Grundfos MQ 3-35 Service Manual

Service instructions
MQ 3-35, MQ 3-45
50/60 Hz
1~
1 / 24
28.04.2003
GB
Contents
1. Type identification ..........................................................................................................................................................2
1.1 Nameplate.........................................................................................................................................................................2
1.2 Type key .............................................................................................................................................................................3
2. Service tools ..................................................................................................................................................................... 4
2.1 Special tools ..................................................................................................................................................................... 4
2.2 Standard tools ................................................................................................................................................................. 4
3. Dismantling and assembly............................................................................................................................................5
3.1 General information .......................................................................................................................................................5
3.2 Replacing the shaft seal, chambers and impellers................................................................................................. 6
3.3 Replacing the pressure tank ........................................................................................................................................ 8
3.4 Replacing the electronic unit, flow sensor and pressure switch ........................................................................ 9
3.5 Replacing the motor unit............................................................................................................................................ 10
4. Operation.........................................................................................................................................................................11
4.1 Priming .............................................................................................................................................................................11
4.2 Start...................................................................................................................................................................................11
4.3 Stop ...................................................................................................................................................................................11
4.4 Alarm ................................................................................................................................................................................11
4.5 Auto-reset........................................................................................................................................................................11
4.6 Manual reset...................................................................................................................................................................11
4.7 Control panel ..................................................................................................................................................................12
4.8 Overview..........................................................................................................................................................................13
4.9 Fault finding....................................................................................................................................................................14
4.10 Fault finding overview .................................................................................................................................................15
5. Wiring diagram ............................................................................................................................................................. 24
5.1 Winding resistence measurement........................................................................................................................... 24

Grundfos MQ 3-35 Specifications

General

Power Consumption	850 W
Maximum Head	35 m
Inlet/Outlet Size	1 inch
Weight	13 kg
Pump Type	Self-priming centrifugal pump
Power Supply	220-240V, 50Hz
Liquid Temperature Range	0°C to +35°C
Material	Stainless steel

Summary

Type Identification

Nameplate

Details the components and specifications listed on the pump's nameplate.

Type Key

Explains the coding system used to identify different pump models and their features.

Service Tools

Special Tools

Lists and describes specialized tools required for pump maintenance and repair.

Standard Tools

Lists common tools needed for pump servicing and their specifications.

Dismantling and Assembly

General Information

Provides introductory guidance on referencing parts, tools, and preparation before disassembly.

Before Dismantling

Outlines essential safety steps and procedures before starting the pump disassembly process.

Before Assembly

Details critical steps and recommendations for preparing parts before reassembling the pump.

Replacing the Shaft Seal, Chambers and Impellers

Step-by-step instructions for safely removing and fitting the shaft seal, chambers, and impellers.

Replacing the Pressure Tank

Detailed instructions for removing and fitting the pressure tank.

Replacing the Electronic Unit, Flow Sensor and Pressure Switch

Procedures for replacing electronic components like the unit, flow sensor, and pressure switch.

Replacing the Motor Unit

Step-by-step guide for removing and installing the motor unit.

Operation

Priming

Instructions on how to fill the pump with water before initial start-up to remove air.

Start

Conditions and procedures for starting the pump operation.

Stop

Conditions under which the pump will automatically stop operating.

Alarm

Explains the conditions that trigger an alarm and cause the pump to stop.

Auto-reset

Describes the automatic restart function after an alarm condition.

Manual Reset

Methods for manually resetting the pump after an alarm or fault.

Control Panel

Details the function of indicator lights, buttons, and their roles in pump operation and status.

Overview

Provides visual identification of key components controlling the pump's function.

Fault Finding

A table listing common faults, their causes, and recommended remedies for troubleshooting.

Fault Finding Overview

A visual guide correlating system reactions with typical faults and their troubleshooting paths.

Wiring Diagram

Winding Resistance Measurement

Provides a table with motor winding resistance values at different voltages and ambient temperatures.