Alpha Alpha CombiMax 350 User guide

Installation and Servicing
Instructions
Leave these instructions with the User
Alpha CombiMax 350 and 600
Unvented Hot Water Store
for use with the
Alpha 240/280 Range of Gas Fired Combination Boilers
Building Regulations
Certificate No. ETC 03198
These instructions must be used in conjunction with the Installation instructions provided
with the selected combination boiler.
Nepicar House, London Road,
Wrotham Heath, Sevenoaks,
Kent TN15 7RS
For Technical help or for Service call ...
ALPHA HELPLINE
Tel: [phone]

2Alpha CombiMax 350 and 600
CONTENTS
1 Introduction ....................................... 2
2 Technical data................................... 3
3 Installationinformation ....................... 5
4 Installation......................................... 7
5 Commissioning ................................. 11
6 Operation .......................................... 13
7 Routine servicing............................... 13
8 Componentreplacement ................... 14
9 Wiringdiagrams ................................ 16
10 Short parts list ................................... 17
11 Faultfinding ...................................... 17
12 Appendix 1 (remote location) ............. 18
The CombiMax is a wall mounted unvented secondary hot water storage cylinder for use with the Alpha 240/280 range of gas
fired combination boilers.
Two models are available - the CombiMax 350 with a 35 litre capacity and the CombiMax 600 with a 60 litre capacity.
The store is supplied with a pump, thermostats, pressure reducing valve, check valve, expansion vessel, expansion relief
valve, temperature/pressure relief valve and tundish. It is also supplied with all the required fittings and pipework to enable
connection to the selected Alpha combination boiler.
The CombiMax provides hot water at temperatures of up to 56°C at flow rates of up to 18 l/min (4 gal/min).
Note: To enable this flow rate to be achieved:-
1.The cold water mains supply must be able to deliver 22 l/min to the appliance.
2.Pipework to the hot water outlets should be as short as is practical and have minimal pressure loss.
The CombiMax can be converted to enable a secondary circulation loop to be connected to it, thus supplying domestic hot
water immediately a hot water tap is opened. The CombiMax pump is used to circulate the hot water within the loop. For full
details contact Alpha Therm Ltd.
The CombiMax storage cylinder has the facility for fitting an electric immersion heater (which must be obtained from Alpha
Therm Ltd.) and an external clock for timing the domestic hot water operation.
IMPORTANT
This appliance has been approved to the Building Regulations for unvented hot water storage systems and the Local Authority
must be notified of the intention to install. Therefore the installation must be carried out by a person competent to install
unvented hot water systems in accordance with the following recommendations:-
All relevant Building Regulations issued by the Department of the Environment
Building Standards (Scotland) (Consolidation) Regulations issued by the Scottish Development Department
Local Water Bye Laws
Health & Safety Document No. 635 (The Electricity At Work Regulations 1989)
The installation should also be in accordance with the following British Standard Codes of Practice:-
BS 5546:1990 Installation of hot water supplies for domestic purposes
BS 6700:1987 Design, installation, testing and maintenance of services supplying water
BS 7671:1992 Requirements for electrical installations, IEE Wiring Regulations
Failure to install this appliance correctly could lead to prosecution. It is in your own interest and that of safety to ensure that the
law is complied with.
Manufacturer's instructions must NOT be taken in anyway as over-riding statutory obligations.
NOTE: Failure to use an Alpha boiler with the CombiMax will invalidate its approval, warranty and may be unsafe.
1 INTRODUCTION

3
Alpha CombiMax 350 and 600
2 TECHNICAL DATA
8 bar
0.1 bar
15 mm
15 mm
35 L
60 L
4 L at 2.5 bar
5 L at 2.5 bar
2.5 bar
90°C/7 bar
4 bar
18.0
4.0
56
133
7.25 mins
12 mins
4.0 mins
7 mins
Domestic Hot Water
Max. Mains Inlet Pressure (inlet of pressure reducing valve)
Min. Mains Water Pressure
Mains Inlet Connection
DHW Outlet Connection
DHW Storage (350 model)
(600 model)
Expansion Vessel Size (pre-charge press.)
(350 model)
(600 model)
Pressure Reducing Valve Setting
Temperature and Pressure Relief Valve
Expansion Relief Valve Setting
Flow Rate L/min
G.P.M.
Outlet Water Temp. (Approx.) °C
°F
Time to raise water storage 50°C(350 model)
(600 model)
Reheat time for 70% of storage (350 model)
(600 model)
Min. Clearances required for Servicing
Top
Bottom
Sides
Front
Dimensions CombiMax Height
(350 model) Width
(600 model) Width
Depth
Overall width when fitted with boiler
(350 model)
(600 model)
Lift Weight of Store (350 model)
(600 model)
Weight Full and Operational (350 model)
(CombiMax and Boiler) (600 model)
2.2 INSTALLATION
Supply
External Fuse
Power Consumption
230/240 V ~ 50 Hz
3 A
90 W
2.3 ELECTRICAL
2.1 DOMESTIC HOT WATER
2.4 ELECTRICAL CONNECTIONS
Note: This Appliance Must Be Earthed
Boiler terminal block CombiMax terminal block
220 mm
250 mm
5 mm
450 mm
950 mm
270 mm
365 mm
360 mm
720 mm
815 mm
12 kg
25 kg
92 kg
130 kg
Supply
External Fuse
Power Consumption
230/240 V ~ 50 Hz
10 A
2 kW
Alpha Immersion Heater (optional)

