MHS Boilers Ultramax WM 45 Installation and operation manual

Ultramax WM Wall Mounted Condensing Boiler
Operating & Maintenance Manual
For Models 45, 65, 85, 100 & 120
MHS Boilers Ltd
3 Juniper West
Fenton Way
Basildon Essex
SS15 6SJ
01268 546700 Telephone [phone] Fax
WWW.MHSBOILERS.COM
L282

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Contents
Section Page #
WM Technical data 4
WM Dimensions 5
1 1 Introduction 6
1.1 General 6
1.2 The supplier 6
1.3 This document 6
1.4 Service 7
1.5 General restrictions 7
2 Description 7
2.1 General 7
2.2 Main components 9
2.21 Case Removal 9
2.2.2 Description of principal components 10
2.3 Boiler control 11
2.4 Safety aspects 11
3 Safety 12
4 Delivery and transport 13
4.1 Delivery 13
4.2 Packaging 13
4.3 Transport 13
5 Installation 14
5.1 Regulations 14
5.2 Installation area 14
5.2.1 General 14
5.2.2 Installation 14
5.2.3 Ventilation 14
5.3 Connections 15
5.3.1 Gas connection 15
5.3.2 Electrical connections 15
5.3.3 Water connections 26
5.3.4 Flue gas outlet and air inlet 26
5.3.4.1 Connection possibilities 26
5.3.4.2 Air inlet pipe 27
5.3.4.3 Flue gas outlet 27
5.3.4.4 Flue 28
5.3.5 Condensate drain 30
5.4 Hydraulic system 30

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5.4.1 Water flow 30
5.4.1.1 Flow and resistance 30
5.4.1.2 Pump characteristics 32
5.4.1.3 Shut-off valves 32
5.4.1.4 Valves 32
5.4.1.5 Water flow protection device 32
5.4.2 Water pressure 33
5.4.2.1 Operating pressure 33
5.4.2.2 Boiler expansion vessel 33
5.4.2.3 System expansion vessel 33
5.4.2.4 Water pressure protection device 33
5.4.3 Water temperature 33
5.4.4 Water quality 33
6 Operating instructions 35
6.1 Operation 35
6.2 Controls 35
6.3 Boiler module KM628 35
6.4 Fault signals 37
6.5 Setting into operation 39
6.6 Switching-off the appliance 39
6.7 Warnings 39
7 Commissioning 40
7.1 General 40
7.2 Commissioning 40
7.3 Fuel Conversion NG-LPG LGP -NG 42
8 Maintenance 42
8.1 Safety 42
8.2 General 42
8.3 Procedure 43
8.4 Cleaning the burner and the heat exchanger 43
8.5 Cleaning the strainer of the gas combination block 43
8.6 Ionisation measurement 43
8.7 Service 43
9 Additional Information 44
9.0 Flue Terminal Positions 44
9.1 Wiring Diagrams 45
Notes 49

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WM Technical data
Type WM/45 WM/65 WM/85 WM/100 WM/120
Nominal heat output (80/600C) kW 5.6-39.2 8.3-59.2 15.6-77.8 17.6-88.2 21.9-109.8
Nominal heat output (40/300C) kW 6.3-43.0 9.2-65.0 17.0-85.0 19.2-96.3 24.0-120.0
Heat input, gcv (Hs) kW 6.4-44.4 9.5-67.4 17.7-88.8 19.9-99.9 25.0-124.8
Heat input, ncv (Hi) kW 5.8-40.0 8.6-60.7 16.0-80.0 18.0-90.0 22.5-112.4
Gas
consumption
Natural gas H
(10.9 kWh/m3) m3/h 0.5-3.7 0.8-5.6 1.5-7.3 1.7-8.3 2.1-10.3
Propane
(12.8 kWh/kg) kg/h 0.5-3.1 0.7-4.7 1.3-6.3 1.4-7.0 1.8-8.8
Gas inlet
pressure
Natural gas
(min./max.) mbar 17/20 17/20 17/20 17/20 17/20
Propane
(min./max.) mbar 30/50 30/50 30/50 30/50 30/50
Maximum water temperature of
central °C 90 90 90 90 90
heating system
Maximum operating pressure bar 6 6 6 6 6
Water content litre 5.1 6.6 8.4 10.3 12.0
Water resistance (∆T= 20°C) kPa 14 20 25 28 30
Excess head of the boiler pump
(∆T= 20°C) kPa 26 29 15 24 12
Connection for flue
outlet D mm 80 80 100 100 100
Connection for air
inlet D1 mm 80 80 100 100 100
Gas connection G R3⁄4" R3⁄4" R3⁄4" R3⁄4" R3⁄4"
Water connection W (int) Rp1" Rp1" Rp1" Rp1" Rp1"
W (ext) R11⁄4" R11⁄4" R11⁄4" R11⁄4" R11⁄4"
Condensate drain
(∅outer) mm 25 25 25 25 25
Electrical supply V 240 240 240 240 240
Frequency Hz 50 50 50 50 50
Fuse protection A 6 6 6 6 6
Maximum power
consumption
(excl.
pump) W 97 98 123 130 215
Maximum power
consumption
(incl.
pump) W 190 230 255 325 410
Insulation IPX4D IPX4D IPX4D IPX4D IPX4D
Boiler weight, empty,
± 5% kg 45 55 65 80 90
Table 1

