[Matt Gibson]

My machine keeps pressurising itself. basically when you turn it on, its fine for 5 seconds then it has to pressurized itself again. you can actually see the handle of the unloader creeping out before it re pressurises. Its fine when your using the gun. But when you are pulling the trigger it just re pressurized ever five seconds. now my guess is its the unloader that's knackered as when you turn the machine off the unloader hisses for about ten seconds but there are no leaks from any of the hp hoses/connections or the unloaded itself,

Any ideas what it could be before i buy a new unloader? Only had this one for 6 months.

Ps no air bubbles in the feed hose and water stops recurculating when trigger is pressed.

[Blast Away]

New unloader mate. Had the same last week and went to Tayburs for a new one.

[BDCS]

It can only be the unloader

[Matt Gibson]

I thought as much. just thought maybe it could be something small that i missed. got the pump off to change all seals/valves anyway, ill order an unloaded tonight.

just a side note, why do the unloaders wear out so quick? I've had it apart and everything looks fine.

Lee, was your doing the same exact thing? Ie always re pressurising ?

Cheers for the speedy replies guys! 

[BDCS]

I have a pile of old unloaders on the bench. We all stop and talk, clear up and leave the pump running which is when the full flow of water is rushing through the valve on one side and the captive pressure is trapped on the other. If you have a small leak on the hose or gun the the unloader is constantly hunting up and down. The other problem is running the engine / pump flat out with a slightly smaller nozzle than needed so the unloader is leaking a small amount of flow back to tank and hence wearing the seat / seal. The unloader should be considered a service part and changed with the valves every year.

[Matt Gibson]

I run a slightly bigger nozzle i think. but i check the return  occasionAlly when the trigger is pulled and there is no flow back. but i know what your saying, its got seals and moving parts and its under a heap of stress all day so its bound to fail.

cheers mate

[Advance]

Have you checked and made sure that the nozzle isnt blocked?

[Matt Gibson]

Yeah mate, only does it when im not pulling the trigger so count be a blocked nozzle