In order to fully understand the operatIon of these pumps,
It Is necessary to understand some of theIr basIc prIncIples
of operatIon:
All minisplit piston pumps share some common characteristics:
1. they are self priming.
2. they are water cooled.
3. they are water lubricated.
This means that when they are activated, they will self prime, however during this initial period they
will draw in air and while this is happening they will be running both hot and dry.
Because of this,
they will emit a clicking noise which is entirely normal during the initial start
up phase only,
(usually around 10 seconds or less) and this will stop when all of the air in the pump
intake has been purged and the pump becomes cooled and lubricated by the water flowing through
it.
IF THE CLICKING NOISE IS HEARD WHILE THE PUMP IS OPERATING AFTER THE INITIAL
START UP HAS BEEN COMPLETED, THIS IS AN ABNORMAL SITUATION WHICH INDICATES
THAT THERE IS A PROBLEM AND THE PUMP IS RUNNING WITHOUT COOLING OR
LUBRICATION AND IS OVERHEATING.
This usually occurs in a split pump because the intake hose (¼” clear vinyl hose between the reser-
voir and the pump) has emptied itself due to a siphoning effect created by atmospheric pressure.
THEREFORE IT IS VITAL THAT THE INTAKE HOSE IS KEPT FULL OF WATER AT ALL TIMES SO
THAT NO AIR IS PRESENT FOR THE PUMP TO DRAW IN WHEN IT STARTS OPERATING.
AS LONG AS THE INTAKE HOSE REMAINS FULL OF WATER, EVERY TIME THE PUMP STARTS
UP IT IS IMMEDIATELY COOLED AND LUBRICATED BY THE WATER FLOWING THROUGH IT
AND WILL OPERATE AS DESIGNED, WITH MINIMAL NOISE.
EACH PUMP IS FITTED WITH A THERMAL OVERLOAD PROTECTOR WHICH WILL DEACTIVATE
IT IN CASE OF OVERHEATING, HOWEVER, ONCE IT COOLS DOWN IT WILL BEGIN TO OPER-
ATE AGAIN, AND IF THE PUMP IS ALLOWED TO CONTINUE TO OPERATE FOR A SUSTAINED
PERIOD OF TIME IN THIS CONDITION, IT WILL FAIL.
In some applications, the vertical distance between the reservoir and the pump can be up to 6 feet
and the longer this distance, the longer the pump will have to operate hot and dry before it evacuates
the air from the intake tube and, therefore, the longer time it will have in which to damage itself.
If the end of the discharge hose is lower than the level of the drain pain in the evaporator, the weight
of the water in the discharge hose plus atmospheric pressure on the water in the drain pan will cause
the water to continue flowing,
EVEN AFTER THE PUMP HAS SWITCHED ITSELF OFF,
until all the
water in the system has evacuated itself.
Important note:
USING DISCHARGE HOSE OTHER THAN THE SIZE SPECIFIED (¼” ID)
MAY RESULT IN REDUCED PERFORMANCE.
Guidelines for Installation of Discharge Hosing
17