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WM Dimensions
Type WM/45 WM/65 WM/85 WM/100 WM/120
B1 mm 120 120 140 140 140
D mm 80 80 100 100 100
D1 mm 80 80 100 100 100
G R 3⁄4" R 3⁄4" R 3⁄4" R 3⁄4" R 3⁄4"
L mm 340 405 510 560 670
L1 mm 74 90 90 90 90
W R 11⁄4"/Rp 1" R 11⁄4"/Rp 1" R 11⁄4"/Rp 1" R 11⁄4"/Rp 1" R 11⁄4"/Rp 1"
Table 2
(We reserve the right to make changes without prior notification)
The data may deviate slightly due to fabrication tolerances.
Conditions applicable to table 1:
- Gas consumption at: 1013 mbar, 15°C, dry.
- Gas category: 22H3P
- Category of appliance: B23, C13, C33, C43, C53, C63, C83
Service Clearances (Minimum)
Front Above Below Left-hand Side Right-hand Side
1000mm 400mm 250mm 100mm 100mm

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1 Introduction
1.1 General
Through their unique construction, the WM range of central heating units are renowned for their:
- High thermal output
- Environmental-friendliness (they meet the most stringent environmental conditions)
- Low weight and compact size
- Durability
- Low noise level
- Broad control range
- Can be supplied in a wide range of models
Through active and market oriented research, MHS Boilers Ltd is in a position to offer solutions
for the most challenging heating requirements.
1.2 The supplier
MHS Boilers Ltd are proud to supply and technically support the Ultramax WM Range of boilers
throughout the United Kingdom.
For advice or more information please contact your local sales representative or our head office via
01268 546700. or via our website www.mhsboilers.com
1.3 This document
The present documentation has been prepared with the following target groups in mind:
- The technical consultant
- The installer
- The maintenance technician
- The user
MHS Boilers Ltd has opted to make the technical documentation as comprehensive as possible in the
form of this book, in order to ensure that these target groups have all the information they need.
As the supplier we would be happy to help you in connection with any additional information that
you may require.
This document covers the following aspects relating to the boilers:
- General description
- Technical specifications
- Requirements for design and installation
- Maintenance instructions
The operating instructions for the user have been affixed to the appliance itself. You will also find them
in chapter six.

