Vacuum Limiting Valve; Pump Thermal Fuse; Optional: Compressed Air Switch; Before Installation - Nederma RBU Serie Manual De Instrucciones

13. Two lead cable to solenoid V1 on the universal valve, see also Figure 4. This cable can be
combined with the cable to the thermal fuse, item 12, into a single four lead cable.
14. Optional: Maintenance switch. This is required in most countries.
15. Vacuum meter. The meter is linked to the vacuum unit nipple by a 6 mm (1/4") tubing. The
meter is supplied with the unit.
16. Motor cooling air outlet without any connections. The inlet must always be kept free to
prevent overheating.
17. Ventilation opening with noise trap without any connections. The opening must always be
kept free to prevent overheating.
18. Vacuum unit.
5.2

Vacuum limiting valve

Figure 4 shows the control of the vacuum limiting valve. The solenoid valve V1 is connected
through an auxiliary switch on the D-contactor. The valve is fully open in Y-mode and no
vacuum is produced. This ensures that the unit is idling during start up. The valve closes at
switch over into D-mode and the unit starts to produce vacuum. The valve is never fully closed.
5.3

Pump thermal fuse

Figure 5 shows the circuit diagram for the overheating cut-out on the pump. The circuit trips and
stops the unit when the temperature reaches 140 °C (284 °F).
NOTE!
The circuitry in the start and control unit must on no account allow the unit to re-start
directly when the thermal fuse is replaced. Instead, manual reset of a circuit in the start and
control unit must be required. Voltage must not exceed 24V.
Thermal tripping is to be indicated by a lamp or LED. The manufacturer of the motor start and
control unit is responsible for supplying a reliable circuit for this purpose.
5.4

Optional: Compressed air switch

An optional compressed air switch can be mounted in the vacuum unit to prevent it from starting
with no compressed air supply. No air supply must result in an error indication in the start and
control unit. For electrical connections, see Figure 5 and the start and control unit's manual.
The compressed air switch is wired in series with the thermal fuse. Use a jumper to connect the
terminals if no compressed air switch is used.
6

Before installation

6.1

Delivery check

Check the RBU unit for any transport damages. In case of damage or parts missing, notify the
carrier and your local Nederman representative immediately. It is recommended to transport the
RBU unit to the installation site while still in the factory packing.
All manuals and user guides at all-guides.com
RBU EN
15