chickenstrip76 Posted July 17, 2011 Share Posted July 17, 2011 We have an R model with flight station and cargo a/c problems. The a/c is running full hot, no matter the setting. We have checked out the control box, and the temp control valve, both are working fine. When selected to hot, the temp control valve opens, when selcted to cold, it closes, so these are not the issues. I was wondering could it be 2 failed anit-ice valves? I was messing with the a/c anti-ice control panel with power on. The "open" lights both work. But, when I move the switch to the "open" position, the "open" light does not illuminate. Both gripes showed up a day apart. The aircraft was on det, and the flight station went out. The next day, cargo did the same. I need help! Quote Link to comment Share on other sites More sharing options...
Railrunner130 Posted July 17, 2011 Share Posted July 17, 2011 I'm a Loadmaster, so I'm probably not the person to answer this. Take it with a grain of salt. We had a similar issue not too long ago. They ended up replacing the filter sock on the A/C Turbine and that resolved the issue. Hope that helps! Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted July 18, 2011 Share Posted July 18, 2011 When you say "No matter the setting" I ASSUME you mean in AUTO and the setting is with the rheostat knob.. Do the AC units go full HOT in Man? "R" model with anti-ice? Only four of those aircraft that I remember... anti ice was for the intake and did not interface with temp control... Take the cannon plugs off the Temp control box and "jump" B to E and C to F; that will give direct control to the FE. The manual temp select switch will directly control the temp control valve. No duct protection is avalible so caution is the needed... Quote Link to comment Share on other sites More sharing options...
chickenstrip76 Posted July 18, 2011 Author Share Posted July 18, 2011 A/C went full hot in man and auto. Its looking like we have 3 failed valves. All the same part number, just used in different places. Flight and cargo run hot, and underfloor heat temp does not regulate, and to quote the aircrew write up, "Simulates the surface of the sun". Just seems weird that all three valves would fail in a short period of time. Quote Link to comment Share on other sites More sharing options...
steve haigler Posted July 18, 2011 Share Posted July 18, 2011 I agree w/ Natops1 look at the cannon plug and the pins under the flt. deck. Quote Link to comment Share on other sites More sharing options...
NATOPS1 Posted July 18, 2011 Share Posted July 18, 2011 I think only two of them are the same.... the underfloor heat is different...it divertes more or less HOT air not mix cooled air and warmed air.... and both (or all three) valves bad with the same issue full hot.... The valves only do what they are told to do. In Manual there is nothing to drive the valve except to cold. The butterfly (inside) may not be closing but it soulds like it is in manual. In auto you may have a bad duct anticipator that should limit the speed in which the valve can move to full hot. Quote Link to comment Share on other sites More sharing options...
chickenstrip76 Posted July 27, 2011 Author Share Posted July 27, 2011 Turns out it was the low limit ice control valves in both systems. Then, after flight was changed, the temp control valve was found to be failed in the closed position. Basically, we had 4 valves fail at roughly the same time. Quote Link to comment Share on other sites More sharing options...
Jim Denney Posted November 4, 2011 Share Posted November 4, 2011 Does it have a Turbine By-pass Valve in the system? I've seen these fail in full by-pass and cause a problem. Also will fail in full closed. Quote Link to comment Share on other sites More sharing options...
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