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mmspar 06-29-2010 09:48 PM

Need help with Honeywell thermostat
Hi and hope someone can help me out ....
Location: Houston, TX

I have a 1h / 1c system ...

It has:

1. Honeywell PC8900a thermostat
- it has 4 terminals
#1 Red wire
#2 White wire
#3 Green wire
#4 Yellow wire

2. A W8900 Remote Module in the attic

Thermostat has a mind of its own and somewhat complicated + the wife hates it.

I would like to replace it and a friend of mine recommends a Pro1 - Model T905. It seems to be "friendlier"

My question and fears are that it will not be compatible with item #2 - W8900 Remote Module sitting in the attic for whatever it does.

So, my question is if its Ok to change it or do I have to go a different direction ?

I have called Honeywell and their only response is that I have to get their most expensive unit + change module also. My take on talking to them is they are only interested on selling me another product.

It used to be very easy to change thermostats in the old days but now things seem more complicated. The only extra I see in this unit is that it has an extra vent coming from outside for fresh air + it has an electronic open/close device on it. That is it.

Original home builder was Pioneer.

Thanks a million to anyone that can help me out.

beenthere 06-29-2010 10:29 PM

The module should also be controlling your fresh air. That is a communicating thermostat.

It is a crappy thermostat though.

If you want a unit that still controls the fresh air intake. Get a Honeywell IAQ thermostat(YTH9421). Its also a communicating thermostat. But much friendlier.

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