No suction from the venturi (no chemical into mixer tank)

No suction from the venturi (no chemical into mixer tank)

Been down to see the old machine today
Managed to get the pump in pump primed wired back up to the mixer tank and working fine at last with no leaks :hi:
Did not get the chance to fire the machine up and see if the pump in pump can keep up with the high pressure pump because I had a flat battery

One mineor problem is the pre heat exchange that had a leak that I soldered up before is still leaking

Other mega big problem is there is no suction or very little suction from the venturi
The venturi is located between the y filter and the mixer tank inlet
If you take the hose off of the back of the venturi you can notice a very very slight suction; no enough to suck chemical from a chemical jug
If I remove the 1/8 tail fitting from the venturi there is a lot more suction behind it; inside that 1/8 tail there looks to be some kind of black o ring and under that looks to be a spring and a ball Bering
Now I changed the tail fitting with another box standard 1/8 and sill hardly any suction from it

So this leads me to believe that the whole venturi is faulty or the pump in pump is not pumping faster enough but she seams to be ok
By the way the venturi is not I think the original venturi for the machine

Thanks

Batista

This did cross my mind but the battery was not dead dead! It just did not have enough charge to turn the start motor over and when I tried to turn the starter motor over I eminently went to my car to charge her up
I didn’t give it enough time for a full charge but when I took it off the car and put it back on the truckmount there was enough charge to turn the starter
However I did not bother starting the machine up as I had more pressing matters like testing the 1/8 box standard tail fitting in the venturi trying to see if it would suck chemical and obveslly it didn’t

But their was still a good amount of water coming from the supply pump at this time
Latter on I decided to try and start the machine up but there was not enough power there
I believe that a week battery can still power low amperage items likes lights and pumps to the wattage required but not have enough to power some thing heavy like a starter motor
But with the battery on charge over nigh this would sort that problem out

In the back of my mind I’m now wondering if the venturi is designed for high pressure suction and not low pressure suction
Like it being mounted after the HP pump oulets on a general pressure washer

spitfire 3.2; not sure what a float vale is but see my pix of my mixer tank in photo bucket

http://s291.photobucket.com/albums/ll319/Batista230/?action=view&current=mixertank.jpg

I think it is a box standard venturi; I will try relocating it today and let you know how I get on latter

Thanks

batista

Jeff did you mean this by siphon http://en.wikipedia.org/wiki/Siphon
I have tried to gravity feed the venturi and it has not worked the siphon effect failed

Jeff the solenoid valve is not present
Do you mean placing the venturi after the high pressure pump so it will have suction due to the high pressure passing through and what you meant by concentration increasing is the solution (chemical/water) being passed through the bypass exchange and passed through The entire system again and again adding more chemical each time

What is a float valve and float ball
I am imagining at the moment that the float ball is a mechanical device and not electrical; if so how would that operate an electric pump
I have been told that operating a pump on one float switch creates a rapid on off effect which will quickly burn out the pump dose a float ball not work on this principal

Been down to do some work on machine again managed to get it running and pump water with the pump in pump keeping up
But it seams when I put a heavy load on the machine at full revs like using the blower all she wants two is splutter and stall
Then the float switches keep doing things at first I just reset/disconect the wiring but then the upper float switch would not turn the pump off; if you raise the upper float switch to turn it off it would cut its power/noise by about half like it was half working
I then put my hand in the mixer tank and managed to snap the lug off the lower float switch and now it’s completely broke
I don’t know if its the wiring, float switches or relays at fault but without the float switches working the pump and mixer tank I may as well take a sledge hammer to the machine and then torch it and scrap it; which I probably will do if I have to spend any more time and money on it coz I just don’t see the point of wasting another tenner on a float switch

