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View Full Version : sideloop to share a VMA A.I. 1



stuckagain
09-10-2008, 02:39 PM
I have a Johnson VMA1420
I am configuring it with the HVAC pro software tool
Q n A ,assigns A.O.1 for supplemental heating output (VALVE 1) OK
I also have a sideloop for heating (VALVE 2) A.O. 2 OK
The two valves are very close to eachother and should operate together
I want everything to use A.I. 1 (Zone Temperature)
however the Q n A assigns the sideloop temperature input to
A.I. 3 ,there are no options, NO good
This means I would have to run a seperate temperature sensor to A.I.3
Is there a way I can have the sideloop and the VMA both use A.I. 1 for temperature input

exwtk
09-10-2008, 06:31 PM
If the two valves should operate together, then why don't you just wire them together to AO-1 ??

bob_scheel
09-10-2008, 08:46 PM
Why do the two valves operate together? Is this a 1/3rd 2/3rd pair of valves on the same coil?

stuckagain
09-10-2008, 08:57 PM
I was over at the distributor of the valve actuators shortly after my post.
They also advised me to do the same thing.I was not sure if you can do that,although, I did remember that I used to wire a master and a slave actuator the same way.Providing that the transformer polarity,and the output is 0 to 10 volts,you can have up to 20 actuators off of the same AO.
I was under the impression that it was an amperage issue.He told me that actuator works on impedance levels.I am not quite sure what that is.All I know is that impedance is a resistance to current flow in an AC circuit.Some of the older actuators use to work on the Wheatstone bridge principle.At any rate the problem is solved,even though the solution is a little messy.But I thank you for your help.