Rainman Technology Pty Ltd
49 Orchard Road
Brookvale, NSW 2100
Australia
www.rainmandesal.com
support@rainmandesal.com
Introduction
In rare cases, a Rainman electric pressure supply unit (PSU) may fail to start, trip a generator that previously powered it without issue, or draw noticeably more current than normal. These symptoms are most often linked to maintenance issues, with the solution typically being as simple as replacing the rubber impeller or the motor capacitor set.
However, a small percentage of situations are caused by damaged components or seemingly unrelated incidents. This manual explains how to determine whether the rotor of the Rainman PSU motor is jammed and, if it is, how to isolate the location of the problem.
Video Tutorial
Learn how to check for a jammed rotor and identify whether the problem is a mechanical fault on motor or lift pump.
Step by Step Procedure
Before starting, ensure the power supply unit is unplugged from power and the high pressure outlet hose is not connected.
- Unscrew the three fasteners on the lift pump cover using a 7 mm socket.
- Carefully remove the impeller using needle nose pliers if needed.
- Check if the shaft can be manually rotated and observe resistance:
- If it rotates with minimal resistance, the motor’s rotor is not jammed. Stop here and do not proceed further.
- If it feels stuck, continue to next step.
- Undo the two fasteners securing the lift pump using a Phillips screwdriver.
- Carefully separate the lift pump from the motor assembly by pulling straight out along the shaft. Do not lose the shaft key.
- Try to spin the pump shaft by hand.
With the rubber impeller removed the pump should spin with only slight resistance.
- By spinning the fan on the motor’s back, check for rotation resistance.
You should be able to spin it with just a finger, movement should be smooth with no rough spots.
For correct performance motor and pump must be easy to spin.
If you experience any difficulty with either unit spinning, please contact your local Rainman dealer or log a support query with Rainman.