heating/cooling

Reply

  #1  
Old 06-30-04, 08:11 PM
keith fore
Visiting Guest
Posts: n/a
heating/cooling

My husband and I are new to DIY and we love this web site. We are seeking anyones help with a heating and cooling question. We have a 3 year old Carrier Weathermaker 8000 two-speed furnace. We are looking into adding a central air conditioning unit to it. However, when the heating unit was installed, the booklet was not placed in or near the furnace. We are in need of a diagram to wire a new thermostat with the new cooling unit.. I know we could contact Carrier for it, however, it would take time to recieve it. If anyone can help us, we would greatly appreciate it.
Thank you,
Diane
 
Sponsored Links
  #2  
Old 07-01-04, 05:14 AM
Spark Chaser
Visiting Guest
Posts: n/a
  #3  
Old 07-01-04, 09:00 AM
Member
Join Date: Feb 2002
Location: port chester n y
Posts: 2,117
This presumes the existing furnace/blower unit is equipped with a 24-volt gas-valve, a fan-relay, and a control-power transformer. One terminal of the control-power transformer is indentified "R", and the other terminal "C".

For the existing "heat-only" operation there is a 2-wire thermosat cable with Red and White wires between the thermosat and the furnace/blower, with the Red wire connected to the "R" control-power transformer terminal , and the White wire connected to the gas-valve.

On a "call-for-heat", the thermostat completes the internal circuit between the Red & Whire wires, and the gas-valve operates.

To progress to both heating and cooling, a heating/cooling thermostat with "R", "W", "Y" and "G" terminals is connected. The heating circuit is connected as before to the "R" & "W" terminals. If the thermosat has "Rh" (heat) and "Rc" (cool) terminals, the Red thermostat wire "jumps" between the terminals.

There is a 2-wire, low-voltage, control-power cable connected to a contactor inside the out-door condensing section of the cooling system.One wire of this cable connects to the "C" terminal of the control-power transformer, and the other wire connects to a Yellow wire that connects to the "Y" terminal of the thermostat. For cooling, the thermostat completes an internal circuit between the Red & Yellow wires, and the control-contactor in the condensing section operates and switches 220-volt power to the fan/compressor motors.

One wire of the control-coil of the fan-relay connects to the "C" terminal of the control-power transformer, and the other wire connects to a Green wire that connects to the "G" terminal of the thermosat.For cooling.the thermostat completes an internal circuit to the Green wire and the fan-relay operates and switches power to the blower which circulates internal air across the evaporator (cooling) coil.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'