This is a long shot in the dark and if it works in theory then id probably be pissing in the wind in practice
But the shurflo pump I have is an on-demand pump and I think what they mean by that is let the pressure build up in the pump and hose and then run the trigger water come out and the pump switches on then you stop the trigger and the water stops and so dose the pump
Im probably contradicting myself hear when I harped on about operating a pump on one float switch and creating rapid on off effects
I remember from my window cleaning days of using water fed poles and using the most common of used pumps the ‘shurflo 60psi 3/8” bore (cant remember flow ratio) on demand pump'.
Mine was a home made trolley Wear the pump was simply wired up through a switch from live and to the pump to earth
I remember using those 45’ pole how the pump would stop start every second and at the top of the pole there was a continues flow of water; this was with out using a trigger though
I can say I had any problems with the pump
Imagine for one moment that there is no pre heat exchange (on a spitfire that’s the heat exchange that look like a mini car radiator which the pump in pump passes water through to the mixer tank)
And I was to plumb up the pump in pump directly to the high pressure pump; no fancy wiring just live to switch to pump then earth
Would this pump work just as I have described in the above paragraph
Would this work just like rigging a garden hose up to the inlet of the HP pump
Now going off what Jeff said and I’m guessing again; if I have read and understood what he was saying about the venturi working under high pressure and the bypass exchange effect wear you are constantly rotating the solution (chemical/water) through the bypass and each time you are adding more chemicals
What about if you just put the venturi after the bypass after all the heat exchanges so it is the very last thing on your equation like before the quick coupling on the machine

I don’t know much I’m just think and don’t know what I’m doing when it comes to machinery
Just playing the guessing game again I suppose

Batista

How dose a heat exchange work

its pumped from an 85 gallon tank mate

thanks
batista

May have solved the problem

After mucking around for too long with the original spitfire wiring schematic
I just have to except the fact that the design is crap
Every time I followed the wiring speck and no matter what I put in place between terminals 30 and 87 i.e. resistors diode lights the bottom float switch just welded together anyway

So instead of having 2 float switches why not just have one its child play to wiring it up into a relay compeered to wiring 2 switches up
Why! Because you will burn the pump out with the constant on off effect
If you had a 30 degree angel on your switch between on and off and the float was only 1” long then you probably have some thing like ½” between on and off wear by the pump fills the tank only by ½” then you add a rippling effect from the water coming in and out of the tank that switch is going to be on off twice a second burning out your pump very fast
Now if you wear to put an extension on your float which has a positive bouncy as long as you can get away with i.e. the max length of your mixer tank
Your 30 degree angel still stays the same but if the float was 1’ long then you have probably given your self something like 6” between on and off
as for the rippling effect get a bucket bore a hole through for the float switch connect pump power and relay block and test it with waving your hand about in the bucket of water just like I did and see how the pump pulses with the normal float switch and see how it doesn’t t with a 5” extension

I will see tomorrow how she fair up when I take the float switch down to the machine

P.S.
And I think if I was to fill the extension with water that would give it a neutral bouncy
Together with the original float it would have an ever slight positive bouncy
I’m hoping when the float is raided to the top adding water to it should sink it a little giving me more depth to play with

Ok so if the my float switch thing works tomorrow then I’m back in business
But there is the issue of the chemicals system
the venturi I have in operation at the moment is not the original hydra master venturi and will not suck any chemical; probably due to it being designed for high pressure and not low pressure like the on demand pump as it is situated between the pre heat exchange and the mixer tank inlet

Several things came to my mind
1. Locate the venturi before the demand pump so the suction between the demand pump
And the main tank would draw the chemical in
Problem would be you are putting chemical through the demand pump and the pre heat exchange and all the hoses to the mixer tank adding a scaling problem

2. Buy and insert a y/t piece coupling on the suction line between the demand pump and the main tank so the demand pump draws in water from the main tank and chemical from the chemical supply through the y/t piece coupling
Problems would be same as above and more expensive as I would have to by the fitting

3. Buy and install a chemical pump and wire it up to the demand pump
Sound a good idear as reading this forum I have heard a few people with machines have chemical pumps
I had a look on e-bay for chemical pumps and only found ones suited for dishwashers rated at 240 volts ac
Dose anyone who the right kind of chemical pump I need and who is selling them

Thanks

Batista