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1.4 Service
For commissioning and assistance in maintenance matters, please contact the Technical Services
Department via 01268 546700.
1.5 General restrictions
MHS Boilers Ltd products should always be used, installed and maintained in accordance with the
statutory requirements, specifications and standards applicable to these installations.
All the data, information and suggestions concerning its products provided by MHS Boilers Ltd are
based on careful study.
However, the use, installation and operation of the same are outside the control of MHS Boilers Ltd
and neither MHS Boilers Ltd nor any other organisations associated with it, accept any liability for the
same.
Changes may be incorporated without prior notice. MHS Boilers Ltd accepts no obligation to
adapt previously delivered products to incorporate such changes.
2 Description
2.1 General
All WM wall mounted boilers are environmentally friendly gas fired heating boilers with a modulation
range between approximately 20% and 100% of their maximum output.
The WM series consists of 5 models of boiler with an output range of 45 to 120 kW. The appliances
have low NOx and CO emission, which satisfy the most stringent environmental requirements.
The WM series has received CE Approval for all relevant European countries and has been registered
under the Product Identification Number 0063BO3192.
The boilers may be used on both open (category B23) as well as room sealed (category C13, C33,
C43, C53, C63 or C83) systems.
As standard, the boiler is delivered fully wired, fully assembled, and tested.
Working principle and design
Air is drawn in as required, via a speed controlled fan. The zero pressure controller of the gas valve
measures the under pressure in the venturi and modulates the gas in response to this pressure
from the fan. The gas/air is then thoroughly mixed in the correct ratio and passed directly into
the burner.
A temperature controller compares the actual water flow temperature to the desired water
temperature.
The controller interprets the load required and adjusts the fan speed. The fan sends a
speed feed-back signal, and the controller re-adjusts the speed as required.
The mixture of gas and air that is formed is then conveyed through the cylindrical stainless steel
burner for combustion.
The heat exchange takes place in a double heat exchanger block. The first heat exchanger is located
immediately next to the burner, while the second heat exchanger is connected downstream

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(condenser). Both heat exchangers consist of several smooth pipes in the form of a coil. The two
heat exchangers are connected to each other using water distribution manifolds. The water is
circulated by the boiler pump. This pump will be in the boiler for types 45, 65 and 85 and external for
the types 100 and 120 (supplied by the installer).
The WM boiler has a low water capacity. Due to this, rapid changes of the water temperature can
be achieved. It can be used without any return temperature protection. The installed pump provides
the water flow rate required. This pump has three-stage modulation (types 45, 65 and 85).
Application possibilities
The design of the WM boiler makes it suitable for use in heating systems with:
- constant flow temperature;
- weather dependent set point adjustment; Only in combination with an optional outside air sensor and
BM8 room unit.
- low temperature condensing system;
- external temperature control via building optimiser
(0 - 5 Vdc = -10°C + 90°C, below 1Vdc the boiler reverts back to the set temperature (P1), see
5.3.2 ‘connecting terminals’)

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2.2 Main components
1 Flue outlet connection 12 On/off switch
2 Air inlet connection 13 Condensate drain
3 Gas connection 14 Frame
4 Flow connection 15 Burner/ heat exchanger package
5 Automatic air vent 16 Water flow temperature sensor
6 Casing 17 Gas valve
7 Return connection 18 Venturi
8 Flue gas temperature sensor 19 Air intake silencer (types 45, 65 and 85)
9 Fan 20 Boiler pump (types 100 & 120 External)
10 Pressure Gauge 21 Control panel
11 Automatic boiler controller
2.2.1 Case Removal (Models produced post 01/01/07)
To remove the case panels use a flat bladed screwdriver to loosen the two brass screws located at the
base of the front sliding panel. With the screws hanging from the base of the front panel slide the front
panel up and disengage it from the unit.
The side panels are secured via toggle clips located on the top of the unit and location pins at the base.
The inner front panel is secured via an expansion toggle located at the top of the panel.

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2.2.2 Description of principal components
Fan [9]
The fan pulls in and compresses the combustion air, drawn from inside the casing of the boiler.
The fan is a DC current fan equipped with a speed feed-back signal. This speed feed-back signal
is transmitted back to the controller, which makes the necessary corrections.
Gas train
The main component of the gas train is the gas valve [17]. The gas quantity is controlled according
to the quantity of air. The air quantity varies with the speed of the fan. The gas train is equipped
with a test point through which the gas pipe can be vented or the gas inlet pressure can be measured.
Burner/heat exchanger package [15]
After the gas/air mixture has been correctly mixed, it flows into the burner via the inlet channel.
Due to the overpressure, the gas/air mixture is forced through the burner to the external surface
of the burner for combustion.
The heat exchanger is made of smooth stainless steel tubes in the form of coils. It essentially
consists of two parts; one part is located immediately next to the flame, where the major portion
of the heat transfer between the combustion gases and the water takes place. The other part
functions as a condenser for the flue gases, where the transfer of latent heat takes place.
Stainless steel water distribution manifolds ensure optimum water flow through the heat exchanger.
Water connections
These consist of a flow connection [4] and a return connection [7]. There is a water temperature
sensor [16] on the flow connection which, apart from controlling the burner load, also monitors
the water flow in the boiler. The latter is done in combination with the flue gas temperature sensor
[8].
Boiler pump [20]
The boiler pump of the types 45, 65 and 85 is located in the return connection of the boiler and
is electrically connected directly to the corresponding terminals in the control panel. The boiler
pump of the types 100 and 120 will be supplied by the installer and can be directly connected to the
return connection of the boiler. (Max 1 Amp) The capacity and the head of the pump is adequate to
overcome not only the boiler resistance but also some system resistance (see table 1). In the types 45
- 85, the pumps have three-stage modulation, depending on the load.
Condensate drain [13]
The boiler is equipped with a bottle trap. This bottle trap is located on the bottom side of the appliance
and should be easily filled with water prior to operation of the unit.
Frame [14]
The frame is the load bearing part of the boiler. All the components are installed on it.

