Pressure switch to micro switch distance

I think you have one of two things going on hear, an overpressure problem or a carburetor issue with the engine.

Likely the door latch microswitch. My micro/convection oven has 4 of these, and they do go bad. I've had to replace two of the switches in 4 years.

replace a new pressure switch and tube

Your concern is very well placed, at pressures that high a lot of damage can be caused by a failure. According to the manual for this model air compressor the approximate cut-in pressure is 160 psi and the approximate cut-out pressure is 200 psi. Meaning it should pump up to 'about' 200 psi and shut off and not come on again until it gets down to 'about' 160 psi. They say approximate and I say about because it's not an exact science setting the pressure switch. Spring rates are not always exact, pressure guages are not that precise, etc. When turned on, it should shut off at 200 psi +/- 10 lbs. If it goes more than 10 lbs over that (220psi), I'd recommend you get the pressure switch and or guages checked or replaced.

When the trigger is released, pressure builds up and this acts on a valve (spill valve or pressure control valve). When this pressure is big enough it will push the spill valve out and closes a micro switch. Now this Spill Valve gets stuck sometimes, mainly due to soap and chemicals...so the micro switch is not closed...so the machine contiues running. If this is left likee this it will cause damage to the valves. So all one has to do is service the spill valve or as I usually do I replace it. There are cases were the micro switch is damaged also..and needs to be replaced. To see the spill valve and micro switch you must open the cover. The spill valve is located where you see a cover with an electric wire coming out of it. If the micro switch is good...you must tackle the Spill valve.
Regards,
fulltech.

You gave a very close solution yourself for the problem. But other leakages can cause such symtoms.Forexample a leaking head or a leaking chemical inlet. These can be caused because the spill valve (pressure control valve) is stuck. When this valve stucks it will leave a micro switch ON. So the machine keeps working with the gun closed. This will in turn creat internal pressure and damages the head, valves and chemical non-return and even damage outlet hose. So besides fixing the leakages you must check and service the spill valve. I often replace the spill valve. One must also checks if the micro switch is faulty. Now very important that what you mentioned that the machine cycles at one minute intervals, with trigger closed...this is most probably always the spill valve fault. If you open machine you see a place where there is a wire..this belongs to the micro switch...under you find the spill valve. Intake and suction valves may now also have a fault. Also there are systems with non-return valves at the machine outlet. You have to tackle by elimination. Fix the leakage..then tackle spill valve and micro switch.
Fulltech.

The first thing is that for sure the screw thread on the machine or at the end of the hose is damaged. Now it seems thar when you close the trigger the machine is not stopping due to a spill valve problem or micro switch problem. You are a bit lucky that the hose blows off, because if the hose stays in place, with this problem...more damage is done to the machine, especially the intake valves. Now the spill valve is a control valve that when there is presure built up, the valve moves and makes off a micro switch. This Spill Valve often gets stuck with detergent or chemical. So the Micro switch stays ON. Thus the machine will not stop...and blows the weakest point. Now you can either service the spill valve or as I do, replace it with a new one. To locate it you have to open the cover, and where there is a wire coming out at a place...there is the spill valve. First check the micro switch...then tackel the spill valve. As a general rule one must always rinse with clear water after using chemicals and soap. If these are left there..problems with the automatic stop of the machine will start to give trouble.
Fulltech.

I had the same problem . The micro switch needs to be replaced . All push button micro switches have a certain amount of "clicks" before they loose ability to make a good contact . Your left click switch has exceeded its life and can no longer make a clean contact without more pressure . Eventually the spring in the switch will fail thus stick permanantly.You will have to take it to an authorized Sony Service center or maybe an office machine service department might have the replacment . I fixed my own with an old mouse microswitch .

Per the User's Operating Instructions you want to check the condensate drain. Make sure it is free and clear. Also check the ingnitor, ensure there is no debris or buildup that could prevent it from firing properly.
Also, here are the Installation and Service Instructions that might be of help to you.

Without being onsite with toolbox in hand, I hope this information is very helpful to you. :-)

Dear emmettbrickw,
Many of the models of Karcher machines, have a valve that under pressure...will compress and at the same time it will let water by-pass and circulating inside the head. As this valve compresses it also puts off a micro switch. This all happens when the gun is closed. This valve is called a SPILL VALVE or sometimes a CONTROL VALVE. Now for various reasons (example you store the machine with pressure in the system)....the seals of this Spill Valve get damaged. So you can have a problem in which the machine stays off....or a problem like yours...the machine continues running with gun closed. Your problem with gun closed...the spill Valve is not compressing and therefore not stoping the machine. At first when this happened it caused a fault also in your machine's valves. The gun was closed...pressure grew high...and this burst the intake valves for sure.
So my advice is that the spill valve must be renewed and also the intake valves. You must also check the Miro-Switch to see if it got stuck in the on position. If micro-switch is faulty, this also must be renewed. The Spill Valve is often located where you find a micro-switch holder with an electrical wire coming out. When you find this micro-switch...detach it from machine...then put on machine for a few minutes and press micro switch to see if machine stops. If machine stops...then at least Miro-Switch is OK. Always do these tests with electrical protective clothing, Shoes and Gloves!! Now if your machine does not have a micro-switch...then you have a spill valve which only by-passes water. This type of spill valve also needs checking and if need be renewed.
In a few simple words, the spill valve does all the work after one has opened or closed the gun. Sometimes by changing the spill valve only....the pressure will get back to normal. If not ...suction and delivery valves must be checked.
Regards,
Fulltech.