Home & Garden Swimming Pools & Water Fountains & Ponds

How to Determine What is Wrong With a Pump

This article applies to Balboa VS501 or VS520 spa packs and may be different for other spa packs.
Difficulty= Medium   Answer: When power is applied to the spa pack it goes into a power up sequence.
  After the - - appears on the panel, the pump should start to run in low speed.
If no flow  is produced (and it isn't a simple problem like a plugged filter or suction screen, closed valve) the problem is either:   a) The spa pack receptacle into which the pump is plugged does not produce 230 or 120  volts ac, or b) 230 or 120 volts is available at the pump motor terminals but the pump motor does not rotate or c) 230 or 120 volts is available at the pump motor terminals and the motor rotates normally but the pump is not producing any flow.
When tracing a pump problem you want to disconnect one terminal of the heater element.
  Use two 3/8" wrenches to do so, so that you don't twist off the element wire.
  Above it states 230 or 120 volts.
Which one applies depends on the pump motor installed and it depends on the W1 white wire jumper.
  If this wire is attached to a RED AC terminal the voltage should be 230 volts.
  If attached to a WHT AC terminal the voltage should be 120 Volts.
  This is under the assumption that 230 volt service is being used.
  If the service is only 120 volts then the voltage available is only 120 volts.
To check if  the problem is a) requires the use of an AC Voltmeter.
  Once the power-on sequence is at or past the - - indication, insert the voltmeter leads into J23 (Pump1 receptacle).
  They should be plugged into two middle pins.
(2nd from bottom is common and the pin one up is low speed and top pin is high speed).
  If the circuit board is functioning, then you'll get 230  or 120 volts here.
  If you do not get any voltage and you are sure service power is coming to the main terminals on the circuit board, then the problem lies either with the large fuse in the upper right hand corner of the circuit board or the circuit board itself is defective.
   If the fuse is shot (open circuited) then you will measure 120 volts (from the neutral terminal) to its left side but 0 volts on the right side.
A fuse will blow for a reason, such as shorted motor or a jammed pump.
  Investigate this first before trying another fuse.
See if you can spin the pump using a screw driver and inserting it into the slot at the back of the motor shaft with the cord unplugged.
If the fuse is okay and the voltage is not appearing on J23, then the circuit board needs replacement.
  The check for b) is to open the motor connection cover and test for 230 or 120 volts at the terminals where the white and black wires from the cable are attached.
  If a) above checked out (you did have 230 or 120 volts at the circuit board's J23 receptacle), then there should also be 230 or 120 volts at the motor terminals.
If not there is something wrong with the cable or its connector(s).
  If there is 230 or 120 volts at the motor terminals and the motor is humming or turning very slowly, the low speed start capacitor is likely gone.
  If the motor is not spinning and there is very little or no noise, the motor is likely burned out or has an open circuit.
  In either case the motor then needs to be replaced or repaired.
  The check for c) we describe will also check that there is water in the pump and piping.
  Attach a hose to the hose bib.
  Close the globe valve that is located after the outlet of the filter.
  Open the hose bib valve so water flows out of the hose.
  This confirms that water is in the pump and in the piping.
Now raise the hose to the same level as the water line of the hot tub.
  At this point it will stop flowing.
  Turn on the power and wait for the pump motor to start turning.
  If water then doesn't flow out of the hose, at a significant rate,  the impeller isn't turning properly, either because it's jammed or because the plastic impeller shaft has sheered off.
  In either case the wet end needs replacing or repairing.

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