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Casing [6]
The casing can be removed easily in 3 units. To do this, refer to the section 2.2.1.
Electrical equipment
This comprises of the control system and safety devices of the boiler. The connection terminals are
installed in a fully sealed enclosure behind the control panel [21]. This panel can be tilted through
90° after removing the control panel bolt. This provides access to all the electrical connections,
without the need to remove the casing. Slide the front case up to reveal the boiler control panel.
2.3 Boiler control
If heat is required, the boiler will start, if all necessary conditions have been fulfilled and no
safety devices have been triggered. This heat requirement will arise if:
- The flow temperature of the boiler is less than the required flow temperature
- The manual option has been selected using selector switch set to:
- The frost protection has been triggered independently of the operating conditions ( , , ,
The integrated temperature controller adjusts the heat input inside the boiler by changing the fan
speed so that the desired temperature is reached and kept at a constant level. Depending on the
quantity of air displaced by the fan, a specific quantity of gas will be added. As a result, the boiler
capacity can be modulated seamlessly and the heat requirement can be accurately monitored. If
the flow temperature rises above the desired level together with any hysteresis, the boiler will
switch off. The boiler will start again as soon as the flow temperature falls below the desired level.
2.4 Safety aspects
The following safety devices are installed on the boiler:
- Temperature monitoring system
- High limit temperature monitoring system (STW)
- Limit temperature monitoring system (STB) (both are adjustable)
- Frost protection system. Using an external sensor, if the external temperature falls below 0°C. Based
on the flow temperature, if this is below 5°C and/or the domestic hot water temperature is below 10°C
- Flame monitoring by means of ionisation measurement
- Fan speed monitoring
- Flue gas temperature monitoring
- Flow monitoring using a combination of flow water temperature and flue gas sensor readings
If one of these safety systems is activated, the boiler will go to an interlocking or lockout fault and
will be switched off. Lockout faults can only be reset by pressing the reset button, after rectifying
the fault.

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3 Safety
Installation specifications
Read the specifications before commencing with installation.
The equipment should be installed by a recognised installer in accordance with applicable national
and local standards and specifications.
The installation should only be used for heating systems with a maximum water temperature of
90°C.
It is expressly stated that these installation specifications should be regarded as a supplement to
the above mentioned standards and specifications, which shall take priority over the information
contained in this technical documentation.
Maintenance
Work on the electrical installation should only be carried out by a recognised installer in accordance
with the applicable electrical regulations.
Work on the gas equipment and hydraulic installation should only be done by personnel having
the required training, in accordance with the applicable safety rules and regulations for gas
installations.
Do not place any objects on the boiler. Keep a safe distance from the hot water connection and the
flue, due to the danger of burns.
Before starting with any maintenance and service work, shut off the electrical supply and close
the gas valve to isolate the gas supply.
Check the entire installation for leakages after completing maintenance and service work.
Casing parts may only be removed for maintenance and service purposes. After carrying out
maintenance and service work, replace all the panels.
Safety devices
The installation should never be switched on with the casing panels removed unless undertaking
repairs or preventative maintenance or the safety devices disabled.
Instructions and warning stickers
Instruction and warning stickers affixed on the appliance should never be removed or covered up,
and should be maintained in a legible condition throughout the life of the appliance. Immediately
replace damaged or illegible instruction and warning stickers.
Modification
The appliance may only be modified with the written permission of the manufacturer.
Danger of explosion
While doing work in the boiler room, follow the applicable rules and regulations entitled ‘Working
in Areas Subject to Danger of Explosion’.

