[Matt Gibson]

Right, im looking for an answer to a puzzling question. ive thought about it but i cant work out why it is happening.

when i pull the trigger there isnt instant pressure at the lance. there is a shot of full pressure (exactly like if you pulled the trigger to release the pressure with the machine off) then the pressure builds up until it reaches full.

most machines ive ever used its been a case of pull the trigger and get instant pressure. ive used the larger electric karchers and they seem to work similar to above, where the pressure has to build.

i have a trapped pressure unloader on it too so i thought i should be getting instant pressure. can someone explain why some machines are jnsta t and some need to build pressure?

[Blast Away]

K5 Unloader mate

[Blast Away]

This might help http://www.epowerwash.com/wp/archives/631

[Matt Gibson]

What you mean mate?

[Matt Gibson]

I know how they work mate, although i did learn a few things reading that.

what i want to know is why some machines have instant pressure and some dont. both my machines have trapped pressure unloaders but one give instant pressure and one needs to build up pressure when trigger is pulled. i was just curious as to why some machines need to build up pressure.

is yours instant as soon as you pull the trigger mate?

[Rob_Mac]

Matt

The H & M, Thor and my four Hilta/Yanmar are all instant pressure. I have never come across this. Even my old machines have all been instant.

Rob

[Blast Away]

We've got these

and we have a K5.3

[Matt Gibson]

Ive come across it before, mainly on electric machines.

lee, i use the top pic on my van mount. solid unloaders them.

[Kenny83]

matt the reason you get a shot then pressure builds up on electric machines is because the trapped pressure builds up to ebngage a pressure switch, this turns the machine off, when the trigger is pressed the pressure is release thus disengaging the pressure switch and then the mototr kicks back in, obviously the motor will start from stop or tickover so the pressure will build up in line with this (usually withina second or 2)

Hope this helps? wasn't sure of the question your asking?
 

[Kenny83]

matt the reason you get a shot then pressure builds up on electric machines is because the trapped pressure builds up to ebngage a pressure switch, this turns the machine off, when the trigger is pressed the pressure is release thus disengaging the pressure switch and then the mototr kicks back in, obviously the motor will start from stop or tickover so the pressure will build up in line with this (usually withina second or 2)

Hope this helps? wasn't sure of the question your asking?

 

Also normal engined machines have trapped pressure unloaders but instead of a pressure switch, they go to bypass, the engine stays at the same speed and it just switches from by pass to the lance, because the engine doesn't need to pick up speed the pressure is constant/instant

[Matt Gibson]

Ahh ok mate. my main question was why would my machine get that kick of pressure then build up if its an engine driven machine with a trapped unloader?

[Kenny83]

does it have a low rev facility where as when you press the trigger it revs up to speed?

[Matt Gibson]

No mate. it sits on 1750rpm and when you pull the trigger it loads up but the revs dont change hardly at all.

[Kenny83]

ok, exactly what machine is it mate? is it a dirt driver? aquilla? demon?
Also what model is it? what engine is on it?
Thanks

[Matt Gibson]

Its a flowplant trailer. lombardini engine. its the 3 cyl.

Not sure of the exact model, they only have a couple of different trailers. its got a hawk pump on it.

[Kenny83]

is this yours?
http://www.flowplant.com/H3004D.pdf

[Matt Gibson]

Yes mate. pretty much. except i have the hawk H5061 pump. its says on hawks website thats its 15lpm but the sticker on the pump says 18lpm.

The engine is a Lombardini LDW1003

[chris scott]

The first " kick" of pressure when the trigger is pulled will be the "trapped " pressure in the line between the trigger/hose/unloader releasing . . Hence trapped pressure unloader. Soft unloaders like the K5 are a better option as triggers,unloaders engine woodruff keys etc generally last a lot longer with "soft start" unloaders Depending on the length of the hose it could take a second or too to replenish the pressure. Old hoses also "swell" a bit first coupled with a long length could give you a slight delay...but it would not be much.

[Matt Gibson]

Chris,

The delay im getting is quite a bit. when i first pull the trigger it drops to about 40 bar and has to work its way back up to operating pressure.

my other machine, and most other engine drive machines ive used give me instant pressure with the pull of the trigger. no drop in pressure at all.

[chris scott]

Send me a picture. Is it gearbox driven? It's not something daft like a cush drive/clutch slipping initially? Disconnect everything and run it as a basic pressure washer ie engine, pump,unloader,lance. ( I take it this is the machine with the boiler etc)