For the chem side to work properly you need a High / low pressure head (rose Nozzle) it replaces the standard jet / nozzle holder and can be dropped to low pressure to pull chemical through. As a general rule most chem pick ups won't work on longer lengths of hose, it depends on the system to be perfectly honest.
There is a throttle set-up on the machines as well as governor adjustment which is used to set the machines initially, throttle springs do wear over time etc so this may be worth looking at too.
Pressure gauge wise do remember that you will only get your true pressure by putting a gauge direct into the head of the machine - the result from a gauge placed after the unloader valve will be 20-30 Bar less
Ok Ben,
Ok, you have made a couple of interesting points, firstly, now I think about it I'm sure it hasn't the same amount of throttle as yours (is there a throttle stop on these that may work loose?) I don't have a pressure gauge but I have gone through adjusting the unloader by winding all the way in ( low pressure ) then winding out, the pressure increases until a bout 3/4 open then remains the same, the bolt can then unwind all the way out with no change so I presumed the valve is at max, so I wound it back it until I feel the bolt touch the valve then turned it in another 1/2 turn.
Both machines were using same age hose and turbo nozzles, although I didn't swap them over there's not a not of usage/age difference
Also Ben out of interest I've been told that a 'soap' nozzle is needed for the chemical injector to work is that correct?
Darran