"Pointer" wrote in message
...
On 5/25/2011 8:22 AM, wrote:
On May 25, 8:05 am, 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.
Do you have any idea why they have been wired together all this time? By
the way I do not use the alarm but want only the high level shut down to
work. Also it would seem to me that I would use the NC switch in series
for it would open on high water and shut the unit down. The pan overflow
switch is separate from the pump and is definitely in series.

**I would guess that they assumed the one limit switch would be sufficient.
Just wire it in series the pan switch