Setting The Pwm Input Signal; Servicing The Product; Dismantling The Product; Dismantling The Plug - Grundfos ALPHA1 L Serie Instrucciones De Instalación Y Funcionamiento

7.1 Setting the PWM input signal

To enable the external control mode (PWM profile A), you need a
signal cable connected to an external system. The cable connection
has three conductors: the signal input, the signal output and the
signal reference.
Conductor
Signal input
Signal reference
Signal output
The cable is not supplied with the pump but can be ordered as an
accessory. The cable length must not exceed 3 metres.
The cable must be connected to the control box via a mini
superseal plug. See fig. Mini superseal plug.
Mini superseal plug
Set the signal connection
1. Make sure that the pump is turned off.
2. Locate the PWM signal connection on the pump. The three pins
inside the signal connection are not energised.
3. Connect the signal cable with the mini superseal plug.
4. Switch on the power supply.
5. The pump automatically detects if a valid PWM signal is
available after which it enables the control mode on the pump.
See fig. Connecting the signal cable to ALPHA1 L. If the pump
does not detect a PWM signal or if the signal equals 0, the
pump will switch to the control mode selected before connecting
to a PWM signal.
1 x 230 V - 15 %/+ 10 %
∽ 50/60 Hz
Connecting the signal cable to ALPHA1 L
20
Colour
Brown
Blue
Black

8. Servicing the product

DANGER
Electric shock
Death or serious personal injury
‐
All electrical connections must be carried out by a
qualified electrician in accordance with local regula-
tions.
DANGER
Electric shock
Death or serious personal injury
‐
Switch off the power supply before starting any work
on the product. Make sure that the power supply can-
not be accidentally switched on.
CAUTION
Hot surface
Minor or moderate personal injury
‐
The pump housing may be hot due to the pumped liq-

uid being scalding hot. Close the isolating valves on

both sides of the pump and wait for the pump housing

to cool down.

CAUTION
Pressurised system
Minor or moderate personal injury
‐
Before dismantling the pump, drain the system or

close the isolating valves on both sides of the pump.

The pumped liquid may be scalding hot and under

high pressure.

All service must be carried out by an instructed service
technician.

8.1 Dismantling the product

1. Switch off the power supply.
2. Pull out the plug. For instructions on how to dismantle the plug,
see section Dismantling the plug.
3. Close the two isolating valves on both sides of the pump.
4. Loosen the fittings.
5. Remove the pump from the system.
Related information
8.2 Dismantling the plug

8.2 Dismantling the plug

1. Loosen the cable gland and unscrew the union nut in the centre
of the terminal cover.
2. Detach the terminal cover.
3. Loosen the screws on the power supply plug and disconnect the
cable conductors.
4. Pull the power cable back through the cable gland and terminal
cover.