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Installation
The appliance should be installed by a recognised installer in accordance with applicable national
and local standards and specifications.
Follow all the safety instructions precisely.
Operation
In case of a gas leakage: Prevent the boiler from operating and close the gas valve. Open doors and
windows
and notify the relevant authorities.
When the appliance is restarted, follow the user instructions.
Technical specifications
The specifications contained in this technical documentation should not be exceeded.
4 Delivery and transport
4.1 Delivery
The boiler is delivered fully assembled, tested, and packed.
Check the boiler for damage after receipt.
Check whether the items delivered are correct and in accordance with the items ordered.
4.2 Packaging
The boiler is delivered in suitable cardboard packaging.
The types 45, 65, 85 and 100 can be stacked two high. It’s not allowed to stack up the type 120.
4.3 Transport
Regarding transportation, refer to the technical data for dimensions and weights.
The packing should only be removed after transportation, or remove the panels before transportation.
This is in order to prevent the panels from getting damaged.
Moving
Each boiler is packed in its own carton which has hand holed at both sides for lifting purposes.
Access requirements
The dimensions of the boiler are such that all the boiler types can be transported through a door
opening of 60 cm.
Mounting
Install the WM using a spirit level on a sufficiently sturdy non-combustible wall using the suspension
bracket provided. A template has been provided in the packing box, on which the positions of the
fixing holes have been indicated.
Protection against frost
Boilers that are not used during the winter are in danger of freezing. Drain the system or add suitable
inhibitor.

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5 Installation
5.1 Regulations
The appliance should be installed by a recognised installer in accordance with the applicable
national and local standards rules and regulations.
The commissioning should preferably be done by the Technical Services Department of MHS Boilers
Ltd.
5.2 Installation area
5.2.1 General
- Thanks to the design of the boiler, radiation losses are negligible
- Due to the low noise level, there is no need for additional sound insulation of the room
- Due to its compact design, very little installation space is required
- The location options for the boiler are increased because it is supplied suitable for both open
and room sealed operation (see chapter 5.3.4).
5.2.2 Installation
The following guidelines should be followed in order to optimise the installation of the boilers
- The boiler should be installed in a frost free room due to the risk of freezing of the condensate drain.
The built-in protection system is activated when the temperature of the central heating water falls
below 5°C
- Pay attention to the location and temperature sensitivity of the boiler.
- Ensure that there is sufficient room around the boiler for maintenance and the replacement of
components if necessary.
The recommended minimum clearance is as follows:
- 1000 mm to the front (free space for movement);
- 400 mm above;
- 250 mm below;
- 100 mm Either side;
5.2.3 Ventilation (BS5440/BS6644/IGE-UP10/Clean Air Act)
The ventilation of the installation room should conform to the applicable national and local standards
and regulations. In connection with ventilation, keep in mind the following points:
a. Follow the applicable national and local standards and regulations concerning the dimensions
of the opening and the protection of the mechanical ventilation system if any
b. The air inlet openings could be in two walls facing each other
c. Use broad, low inlet grills
d. The ventilation outlet should be at high level as high as possible
e. In the case of insufficient air supply, it may be necessary to mechanically supply ventilation air.

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5.3 Connections
5.3.1 Gas connection
The gas connection should be installed by a recognised installer in accordance with applicable
national and local standards and specifications.
The gas connection is located on the bottom of the appliance.
The pressure on the inlet side of the appliance should be reduced to 20 mbar for natural gas and
up to 50 mbar for propane, using a gas governor.
The pressure loss in the supply pipe should be such that the pressure never falls below 18 mbar
for natural gas and 33 mbar for propane, when the appliance is at maximum load.
In order to guarantee that the gas valve works at all times, it is recommended that a gas filter is
installed in the gas pipeline. The gas filter can be ordered as an option to be supplied with the
boiler.
Install a gas isolating valve directly under the appliance.
5.3.2 Electrical connections
The electrical connections should be installed by a recognised installer in accordance with applicable
national and local standards and specifications.
The appliance is fully wired in accordance with the electrical diagrams delivered with the appliance.
All the electrical connections are located behind the control panel. The control panel can be easily
opened after removing the locking screw. The cables to be connected (supply, control) enter
through the bottom of the appliance via cable glands.
Fig. 4 Connections of the WM
The appliance is suitable for a 240 V 50Hz power supply with live/neutral/earth. Other connecting
arrangements are only permissible if an isolating transformer is used. The appliance is phase

