Today I did a last minute upgrade on an oven system to convert from an old mercury temperature controller to regulate air to a Steam servo valve to a Digital controller with an IP valve.
I have a problem with the IP valve oscillating when the controller wants more than 10 LBs of air to open the servo valve
Now I noticed if I shut it down to 0 output and then call for lets say a 15 LB output, It then some times will get up there smoothly with out oscillating..
One other observation, the unit I pulled out of stock is used where some one obviously exchanged the main unit with a used one but leaving the new cover.. Is it possible the valve is defective? We don't have another in stock at the moment.
P.S. I checked the output signal from the controller, it holds a steady 20 ma current while it's trying to open the IP valve to max position and the incoming is also regulated at the 40 LBs of supply as per labeled on the IP valve.
Is it possible this valve is defective ? since it works fine under 10 Lbs and appears that it was already in service at one time. The rated output is 3..15 Lbs normal., but we have these same valves on other equipment where they don't oscillate and even run higher output LBS..