A pump on its own runs when you switch it on. To have water arrive when you open a tap, something must start and stop it automatically. There are two established ways to do that, and the choice shapes how the whole system behaves.
Method 1: Pressure switch and tank
The traditional arrangement. A pressure switch watches system pressure and a pressure tank stores water under pressure.
- Pressure falls to the cut-in point → pump starts.
- Pressure rises to the cut-out point → pump stops.
With Rural Max tanks pre-charged to 2 bar, the switch is set to cut in just above that — around 2.2 bar — and cut out around 4.0 bar.
- Small draws come from the tank without the pump running at all.
Pressure varies as you use it. The shower is stronger just after the pump cuts out and weaker just before it cuts in. That swing is the system working normally.
Method 2: Electronic pump controller
A controller replaces both switch and tank with a single device that senses flow as well as pressure.
- Open a tap → pressure drops below the controller’s threshold → pump starts.
- Close the tap → flow stops → the controller waits a few seconds, then stops the pump.
- No tank required, and pressure stays essentially constant while water is flowing.
Rural Max controllers are pre-set at 1.5 bar with no adjustment to make — they are wired in-line and simply work. Both models carry an IP65 rating for outdoor use and include run-dry protection, which shuts the pump down if it loses water rather than letting it destroy its seal.
| RMPC-10 | RMPC-30 | |
|---|---|---|
| Max rated current | 10 A | 30 A |
| Maximum pump size | 1.1 kW | 3 HP / 2.2 kW |
| Pre-set pressure | 1.5 bar | 1.5 bar |
| Max allowable pressure | 10 bar | 10 bar |
| Inlet / outlet | 1” | 1” |
| Supply | 220 V, 50 Hz | 220 V, 50 Hz |
| Max ambient temperature | 40 °C | 40 °C |
| Max liquid temperature | 60 °C | 60 °C |
| Protection | IP65 | IP65 |
Matching a controller to your pump
The controller must be rated at or above the pump’s power draw. Undersizing burns out the controller’s relay.
| Pump | Power | Suitable controller |
|---|---|---|
| RM-JP100 | 750 W | RMPC-10 |
| RM-SJP800 | 800 W | RMPC-10 |
| RM-JP200 | 2 HP (1.5 kW) | RMPC-30 |
| RM-DJSM1025 | 2 HP (1.5 kW) | RMPC-30 |
| RM-TF1 | 1 HP (0.75 kW) | RMPC-10 |
Anything above 1.1 kW needs the RMPC-30. If a pump sits close to the boundary, size up.
Note that the RM-JP100-E and RM-SJP800-E already have automatic pressure control fitted — no separate controller needed.
Comparing the two
| Pressure switch + tank | Electronic controller | |
|---|---|---|
| Pressure at the tap | Varies between cut-in and cut-out | Essentially constant |
| Space needed | Significant — tank is bulky | Minimal, mounts on the pump |
| Pump starts per day | Fewer, tank absorbs small draws | More, one per draw |
| Small draws | Handled by the tank, pump stays off | Pump runs briefly every time |
| Run-dry protection | Requires a separate device | Built in |
| Setup | Pre-charge set to 2 bar, checked twice a year | None, pre-set at 1.5 bar |
| Ongoing maintenance | Check pre-charge twice a year | Effectively none |
| Failure mode | Diaphragm ruptures, tank waterlogs | Electronic failure stops the pump |
| Cost | Tank + switch + fittings | Single unit |
The real trade-off
A controller gives better pressure but more pump starts. Every hand wash starts the pump for a few seconds. Motors are stressed by starting, so on a system with many small draws a controller works the pump harder than a well-sized tank does.
A tank gives fewer starts but variable pressure, needs space, and needs its pre-charge checked. As covered in Pressure Tanks Explained, a tank large enough to give a full minute of pump run time is bigger than most people expect.
Using both together
For a house on tank water this is often the best answer: a controller for constant pressure and run-dry protection, plus a modest pressure tank to absorb small draws so the pump does not start for every hand wash.
A RM-R18 or RM-R60 alongside an RMPC controller smooths pressure and absorbs water hammer while the controller handles start/stop and run-dry protection.
Be aware of how the two interact. Rural Max tanks are pre-charged to 2 bar, while the RMPC controllers start the pump at a fixed 1.5 bar. Because the controller restarts the pump before system pressure falls to the tank’s pre-charge, the tank never begins to discharge — so in this combination it works as a pressure cushion and hammer arrestor, not as a store of usable water, and it will not reduce the number of pump starts.
To get genuine drawdown from a tank you need a pressure switch set to cut in above 2 bar — typically 2.2 bar cut-in and 4.0 bar cut-out — rather than a fixed 1.5 bar controller.
Choosing
Choose a controller when:
- Constant pressure matters — showers, modern tapware, filtration systems.
- Space is tight.
- You want run-dry protection without a separate device.
- You would rather not maintain a pre-charge.
- The pump feeds a small number of outlets used deliberately, not constantly.
Choose a pressure switch and tank when:
- Minimising pump starts is the priority.
- The system has many small, frequent draws.
- The pump is large or expensive and you want it working as little as possible.
- You already have a tank installed and working.
Choose both when:
- It is a household water supply and you want it to behave like mains water.
Installation notes
- Controllers mount on the discharge side, directly at the pump outlet where possible, with the flow arrow pointing away from the pump.
- Mount them upright unless the instructions say otherwise — internal flow sensing depends on orientation.
- IP65 handles rain and dust, but shelter from direct sun anyway. Heat shortens electronics life.
- Electrical connection must comply with AS/NZS 3000. Plug-connected installations go on an RCD-protected outdoor-rated circuit; anything hard-wired needs a licensed electrician.
- After fitting, test the run-dry function: with the pump running, close the supply valve and confirm the controller shuts the pump down rather than letting it run dry.
Once it is in, work through the commissioning checks in Installing a Domestic Pressure Pump.
