DIVEX MHE-02 Installation guide

KI-OM-776 R1
INSTALLATION, OPERATING AND
MAINTENANCE MANUAL
for the
Mini Water Heater Electric
Model: MHE-02
(380 VAC Supply x 24 VDC Controls)
Document No: KI-OM-776
Legacy No: 06360-805
(Part No: KI40026AB)

(Intentionally Blank)

i
KI-OM-776 R1 Approval Sheet
APPROVAL SHEET
DIVEX
DOCUMENT NUMBER: KI-OM-776
LEGACY NUMBER: 06360-805
DOCUMENT TITLE: Installation, Operating and Maintenance Manual - MHE-02, 380
VAC Supply x 24 VDC Controls
REV DATE BY CHECK APP COMMENTS
0 13/04/2010 R. Carli N. Maske R. Faustmann First Issue
1 26/10/2012 V. Garzon N. Maske M. Stevens ECN: 15089
2
3
4
5
6
7
ORIGINAL ISSUE DATE: 13 April 2010
ORIGINAL DOCUMENT BY: Roy Carli
CHECKED BY: Nicholas Maske
APPROVED BY: Rainer Faustmann

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Approval Sheet KI-OM-776 R1
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iii
KI-OM-776 R1 Table of Contents
II Data Sheet ............................................................................................................................. v
III Disclaimer .............................................................................................................................vii
IV Confidential Information ........................................................................................................ ix
V Warranty ................................................................................................................................ xi
VI List of Tables and Figures ....................................................................................................xiii
CHAPTER 1 - GENERAL DESCRIPTION ..................................................................................... 1
1.1 Introduction ....................................................................................................................... 1
1.1.1 Basic Description .............................................................................................................. 1
1.2 Specifications ................................................................................................................... 1
1.3 Theory of Operation .......................................................................................................... 2
1.3.1 Basic Control .................................................................................................................... 2
1.3.2 Fluid System ..................................................................................................................... 3
1.3.3 Electrical System Overview ..............................................................................................5
1.3.4 Electrical System Detail (Control Logic and Component Identification) ........................... 5
1.3.5 Heater System and Heater Selection ............................................................................... 6
1.3.6 Control System ................................................................................................................. 7
CHAPTER 2 - INITIAL SET UP .................................................................................................... 11
2.1 Installation ...................................................................................................................... 11
2.1.1 General Mounting and Unit Placement ........................................................................... 11
2.1.2 Fluid Connections ........................................................................................................... 11
2.1.3 Electrical Installation ....................................................................................................... 12
2.2 Initial System Check .......................................................................................................13
2.2.1 Fluid System Priming Procedure ....................................................................................13
2.2.2 Start Up and Function Check ......................................................................................... 14
CHAPTER 3 - OPERATION ......................................................................................................... 17
3.1 General ........................................................................................................................... 17
3.1.1 Operator Controls ........................................................................................................... 20
3.1.2 Operating Start-Up Procedure ........................................................................................21
3.1.3 Shutdown Procedure ......................................................................................................22
CHAPTER 4 - MAINTENANCE .................................................................................................... 23
4.1 Routine Maintenance ...................................................................................................... 23
4.1.1 Periodic Maintenance .....................................................................................................23
TABLE OF CONTENTS

iv
Table of Contents KI-OM-776 R1
4.2 Pump Maintenance ......................................................................................................... 24
4.2.1 Helpful Information ......................................................................................................... 24
4.2.2 Pump Specifications ....................................................................................................... 25
CHAPTER 5 - TROUBLESHOOTING .......................................................................................... 27
5.1 Pump Specific Fault Diagnosis and Maintenance .......................................................... 27
5.2 General Troubleshooting Chart ......................................................................................29
APPENDIX A - PART IDENTIFICATION ...................................................................................... 35
APPENDIX B - RECOMMENDED SPARE PARTS LIST ............................................................. 39
APPENDIX C - WIRING DIAGRAMS ........................................................................................... 41
APPENDIX D - PIPING AND FLOW SCHEMATIC ....................................................................... 42
APPENDIX E - RKC CB100 DIGITAL CONTROLLER MANUAL .................................................43
APPENDIX F - BELIMO CONTROL VALVE MANUAL ................................................................. 44
APPENDIX G - WATER PRESSURE REDUCING VALVE .......................................................... 45
APPENDIX H - CAT TRIPLEX PUMP - MANUAL - MODEL 1050 ...............................................46
APPENDIX I - PULSATION DAMPENER ..................................................................................... 47
APPENDIX J - PRESSURE REGULATOR ................................................................................... 48
APPENDIX K - FLOW SWITCH .................................................................................................... 49

06804-805 v
KI-OM-591 Rev 2 Datasheet
II. DATASHEET
Instruction and Maintenance Manual
No: 06804-805
Equipment Type: Water Heater Electric with Remote
Control - WHE-3 (440V x 24V)
Equipment Serial No:
Customer:
Vessel / Location:
(if known)
Date of Issue:
IMPORTANT
Please quote the above information when contacting Divex regarding
operational information or spare parts.

