[Matt Gibson]

Ok,

So as per my other thread about this new machine I've bought, and the way its set up. Above is a pic of the second unloader. Just out of shot i have a normal unloader, which is fed from my pump, then there is a RTT from it and then there is an outlet which goes to where I've labelled ''outlet from other unloader''

then it looks like it goes through a second unloader and into the boiler, then from the boiler to the hose reel.

What is this second unloader for? to make sure you don't over pressure and blow the boiler tube? I've never ever seen this second unloader on any machine. my other machine has all the hoses set up the same, with a built in boiler and I've only got the single unloader.

Next question, my gauge reads correct pressure when the trigger ISN'T pulled, when i pull the trigger it drops to zero. Is this normal? my other machine is the opposite, reads zero when the trigger isn't pulled, and reads pressure when I'm pulling the trigger. Also, on the new machine, if i wind the unloader up/down without the trig pulled, the pressure doesn't change, its only after ive pulled & released the trig that the new pressure reads.

Any ideas? Im not sure if its normal, as I'm used to my other machine.

[BDCS]

The first unloader is the main unloader, the second which is pictured is fitted in place of a relief v/v - this will do the same job as a relief but dump back to tank. The unloader in the picture should be set at the boiler max rating and the first closest to the pump should always be set lower than the one in the picture. The guage your looking at shows the trapped pressure between the two unloaders. Its not the perfect set up but it will work. Read the other thread and fit a bloody nozzle before you attempt to set any unloader as the nozzle dictates the pressure in the system. To maybe help the situation - wind the unloader in the picture right in ( clockwise ) and throw away the numpty and then refer to my other post on this subject. It might be easier if I came up and set it up for you as I' failry close only being in Dover 

[chris scott]

Why dont you connect the pressure gauge up to the hp side directly on the pump head ( by way of a hp pipe to your gauge on the control panel) this will give  a better indication as to what you are producing in terms of pressure (should also help with cooling of gauge). Your second "unloader"is not an unloader  (or shouldn't be !)but a safety valve. Something like this... http://www.aspw.co.uk/index.php?main_page=product_info&cPath=12_145&products_id=1224 As Carl said to protect the boiler.

[BDCS]

Why does k n o b come up as numpty - the moderators should consider the context that the term has been used before the word is changed as in this case it was not used nor intended in any derogoratory way whatsoever. Maybe the moderator could suggest an alternative term that they would consider to be more suitable. Who is the moderator on this poor relative to the carpet and window sections - I thought Tosh was just in charge of the religious and racist infringements  Just what is pc for the black (read coloured ) lump of plastic used to adjust and adjustable unloader ? Does our moderator know what and unloader is   

[Matt Gibson]

Right,

Thanks for that guys very informative. I had a feeling from what carl said in a previous post that the second unloader/safety valve was to protect the boiler but i thought id get a pic and confirm it. I have a PRV on my other machine, but it doesnt have the spring and isnt adjustable, i think its an interpump one. so its the same in theory.

As for the gauge, i was going to fit it from the gauge port on the first unloader, but i didnt have the correct fittings so i just put it back where it was for the time being. might go and get some fittings and hose made up to have it on the first unloader.

I did have a nozzle fitted when i was testing it. The correct nozzle. My point about setting the pressure was, that when the machine is running with the trigger closed, and i wind the unloader, it doesnt alter the pressure, but from what you have said, im guessing thats because the gauge is reading trapped pressure and trapped pressure cant be altered until you pull the trigger and the new pressure reading shows. Also, both my machines have non adjustable revs, hence why i need to play with the unloaders on a day to day basis to adjust the pressure for different things. I cant just knock the revs back.


Carl, mate just pop over when youve got a spare five minutes 

[Matt Gibson]

This machine is doing my tits in. new unloader when i bought it. machines only been run a few times since. all ive done is play around with the gauge. i moved it so the gauge is connected to the first unloader.

Now when i pull the trigger im only getting about 1500psi but when i release the trigger the gauge pressures up to just under 3000psi.

i just dont know what the problem is. unloader seems to be working fine. last time i ran it with the old gauge set up it ran fine and the pump gave me 200 bar. im about ready to burn it.

[BDCS]

For a start get a guage that you KNOW reads the correct pressure. Screw the guage in instead of the nozzle and set both unloaders at 250 bars, Take care when removing the nozzle.

[Matt Gibson]

I know the gauge is reading right. i can feel that the pressure is nowhere near 200 bar. but when i release the trigger the system pressures up to 200.

