NCM300 - Use of Honeywell Prestige IAQ with EIM

[srsnitkin]

I have an NCM 300 Zone Control system and need to replace the thermostat we use for zone 2. The placement of this thermostat is a problem and I want to solve this with a Honeywell portable thermostat (REM5000R1001) that we can move from room to room. To use this portable unit I need to install either a Honeywell Prestige 2.0 HD (THX9321) or a Honeywell Prestige IAQ (THX9421) and I plan to put it at the current location.

Currently we have a Honeywell T8000C thermostat which is connected with only 4 wires (R,W,G,Y). If I use the Prestige 2.0 HD (THX9321) I need 5 wires at the thermostat (R,W,G,Y,C). I have spare conductors in the cable but I want to confirm that I can use the zone 2 C terminal on the NCM 300 for this purpose.

If I use the Honeywell Prestige IAQ (THX9421). The Prestige 2.0 HD requires 5 wires at the thermostat (R, W, Y, G, C). The Prestige IAQ will be connected through a Honeywell EIM which I will mount near the NCM 300. The EIM needs 24VAC power to work and I assume that I can just connect this unit in parallel with 24VAC power to the NCM 300. Is that alright? The thermostat only needs 24VAC power which I would provide from terminals on the EIM. In that case, I assume that I would only need to connect 3 wires from the EIM (R, W, G) to the NCM 300. Is that correct?

If either of these approaches will work, are there any other reasons why I should consider one option over the other?

I sent a separate email about this topic, but then I though that others might benefit from this question. So please just disregard that email.

Thanks for your help.

[Erik W.]

Either thermostat is perfectly adequate for your application, but in either case you need to have a C wire to provide 24 volts to the thermostat.

Erik Wnoroski
EWC Controls, Inc.
385 State Route 33
Englishtown, NJ 07726
800-446-3110 ext 483