On May 25, 8:22*am, "
wrote:
On May 25, 8:05*am, Pointer wrote:

Have a Little Giant VCMA-15 condensate drain pump with a pan overflow
switch. *The pump has two low voltage connections coming from it which
have been wired together for the 13 years that the installation have
been in the house. *These connection I presume are for the high level
switch in the reservoir tank. *Why are they wired together. *It would
seem to me that both the pan overflow and the high level switches should
be in series with the thermostat circuit. *What is the correct wiring
for this pump? *What am I missing here?

Looking at the install manual online for a VCMA-15ULS there is only
one switch and it has both NC and NO contacts available. * What
you do with either of them is up to the installer depending on the
requirements of the installation. * You would use the NO connection
in the thermostat circuit to turn off the furnace and/or AC if the
water level exceeds the max. *Where you wire it in the thermostat
circuit can determine if it cuts off just heat or cooling or both.

The NC contacts could be used to wire into an alarm system
if you prefer that instead of the cuttoff approach.

I think you have it backwards. Normally Open means it's open until
the switch is closed. That is the one you might use for an alarm.
The Normally Closed one is one you could put in series with one of the
thermostat wires to prevent system operation when the pan is full and
the pump quit working. You can choose to stop the entir system from
running or to prevent just the compressor from running. Your choice.
Make sure you label it so the next guy isn't outside trying to figure
out why the compressor quit.