What does the 'A' wire on my old Robert Shaw thermostat do?
#1
09-30-06, 08:53 AM
What does the 'A' wire on my old Robert Shaw thermostat do?
I am replacing my old Robert Shaw thermostat (model: D34020) with a new Honeywell thermostat (RTH7400). The Honeywell installation manual doesn't mention a wired connection labeled 'A', and the Honeywell telephone technical support doesn't know what it's for either. The new thermostat has the following terminals: C, G, Y, O/B, R, W2, Y2, AUX, E and L. Honeywell tech support says if they know what the wire does, they can help match it to the proper terminal. Unfortnately, support for Robert Shaw products isn't available on the weekend. Does anyone know what 'A' wire on my old Robert Shaw thermostat does?
Last edited by ellroy; 09-30-06 at 10:32 AM.
#2
09-30-06, 10:10 PM
Member
Join Date: Aug 2002
Location: Mountain Williams Missouri
Posts: 18,386
Received 0 Votes
on
0 Posts
Honeywell tech support says if they know what the wire does, they can help match it to the proper terminal.
Id check on that A color and see where it goes in the blower unit and what it does. I have no idea. One book I have say A is. Normal compressor opertion relay/always on in normal mode off in emergency mode.
This is out of a Hunter tstat set up
ED
Id check on that A color and see where it goes in the blower unit and what it does. I have no idea. One book I have say A is. Normal compressor opertion relay/always on in normal mode off in emergency mode.
This is out of a Hunter tstat set up
ED
#3
10-02-06, 02:36 AM
Member
Join Date: Oct 2006
Posts: 2
Received 0 Votes
on
0 Posts
On my Lennox system, 1984 vintage, the circuit diagram labels "A" as the "compensating thermistor." I'm still working on what implications ignoring that wire may have for installing a new stat.