Basically ive set the unloader to just under 200bar. pull the trigger and it gets to about 1700 psi. release the trigger and it pressures up to 200 then starts unloading.

[Matt Gibson]

Just checked and when trigger is pulled there is not rtt. but i can feel that its nowhere near 200 bar. this a pump issue? I just checked all the valves. They all seems in good condition.

[BDCS]

Does the pump get at all hot ? Have you got a new nozzle of the correct size ? How do you get 200 bar to unload when you have said you've set the unloader to just under 200 bar ? I'd wind both unloaders to max and see what pressure the nozzle gives you then when you know that you get 200 bar with the nozzle set the unloaders - the one closest to the pump about 100 psi over the nozzle pressure and the second 100 psi over that. Where is the guage now ?

[Matt Gibson]

I dont think im doing a good job explaining. pump stays cool. ive got a brand new nozzle of the correct size.

i have wound the unloader up fully. pull the trigger and the gauge reads about 80bar. There is no water being rtt.  release the trigger and the needle goes up to 200bar and the whole system pressurises and then it starts rtt.

Does that make sense? Sorry, im just getting frustrated because it was working fine last week.

someone mentioned the seals might be gone and thats why im not getting full pressure?

[BDCS]

Then if everything is as you say then I would say there must be a problem with a valve - it won't be a piston as there is no leakage at the pump between the crankcase and pump head. So without flow you have pressure but when you need flow to make pressure you don't have full flow so you get reduced pressure ? A valve ! Buy a new set anyway just to rule that out !

[Matt Gibson]

That makes a lot of sense!!

Someone mentioned seals so i was going to pick up a set so ill grab a set of valves while im at it an do the whole lot.

Dont know why it worked last week and now its knackered?
Its only been run to test things and even then for short periods.

[chris scott]

Its not a blocked filter on the l p side is it ? It wont produce pressure if its dumping (through the nozzle) more than it can suck.

[Matt Gibson]

No mate, filter is clear. checked all the hoses on the lp side too for leaks or if any air was being sucked in. everything looks spot on. 

[chris scott]

Disconnect everything and rearrange it to simple pressure washer config ..engine, pump, unloader (1).hose and gun. See if that makes any difference. Start with the basics and add more to it.

[Matt Gibson]

Well i changed the seals and its not that. got a set of valves on order but i do t hold out much hope either. looks like an expensive trip to flowplant next week.

[Matt Gibson]

Right,

Changed the seals, no different. Im getting about 2600psi max. Basically what's happening is if I pull the trigger, and wind the unloader up until im making 3000psi, when I let go of the trigger it pressures way over 3000psi before it starts RTT and water comes out of relief valve (doing its job obviously)

 Now I understand that if im running it dead on 3000psi, when I let go of the trigger its going to go a little bit above before it unloads, but I have to run this machine way below so as not to over pressurise when trigger is released. I know this is probably something simple that you guys have come across before but im not explaining it well enough  

Got a new set of valves waiting to go in, but removed existing valves an they look new.

EDIT: Had an ex Flowplant engineer up to have a look at it, he checked the valves/unloader/seals etc and said everything looks fine, and that the pump might just be worn hence why its not making the full 200 bar when the trigger is pulled. I was under the assumption the pump is the sum of all its parts, so if you replaced enough parts the pump couldn't get ''worn''

He also said that some of these machines, from new, from the factory have arrived with 200bar pumps on them, and the Flowplant guys have had to put 04 nozzles on them just to get them to achieve 200bar. How can this be right if the pump is rated at 200bar/18lpm surely you shouldn't need to put a smaller nozzle on to achieve the stated pressure, specially with a brand new machine.

Am getting fed up with it because i want to put a 21lpm pump on it, but if this issue isn't pump related, then I'm not going to solve it by changing the pump and am still going to have the same problem regardless of what pump is on it.

[Kenny83]

long shot but your revs could be too low? there fore your over pressuring your unloader by turning it tight so when you let go it's over 250 bar to unload, hence the reason the the pressure relief kicks in, try putting the right jet in, ie, 045 if it's a 15 litre machine, then if all the seals, valves and unloaders fine, turn the throttle governing screw untill your pressure is up.... thats what it sounds like to me mate, revs are too low

[Matt Gibson]

The right nozzle is a 055 as the pump is 18lpm @ 200 bar. but im running an 05 in it. also its got a rev gauge on it and its running at 1750rpm which is what the pump is rated at so everything is set right.

ive got a spare ws201 in the container so im going to put that on this week and if i still cant get full pressure ill know its the system and not the pump.

just got me scratching my head.