running not just when you stop and start.

Thisinfo is what I did and is only a guide. Please check your machine setup carefully.

Good luck!
 
1) This most common cause for this problem is a switch malfunctioning. A Flow switch, Pressure switch, or a Vacuum switch. If the burner stays on when you let go of the trigger, you just found the problem.

2) The other cause is air being pulled into the water stream. Usually thru the upstream soap injector, loose hose clamps, ect.

3) The other cause is low water volume caused by a Pop-Off valve set too low or installed in the wrong place. This will allow the water to be diverted somewhere other than the coils. The size tip will sometimes have some effect as well. A tip that is too small will higher your pressure, but it will also make your unloader bypass extra water, lowering the flow rate into the coils, raising the water temp. A faulty Unloader can also cause this problem, it will bypass extra water back to the pump instead of the coils. A pluged filter will cause this as well as junk in your float tank.

4) Pump packings or valves in the pump will cause low flow as well.
 
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Wizard, I have a question on the steam and unloader relating to the topic. I do hoods and have a ball valve before the gun. I have a 4.8 gal/min landa. When doing the hood, I cut back the ball valve to reduce pressure and volume in hot water mode. I also have a 110 gallon tank for bypass. Should I be worried about super heating the water or steam in the line because of this? Not quite sure how the system is actually functioning when I cut the the volume down in hot water mode. Thanx for any advice. Kinda worried it will get to hot and maybe melt line or something crazy?
 
If the ball valve is on the output of the coils you have nothing to worry about.
If it is before the coils (between the pump and coils) you do!
 
Does your machine have a flow or pressure sensing unloader? I have seen the o ring go out on the outlet valve on the pressure type, and instead of unloading, the system loads up to the set pressure on the unloader, acting like a regulator instead. If this happens, the pressure switch will continue to see pressure and your burner will stay lit even though the water is not flowing. Get it checked immediately! Steam can be extremely dangerous in a system not designed for steam.
 

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