mojorizing

No, the servo doesn't know the repositioned arm on the shaft. The servo only knows the angularity of the output shaft via the internal potentiometer.

After repositioning an arm the servo will try to do to get the correct temp. and if that's beyond the physical limits the servo will got to full stroke.

Come to think of it, could it be that your arm was installed at the wrong angle initially? Disconnect the arm and see if the servo operates as you manually regulate the air temp. Whatchathink?


Oh, gotta go, NASA is calling, they got a penguin stuck in the Rover, must of been that pop fly.
Kevin

DavidI

> could it be that your arm was installed at the wrong angle initially?

well..... The two replacement servos I was sent were both at 8 o'clock. I presumed therefore they were both removed from the RHS at cold. To fit one to the LHS I repositioned the arm by taking the bolt off and made it 4 o'clock. It wouldn't move but that could be because it thought it already was warm. i.e. it couldn't physically move to less than 4 o'clock, and wouldn't move to greater than 4 o'clock because so far as it was concerned it was at 8 o'clock and there is nowhere to go higher than 8.

I'll whip the arm off as you suggest and see what happens. Hopefully it will demonstrate the correct start/finish points and I can reset the arm.

Good luck with Pingu. I find tuna chunks entice the pesky critters out of most places.

DavidI

.... and it worked as expected. I removed the arm, adjusted it to the correct position and the HVAC now works correctly.

Many thanks for all the help - very satisfying to get it all working although there are quite a few bits of the system that are still something of a mystery!