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sensitive. The boiler can be switched on and off using the on/off switch on the control panel.
The installer should use a 2-pole main isolating switch with a contact opening of at least 3 mm in
the supply circuit to the boiler. With this, the entire boiler (including the boiler supply pump relay)
can be rendered volt free for maintenance work or in the case of failure.
In order to prevent faults due to electromagnetic fields, a screened cable should be used for
the bus connection and for all sensor and control signals between the boiler and all external
connection units. The screening should be connected on both sides according to the EMC
Directives.
Controls and options
The boilers are equipped with a modulating control system. The temperature can be controlled via
a 0-5 Vdc signal for example in response to external temperatures. If the voltage falls below 1 volt
the boiler reverts to the set point set on parameter P1. A hot water priority circuit also forms part
of the standard equipment, an additional sensor is required. Other options available on the boiler
can be supplied to extend this.
Ultramax WM Boiler Range
0-5 Control Signal Interpretation.
Constant Temperature zone = Controller P1 Temperature Set Point
The three following options are available:
BM8
A weather-dependent temperature controller with the following features:
- Programming of 3 heating periods with different room temperatures
- Adjustable night time boiler flow temperature reduction operation
- Choice between 2 weekly programmes
- Hot water priority circuit with 2 heat up periods
- Override for single hot water period during night time reduced flow temperature operation
- Optimum start time calculation
- Room temperature control with or without external temperature influence
- Option of internal (standard) or external room sensor (option)
- Adjustable response of the flow temperature to sensed room temperature

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- Calibration of the room sensor
- Delay to flow temperature compensation due to external temperature up to a maximum of
3 hours
- Holiday Programme
- Frost protection system based on external temperature or room temperature
- Remote activation via telephone if no external room sensor fitted (external relay required)
- Optimisation of compensation slope based on room temperature and external temperature
with optimum start time adjustment
- Hot water Anti-legionella bacteria function
- Option of switching off internal room sensor
- 2-wired communication (scom-bus)
- Display in 6 different languages
- External display of KM628 functions with display of status, operating hours, number of starts,
degree of modulation and temperatures.
BM8 Room Unit
Room Unit Mounting Plate Wiring Terminals
Terminal Designation
When connected to a Single Ultramax Boiler (2 Wire SCOM)
Terminal #s Voltage Screened Cable (Earthed
Screening) Description/Operation/Function
3 & 5
(Polarity Sensitive) <25V Yes SCOM Communication to boiler
(3 - & 5 +)
3 & 6
(Not Polarity Sensitive) <25V Yes Tamperproof RFB Remote
Sensor or Volt Free Enable
1 & 2 & 4 - - Not Used
When connected to a KKM8 or E8 Manager/Controller via a COCO2 (4 Wire CAN)
Terminal #s Voltage Screened Cable (Earthed
Screening) Description/Operation/Function
1 & 2 & 3 & 4
(Polarity Sensitive) <25V Yes CAN Communication to Controller
1 H, 2 L, 3 –, 4 +
3 & 6
(Not Polarity Sensitive) <25V Yes Tamperproof RFB Remote Sensor
or Volt Free Enable
5 - - Not Used

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E8.1121
This is a control system for the weather dependent control of two secondary heating circuits. In
addition, a hot water circuit can also be controlled at two different Set Points. All the settings can
be made separately for each secondary circuit. This E8 controller can be further extended with an
optimisation controller system for each secondary group (BM8). The weather dependent control of
the boiler is done indirectly by the E8.1121.
There are the following additional features to the BM8:
- The maximum flow temperature can be set for each heating circuit
- The compensation slope can be manipulated with a parallel displacement to the desired flow
temperature of the boiler
- Time controlled hot water Secondary pump
- Pump-exercise function
- DCF receiver for internal clock (optional receiver required)
- Communication over a CAN-bus
- Integrated relay and sensor test
- Can be used in stand-alone operation
Controller Wiring Terminals.(Rear of controller)(Housing available)