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Data Sheet KI-OM-776 R1
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vii
KI-OM-776 R1 Disclaimer
III. DISCLAIMER
Whilst every effort has been made to ensure the accuracy of the information provided in this
document, Divex makes no guarantees therefore.
Misuse of the equipment described in this manual could result in injury. It is the responsibility
of the user to ensure that the equipment is used and maintained correctly and in accordance
with the instructions provided in this manual in order to ensure safety of life and to prevent
injury.

viii
Disclaimer KI-OM-776 R1
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ix
KI-OM-776 R1 Confidential Information
IV. CONFIDENTIAL INFORMATION
This document is confidential and is the property of Divex It may not be distributed to
persons or organizations other than the intended recipient without the prior written consent of
the owner.

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Confidential Information KI-OM-776 R1
(Intentionally Blank)

xi
KI-OM-776 R1 Warranty
V. WARRANTY
Divex Ltd warrants that its Mini Water Heater Electric (Type MHE-02), conforms to the
current product specification at the date of delivery and that the product will be free of patent
defects in materials or workmanship for a period of twelve months from the date of delivery
or for the first 3,000 operating hours, whichever occurs first.
Any component or sub-system which is established by Divex to be patently defective will, at
Divex’s option, be repaired or replaced on condition that such defective equipment is
returned to Divex’s manufacturing facility in Cape Town, South Africa, freight pre-paid. On
completion of any repair or replacement, the equipment will be returned to the customer FOB
Cape Town, South Africa. By agreement and upon prepayment by the customer of any
transportation, on-site accommodation and subsistence expenses, Divex may dispatch
personnel to perform on-site repairs.
The product specification and warranty terms are subject to alteration without prior notice
and do not form part of any contract made between Divex and its customer.
This equipment should only be operated by suitably qualified persons conversant with the
operation and maintenance of diver hot water systems. Before operating the equipment, the
user must be fully acquainted with the instructions contained in this manual, as well as the
individual component manufacturer’s operating and maintenance information provided in the
Appendixes.
Only genuine manufacturer's spare parts may be used in this Divex product. Use of other
manufacturer’s parts may cause degradation of performance or failure and will invalidate the
warranty.
The following information is required by Divex when ordering spare parts:
• Customer’s / owner’s name
• Equipment serial number
• Spare part type / description
• Part number

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Warranty KI-OM-776 R1
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xiii
KI-OM-776 R1 List of Tables and Figures
VI. LIST OF TABLES AND FIGURES
Fig 1.1 MHE-02 Fluid Connections ..........................................................................................4
Fig 1.2 Control Panel Layout ....................................................................................................7
Fig 2.1 Controller Display .......................................................................................................15
Fig 3.1 Graph of Temperature Loss vs. Umbilical Length ......................................................18
Fig 3.2 General Arrangement .................................................................................................20
Fig A.1 MHE-02 General Arrangement - Isometric View ........................................................35
Fig A.2 MHE-02 General Arrangement - Side View ...............................................................36
Fig A.3 MHE-02 General Arrangement – Front View .............................................................38
Table 1.1 Heater Component Identification ..................................................................................6
Table 1.2 Control component identification ................................................................................10
Table 3.1 Heater Selection Table for Required Temperature Rise ............................................19

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List of Tables and Figures KI-OM-776 R1
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1
KI-OM-776 R1 Chapter 1
CHAPTER 1 GENERAL DESCRIPTION
1.1 INTRODUCTION
The Divex Electric Powered Mini Water Heating Module, (MHE-02), has been designed for
use in professional diving systems. The system will heat sea water and control the heated
sea water within a temperature rise range of 0 to 42ºC (0 to 74ºF). The system incorporates
a positive displacement pump, electric heaters and all electrical controls necessary to
provide a complete water heating system for deep diving.
1.1.1 BASIC DESCRIPTION
The MHE-02 assembly Includes a motor, pump, heater tank, pipework and a control panel.
These components are mounted into a robust stainless steel frame. The system requires a
constant supply of sea water and runs from a 380V, 3-phase, 50 Hz power supply. The
output is heated sea water at pressures up to 68 bar and 30 litres/min.
1.2 SPECIFICATIONS
Shipping Weight 385 kg
Dry Weight 315 kg
Power Requirements 380 VAC, 3-phase, 50 Hz, 94.5 kW, 140 A
Input Fluid Fresh Water or Sea Water
Input Pressure 3.4 to 10 bar
Input Flow Rate 30 litres / min minimum
Output Pressure Up to 68 bar
Output Flow 30 litres / min
Temperature Rise Control
Range 0 to 42oC (0 to 74oF)
Temperature Control ± 1ºC (± 2ºF)

