frank
16-04-2003, 08:34 PM
came across an odd one last week with a 200kw chiller that had been faulting with ice build up on the shell and tube evaporator.
The unit had a sol valve prior to the tev but the LP switch was wired through a timer (solid state).
If the system went into low pressure then the LP switch energised a timer which eventually energised a fault contactor to stop the machine. has any one come across this?
As the comp continued to run in low pressure it pulled a vacuum before the contactor made and stopped the machine With a high vacuum on one side of the sol valve and high liquid pressure on the other the electro coil was not able to energise the sol valve and the machine just ran in a vacuum after it was called.
to solve the problem I had to fit a new Ranco LP, scrap the timer and do a few other mods.
Why fit a timer in the LP?
The unit had a sol valve prior to the tev but the LP switch was wired through a timer (solid state).
If the system went into low pressure then the LP switch energised a timer which eventually energised a fault contactor to stop the machine. has any one come across this?
As the comp continued to run in low pressure it pulled a vacuum before the contactor made and stopped the machine With a high vacuum on one side of the sol valve and high liquid pressure on the other the electro coil was not able to energise the sol valve and the machine just ran in a vacuum after it was called.
to solve the problem I had to fit a new Ranco LP, scrap the timer and do a few other mods.
Why fit a timer in the LP?