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Terminal Designation
Block Terminal #s Voltage Screened Cable
(Earthed Screening) Description/Operation/Function
II 1 230V - Permanent Neutral
2 & 3 230V - Permanent Live
4 230V - Heating Zone 1 Pump 230V Output (Max 1 Amp)
5 230V - Heating Zone 2 Pump 230V Output (Max 1 Amp)
6 230V - Do Not Use (Not Used With Ultramax Boilers)
7 230V - Heating Zone 2 Mixing Valve 230V ‘Open’ Output (Max 0.5 Amp)
8 230V - Heating Zone 2 Mixing Valve 230V ‘Close’ Output (Max 0.5 Amp)
9 & 10 230V - Do Not Use (Not Used With Ultramax Boilers)
VI 1 230V - Do Not Use (Multifunctional Relay 1 Output)
2 230V - Do Not Use (Not Used With Ultramax Boilers)
IV 1 230V - Heating Zone 1 Mixing Valve 230V ‘Open’ Output (Max 0.5 Amp)
2 230V - Heating Zone 1 Mixing Valve 230V ‘Close’ Output (Max 0.5 Amp)
3 & 4 & 5 230V - Do Not Use (Not Used With Ultramax Boilers)
IX 4 (Polarity
Sensitive) <25V Yes + Control Communication BM8 / E8 / COCO2* (*For Boiler Control.)
IX 3 (Polarity
Sensitive) <25V Yes - Control Communication BM8 / E8 / COCO2* (*For Boiler Control.)
IX 2 (Polarity
Sensitive) <25V Yes L Control Communication BM8 / E8 / COCO2* (*For Boiler Control.)
IX 1 (Polarity
Sensitive) <25V Yes H Control Communication BM8 / E8 / COCO2* (*For Boiler Control.)
III 3 & 2 <25V Yes Heating Zone 2 Volt Free Enable (3 + , 2 Ground).
1 <25V Yes Do Not Use (Not Used With Ultramax Boilers)
VIII 2 & 1 <25V Yes Do Not Use (Multifunctional Relay 1 Sensor Input)
V 2 & 1 <25V Yes Heating Zone 1 Flow Sensor (VFAS)
I 10 & 9 <25V Yes
Outside Air Sensor (AFS)
(Mounted on North Facing Wall)(BM8 Required to activate weather
compensation)
8 & 7 & 6 <25V Yes Do Not Use (Not Used With Ultramax Boilers)
5 & 4 <25V Yes Heating Zone 2 Flow Sensor (VFAS)
I 3 & 2 <25V Yes Heating Zone 1 Volt Free Enable (3 + , 2 Ground).
1 <25V Yes Do Not Use (Not Used With Ultramax Boilers)
VII 2 & 1 <25V Yes Do Not Use (Not Used With Ultramax Boilers)

MHS Boilers Ltd ©
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20
KKM8
This is a boiler cascade manager with which up to 8 boilers can be connected in cascade and an
extra on/off boiler can be operated. The KKM8 also has the same functional features as the E8.1121.
Controller Wiring Terminals.(Rear of controller)(Housing available)
Terminal Designation (230 Volt Terminals)
Block Terminal #s Voltage Screened Cable
(Earthed Screening) Description/Operation/Function
II 1 230V - Permanent Neutral
II 2 & 3 230V - Permanent Live
II 4 (A1) 230V - Heating Zone 1 Pump 230V Output (Max 1 Amp)
II 5 (A2) 230V - Heating Zone 2 Pump 230V Output (Max 1 Amp)
II 6 (A3) 230V - Hot water Charging Pump 230V Output (Max 1 Amp)
II 7 (A4) 230V - Heating Zone 2 Mixing Valve 230V ‘Open’ Output (Max 0.5
Amp)
II 8 (A5) 230V - Heating Zone 2 Mixing Valve 230V ‘Close’ Output (Max 0.5
Amp)
II 9 & 10 230V - Do Not Use (Volt Free Stage One Burner Enable)
VI 1 & 2 230V - Do Not Use (Volt Free Stage Two Burner Enable)
IV 1 (A8) 230V -
Heating Zone 1 Mixing Valve 230V ‘Open’ Output (Max 0.5
Amp)
(Multifunctional Relay 1 Output)
IV 2 (A9) 230V -
Heating Zone 1 Mixing Valve 230V ‘Close’ Output (Max 0.5
Amp)
(Multifunctional Relay 2 Output)