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Chapter 1 KI-OM-776 R1
1.3 THEORY OF OPERATION
1.3.1 BASIC CONTROL
The temperature control system of the MHE-02 has been designed to be simple and
effective. The unit heats water in the heater tank using three banks of heater elements.
These heater banks are controlled with three switches, mounted on the electrical enclosure.
The banks of heaters are configured to deliver a variety of heating capacities depending on
the combination of banks selected. When all three heater circuits are on, the total rated
heater output is 94.5 kW. The appropriate heater circuits must be selected manually
according to the relative temperature rise required. A schedule is attached to the front of the
control panel door indicating the heater banks to be used for the required temperature rise.
Example: Heater bank selection for required temperature rise through the MHE
The above example shows that if a bottom temperature of 38ºC is required with a
temperature drop through the hose to the diver of 8ºC and an inlet water temperature of
10ºC. The temperature required at outlet from the MHE would be 46ºC. The required
temperature rise through the unit would be 36ºC. The heater selection table shown in Table
3.1 indicates that heater banks 1, 2 and 3 should be used for the required temperature rise
through the unit.
Once the correct configuration of heater banks has been selected and the required setpoint
entered into the temperature controller, the controller will regulate the temperature of the
outlet by adjusting the flow rate of water through the heater tank. This is achieved by
controlling the electric actuator on the bypass valve. The valve is connected in such a way
that it will dump a proportion of the heated water overboard thereby increasing the flow rate
through the heater tank. A higher flow rate through the heater reduces effective temperature
rise and maintains the desired set point temperature at the outlet. The temperature controller
monitors the temperature at the fluid outlet manifold using a PT100 temperature sensor and
adjusts the control valve position to achieve the set point temperature.
Td- Required outlet water temperature, at diver = 38ºC
TΔh- Temperature drop (Hose from deck to diver = 8ºC
Ti- MHE Inlet water temperature is = 10ºC
To- MHE Required outlet water temperature = (Td+ TΔh)
- = (38 + 8)ºC
-=46ºC
ΔT - Required temperature rise through the MHE = (To- Ti)
- = (46 – 10)ºC
-=36ºC (Use heater banks 1, 2 and
3)

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KI-OM-776 R1 Chapter 1
1.3.2 FLUID SYSTEM
The MHE-02 may function with either salt water or fresh water as the heating medium. The
unit is provided with two inlets for fluid, one for fresh water and one for sea water. The fresh
water line is typically used for flushing the system after use. The freshwater line is fitted with
a check valve to prevent salt water contamination of the fresh water supply. The unit uses
small inexpensive immersion heater elements mounted in the flange plate of the stainless
steel heater tank to heat the fluid. The flow rate of the fluid through the heating tank is
governed by the action of the bypass valve.
The flow rate of fluid from the heater tank to the divers is determined by the motor speed and
the ratio of the pulley set used to couple the motor to the pump. The pump is a positive
displacement pump and is designed and supplied with a pulley arrangement to provide a
flow rate of 30 litres/min.
The fluid to be heated enters the unit at the assigned inlet and flows through a manifold and
a quarter-turn hand valve. The manifold is equipped with analogue temperature and
pressure gauges to provide operator feedback on the fluid supply. The fluid is then piped to
two separate inlet filters. The two filters may be isolated using hand valves on the inlet and
outlet of each filter. Only one filter should be used under normal operation with the other on
standby and ready to be put into operation. These filters clean input water of particulate
matter down to 50µm in order to protect the piston pump and umbilical coupling from being
damaged and prevent clogging of the heating water tubes in the diver suits. The inlet filters
are each fitted with pressure gauges in order to monitor pressure drop across the filter and
indicate the condition of the filter cartridge. A pressure regulating valve fitted after the filter
IMPORTANT
The calculated required temperature rise may be indicated on the heater bank
selection schedule as a maximum for one configuration and a minimum on the
subsequent selection of heater banks. In this case practical application will dictate
which configuration should be used. The higher capacity configuration is usually
used to allow for better control.
If the bypass dump valve remains fully open during normal operation, indicating
heating over-capacity then the lower kW heater configuration should be used to
improve control and unit performance.
If the bypass valve remains fully closed during normal operation, indicating heating
under-capacity or a possible heater bank fault then a higher kW configuration
should be used to improve control.
IMPORTANT
Fluid supply to the unit by the vessel must be maintained above 30 litres/min at 3
bar for correct operation.

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Chapter 1 KI-OM-776 R1
outlet ensures that fluid is supplied from filters to heater tank at a consistent and safe
pressure.
The fluid flows through the heater tank which houses immersion heater elements where fluid
is heated. A float switch housed in the level control tank mounted on top of the heater tank is
used to ensure the heater elements and pump are not run without sufficient supply. If the
level in the tank drops the level switch shuts down the system. From the level control tank,
the fluid is distributed to the temperature control valve, manual temperature control valve and
pump. The manual control valve controls the process in the same way as the automatic
control valve and is provided to control outlet temperature if automatic control is inactive. The
pump supply is directly coupled to the level control tank.
The pump is a positive displacement pump and provides consistent supply flow rate. An
accumulator is fitted to reduce the effect of pulsation caused by the pump. The fluid from the
pump flows through a pressure relief valve which may be set between 7-70 bar and is
sufficiently sized to allow full flow bypass if a downstream blockage occurs. During normal
operation, the hot water flows through a flexible reinforced hose to the outlet via the outlet
manifold. The outlet manifold is fitted with both pressure and temperature gauges to provide
operator feedback.
A full flow diagram and system drawings are provided in the Appendix.
Fig 1.1 MHE-02 Fluid Connections