Line Voltage Thermostat Question (cooling only)


Old 06-17-13, 05:03 AM
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Join Date: Aug 2002
Location: Pennsylvania
Posts: 96
Line Voltage Thermostat Question (cooling only)

We have a Carrier 15 ton rooftop unit with the air handler on the first floor (3 story building) All pneumatic controls which someone made a mess out of before I started here. Ok, I'm able to get the AC to come on manually and shut it off with the breaker. This has been working fine for a few weeks and now they are asking for some kind of temp control. Is it possible to put a line voltage thermostat on the primary side of the transformer (280V)? If not, is it possible to break a connection anywhere that would give some kind of control?
ps~reason for this is company trying to same money. ha!
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Old 06-17-13, 08:48 AM
PJmax's Avatar
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Your going to try "rig up" a control for a 15 ton AC unit that runs three floors.

You should have control wiring between the air handler and the rooftop unit.
You should try to incorporate a thermostat within that wiring.

Constantly disconnecting the AC is not going to be a good thing for the unit.

Maybe with the model number of the compressor we could help you out further.
Old 06-17-13, 09:29 AM
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Join Date: Aug 2002
Location: Pennsylvania
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I'll get the number of the compressor for you. No, this unit doesn't run all 3 floors, it just takes care of the front part of the first floor. If I run it for about a hour they are good for the whole morning, and just now I turned it on again and I'll shut it off for the day in about an hour.
Old 06-17-13, 10:19 AM
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OK, the model is Carrier 38AE014600 R494224, hope that helps. joe
Old 06-17-13, 03:42 PM
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Join Date: Jan 2011
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page 18 and 19... you should be able to use a 24V thermostat. They make plenty of wireless thermostats now. You need to know how the system is controlled (voltage wise - not pneumatic wise) in order to determine how to make it work with a conventional thermostat.

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