High Pressure Pump Servicing Instructions – Page 12
16.
Reseat the manifold gently pushing it back into place.
Install it straight with minimum wiggle.
17.
Once manifold is properly seated, install head bolts
and begin torque sequence. Tighten to 12 Nm or 8.9
Ft-lbs.
Setting Relief Valve
A relief valve is part of every Rainman watermaker as a safety precaution. It prevents build up of excessive
pressure in the RO system if the control valve is accidentally closed too far. If the system does get over
pressured, the relief valve opens and recirculates water through the pump to ensure no damage or high
pressure leaks occur.
In normal use the relief valve remains closed at all times. If the pressure reaches approximately 62 bar (900
psi) the valve starts to open, returning some water to the intake side of the system. At approximately 69 bar
(1000 psi) it will be completely open, limiting the maximum output pressure of the PSU to approximately 69
bar (1000 psi). All relief valves are set in the Rainman factory during final testing of each system. In the highly
unlikely event that a relief valve needs to be replaced, it will need to be set to the correct opening pressure.
This section describes the procedure for setting the correct opening pressure, using the pressure gauge on
any of the Rainman RO systems. It should be emphasised that it is highly unlikely you will ever need to
replace or adjust the relief valve.
All petrol/gasoline systems and original design, pre-January 2019, Mk1 electric systems utilise the VS100
relief valve, which is separate to the WM series pump itself. On Mk2 electric systems, manufactured after
February 2019, the WMR pump has an integrated relief valve built into the manifold. You will need to
remove the shell to access the relief valve on all cased electric systems. A separate document exists to
remove the shell on Mk1 electric systems.
Petrol/gasoline PSU WM Pump Mk1 Electric PSU WM Pump Mk2 Electric PSU WMR Pump