On 5/26/2011 3:49 PM, RBM wrote:
wrote in message
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On 5/25/2011 5:24 PM, RBM wrote:
wrote in message
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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
Well this would be fine if there were two wires but how do you put two
wires that are together into a series circuit. Really need someone with
first hand knowledge of this particular pump/wiring.
Not rocket science here. Take the two screws out, lift the cover, you'll see
the two wires are connected to a micro switch with 3 terminals. Common,
NO-NC. Attach the two wires to the common and NC terminals, then wire those
two leads in series with the other limit switch
The conclusion ... I hope!
First, thanks for all the suggestions, many of which were on the mark.
Took the pump/tank off today (I'm an expert at it), disconnected the low
voltage wires which were hooked together, hooked up the ohm meter and
raised the float ... opened the low voltage circuit (thus when assembled
shutting off the heat pump on high water level in the tank). Concluded
that when installed the HVAC guys did not want to bother with the high
reservoir shut down allowing the pan water level sensor to open the HVAC
circuit. Put everything in series (high water level, pan water sensor
and thermostat) left pump unplugged and when water level rose, it shut
the system down. Cool now.
Perhaps when I first observed the problem the high water level was due
to a dirty check valve in the overhead drain coupled with the power
company securing the system remotely and then faulty pump control
switch. Three things at the same time ... improbable, but I know the
check vave was dirty and the pump control switch was hanging up.
$40 for a new $12 switch on a rush delivery while I cleaned the existing
satisfactorily in WD 40. # hours of labor in positions I should not be in.
Again thanks for the informed thoughts.