Condensate pump wiring

Group: alt.home.repair Date: Sun, Oct 19, 2003, 2:03pm From:
(Rick)
I have a newer Rheem RGRA gas furnace with a Rheem A/C controlled by a
Honeywell T8600D thermostat, and an Aprilaire 760A humidifier. I would
like to use the condensate pump's cutoff switch to shut down the A/C and
the humidifier water supply, but not the furnace, to avoid a freeze
condition. How can I wire the system to work? The alt.hvac guys were
less than helpful. Thanks.
--
Rick
++++++++++++++++++

John wrote:

No problem Rick, but you will need to add a relay or two. if you are not
comfortable doing this I would advise getting help. Make sure the
additional relays are installed on a small chassis or enclosure so as
not to likely short any wires or connections. I am just telling you how
it can be done.

I can not remember if the 760A water solenoid is 120vac or 24vac. If it
is 24vac you can use one SPDT 24vac relay, here are the connections:

+ (hot) side of the 24vac transformer that will be going to RH and RC
of the thermostat will go to one side of the pump safety switch.
+ The other side of the safety switch will go to the coil of the 24vac
coil relay.
+ The other side of the relay coil will go to the common of the 24 vac
transformer.
+ The existing wire at the thermostat terminal (Y) will need to go to
the common or switching contact of the relay. A wire from the (NO)
contact will go where the previous wire went from (Y) to the
compressor. Confusing I know but you are just putting the wire at (Y)
through the contacts and then to the compressor.
+ Put one side of the 760A solenoid through the other (NO) contacts of
the relay.

* If the 760A Solenoid is 120vac, use two 24vac coil relays and
parallel the two coils. Use the second relay contacts (common) and (NO)
to break the solenoid. I don't like to mix low and high voltage on one
relay, also label second relay as having 120vac on contacts.

John Wiliamson