Sabroe SMC 108 Loading/unloading

[hookster]

Hi all
After an oil pump failure the pump was replaced (new oil,filters etc)
Oil pressure is 4.8 Bar but only the 75% head will load up. Mechanical unloaders were inspected and all able to be operated manually.
Question
would two solenoid block valves be faulty?
and how would you assertain that valves are passing?
System is running on NH3
Any other suggestions on why loading is not working would be appreciated.

[tarcau mihai]

What kind of load regulation has your compressor?Slide valve which is controlled by oil pressure?

[hookster]

Yes oil pressure controlled piston onto slide linkage for valve plate lifters.

[nh3wizard]

If the 100% solenoid is energized, you might have some blockage preventing the oil to push the piston, is there a way to put a gauge on the line for the 100% and see if you have any pressure? This is assuming that there are 2 solenoids, 1 for 75% and 1 for 100%.

[Grizzly]

Hi Craig
When you manually inspected the unloading gear operation.
Did you have the Heads off to observe the pins rising and falling.
Did you check the loading gear linkages for excessive wear or a broken spring.
When refitting the heads did you use the special plugs to hold the loading gear linkage at over tdc?
The reccomended Oil Pressure is approx 4 bar. Which can be adjusted using the regulting screw near the s/seal end.
Steve.

[tarcau mihai]

On your compressor the load is not protected by motor current or high pressure?it could be a reason why is not loading just 75% if is on automatic or remote mode...if you put it on manual mode you can reach 100% of load?

[hookster]

Hi Craig
When you manually inspected the unloading gear operation.
Did you have the Heads off to observe the pins rising and falling.
Did you check the loading gear linkages for excessive wear or a broken spring.
When refitting the heads did you use the special plugs to hold the loading gear linkage at over tdc?
The reccomended Oil Pressure is approx 4 bar. Which can be adjusted using the regulting screw near the s/seal end.
Steve.

Yes checked wear and two sets of springs were broken on the 75% head

"When refitting the heads did you use the special plugs to hold the loading gear linkage at over tdc?"

Doh!! thanks steve
It all comes flooding back
Guess the job pressures getting the best of me!!

[hookster]

Sabroe minimum alarm oil pressure 4 bar?

[GHAZ]

Hello hookster as grizzly stated use a 3/8 bsp plug to push the linkage back and then lower the heads down tighten ,the bsp plug goes on the pulley side of the compressor near the top on squar blocks

[Grizzly]

message deleted by grizzly
as factually incorrect.

[josef]

Low warning 4 bar, low alarm 3,5 bar

[Grizzly]

Low warning 4 bar, low alarm 3,5 bar
My mistake josef sorry.
In my defence on the older Mk3 Machines which I believe this 1 is. 4bar is acheived more easily and still an acceptable differential.
Sorry Craig bum info!
Grizzly

[josef]

Hi Grizzly,
your answer is correct, I just added