VN-42 Not Driving VNails - mostly AGAIN

[Larry Peterson]

I had an issue a couple of weeks ago with my VN42 not driving nails and it was fixed - or so it seems. Here is the thread that talks about that. https://www.thegrumble.com/threads/vn-42-not-driving-vnails-mostly.88189/ Problem - VN-42 Not Driving VNails - mostly

It was fixed by replacing the Piston Driver Blade. That fixed the problem - sorta.

Since then it has worked partially. When I start up in the morning, it will drive the vnails for 2-3 frames and then take a break. literally. It will drive a vnail and then for the next one in won't. If I let it rest/reset/rejuvenate itself for a couple of minutes and then go back, it will drive a single vnail and then it won't so i let it "rest" for a couple of minutes and its good to go for exactly one vnail. So I drive 1 vnail, go do something else for a couple of minutes, drive 1 vnail, etc. Not very productive.

So this morning it appears to have gone on a permanent break. I did one frame normally and one the second frame it went into its drive, then rest routine. I go the second frame done and part of a third and now it won't drive vnails at all.

So it appears that some other component has gone bad.............but which one. Here are a list of replacement components the FT sells. Hopefully it is one of them.

Foot Pedal,Touch Lever, Pushbutton Control Valve (732290002)​

There is another control valve 732440003 that isn't listed in the store. The VN42 uses 3 of them.

Pressure Regulator (735630002)​

Product Number: 41-599​

I replaced this a few years ago.

Soft Clamp Regulator (735130006)​

Solenoid/Valve (732140004)​

That's basically all the replacement parts that they sell at https://shop.fletcher-terry.com/collections/pneumatics Pneumatics | Shop Fletcher Terry

Any suggestions. I am apparently dead in the water until I figure this out.

BTW, I do have sufficient pressure. When the vnail doesn't drive it sounds like there isn't enough air pressure to drive it but the pressure gauge reads OK (about 100 psi).

One of the suggestions in the manual is an excess of water or oil and to
"Remove the surplus of oil and water from
the valves by disconnecting the air lines
one by one, forcing out the water with
the air"

There are a million lines. not sure how to go about this. Has anyone else done this?

 

[Underpinner Spares]

Larry although there are a number of components that can cause Alfamacchine firing issues the main one is the control valve, there are 3 control valves fitted to your machine and each one controls a specific movement:
Hammer firing
Vertical clamping
Horizontal clamping

If you are confident in working on your machine then the easiest and free way to determine whether it is the valve causing issues is to swap the Hammer firing valve with the Horizontal clamping valve as the valves are identical, this way if the valve is at fault then the fault will transfer itself to the Horizontal clamp and the Hammer will fire correctly.

if this confirms the valve is faulty then just purchase a new valve or a control valve seal kit at a later date.

(P.S, always take a photo before swapping any valves as then you have a visual record of where the pipes go)

Good luck!

Mark

 

[Larry Peterson]

Thanks for the help. In looking at the diagram below, it appears that the middle control valve (#19) is the one that controls the hammer firing. It also looks like the bottom air feed for each valve comes from a common source so I don't need to change those out when I test. I can't tell from the diagram which is the vertical clamping and which is the horizontal so I will have to look closer tomorrow when I try this.

 

[Underpinner Spares]

The schematic diagram shows the valve on the left is the hammer valve, the middle one is the vertical clamp and the right one the horizontal clamp.

(the default layout on the machine is the lowest down of the 3 valves is hammer and the top one of the 3 is the horizontal clamp)

 

[Larry Peterson]

Update. I never posted what the resolution of this was. The bottom line is that I never got it working and retired the VN42 and replaced it with a U-400.