4Alpha CombiMax 350 and 600
2.5 COMBIMAX SCHEMATIC
1. Gas service cock
2. On/Off valve and filter
3. On/Off valve
4. On/Off valve and filter
5. DHW pump
6. Pressure reducing valve with filter and check valve
7. Drain point
8. DHW expansion relief valve
9. Store thermostat
10. DHW expansion vessel
11. Manual air vent
12. DHW temperature/pressure relief valve
13. DHW outlet thermostat
14. Storage cylinder
15 Boiler flow control regulator
16 Non return valve
17 Immersion heater boss

5
Alpha CombiMax 350 and 600
3.1 ELECTRICAL SUPPLY
The CombiMax requires a 230/240 V ~ 50 Hz electrical mains supply.
This appliance must be earthed.
The mains supply to the CombiMax and boiler must be directly connected to the CombiMax terminal block, i.e. not the boiler. A
supply cable from the CombiMax terminal block has been provided for connection to the boiler terminal block.
Notes: 1. If an external control is to be fitted, it must be suitable for 240 V and it must be connected to the boiler terminal block.
2. If an external DHW clock is to be fitted, it must be suitable for 240 V and it must be connected to the CombiMax
terminal block.
Theremustonlybeonecommonisolator,providingcompleteelectricalisolation,fortheCombiMax,boilerandanyexternalcontrols.
However,ifan immersion heateristo be fitted,anindependant electrical supplymustbe provided.Refertothe instructionssupplied
with the Alpha immersion heater kit.
Theapplianceshouldbeconnectedtoafusedthreepinplugandunswitchedshutteredsocketoutlet(bothcomplyingwithBS1363),
or a fused double pole switch with a contact separation of at least 3 mm in both poles using heat resisting cable (i.e. 85°C) not less
than 0.75 mm² (24 x 0.2 mm) to BS 6500 Table 9.
Wiring external to the boiler must be in accordance with the current IEE Wiring Regulations (BS 7671).
Note:Ifanimmersionheateristobefitted,thismustbesuppliedbyAlphaThermLtd.andbeinstalledaspertheinstructionssupplied
with the kit. A standard 3 kW immersion heater must not be fitted.
DHW CLOCK - Sometimes it may be required to switch off the CombiMax and, if fitted, the secondary circulation overnight to
avoid unnecessary heat loss and operation of the appliance. This can be achieved by connecting an external clock to the 'Ext
Prog' terminals on the CombiMax terminal block, as shown in section 2.4.
Note: When the clock is in an OFF position the CombiMax will not operate, i.e. hot water will only be supplied from the water
left within the storage cyliner. Therefore the OFF periods should be set at times when hot water will not be required.
If a secondary circulation kit is to be fitted, refer to the instructions supplied with the kit.
3.2 LOCATION
The appliance is not suitable for external installation.
The CombiMax and boiler must be installed on a flat vertical wall which is capable of supporting a weight of approximately 92 kg
(350 model) or 130 kg (600 model)..
TheCombiMaxmay be installedinany roomorinternalspace, althoughparticularattention is drawntothe requirements ofthecurrent IEE
WiringRegulations,andinScotland,theelectricalprovisionsoftheBuildingRegulationsapplicableinScotland,withrespecttotheinstallation
in a room or internal space containing a bath or shower. Where it is installed in a room containing a bath or shower, it must not be possible
for a person using the bath or shower to touch any electrical switch or boiler control utilising mains electricity.
The appliance may be installed in a cupboard or compartment, provided it is correctly designed for that purpose and that the
requirements of BS 6798 are complied with.
The appliance does not require any air vents for cooling in the room in which it is installed or when installed in a cupboard or
compartment.
If required, the CombiMax (produced after February 1999, i.e. from serial No. A906) may be located remotely (up to 1 metre)
from the boiler. Refer to Appendix 1, starting on page 18.
3.3 DOMESTIC HOT WATER SYSTEM
To ensure a hot water flow rate of 18 l/min the mains water supply must be capable of delivering 22 l/min to the appliance at 2 bar.
The incoming mains water pressure is regulated to 2.5 bar within the Combimax by a pressure reducing valve. However, all taps
and mixing valves used with the hot water system must be suitable for operating at a pressure of up to 8 bar.
To ensure economic use, the pipe runs between the appliance and taps should be in 15 mm copper pipe and be as short as
possible. Where possible the pipework should be insulated to reduce heat loss.
Showers - A shower may be used with the CombiMax if required.
If a loose or flexible head type shower is used it may require the fitting of a double check valve, to comply with Water Bye Law 17.
Bidets - No anti-syphonage arrangements are necessary, provided the outlets are shrouded and it is not possible to attach a temporary
hand held spray. A supply of direct mains fed hot and cold water is permitted provided the appliance is of the over-rim flushing type.
Before the mains water supply pipe is connected, it should be thoroughly flushed out to avoid the danger of dirt or foreign
matter entering the CombiMax or boiler and the filter incorporated within the pressure reducing valve cleaned.
The stored water temperature is approximately 56°C. In hard water areas this should avoid possible scale build-up. However, if
descaling is necessary contact Alpha Therm Ltd. for guidance.
3 INSTALLATION INFORMATION

6Alpha CombiMax 350 and 600
3.4 UNVENTED HOT WATER STORAGE SYSTEM
The installation is subject to Building Regulations approval and the Local Authority must be notified of the intent to install.
The CombiMax store is supplied with the components required for an unvented hot water system, i.e. temperature/pressure and
expansionreliefvalves,expansionvessel,checkvalveandtundish.Allthesecomponentsarefactoryfitted,exceptfortheexpansion
vessel,whichistobeconnectedtothetopofthestoragecylinderafterinstallation,andthetundishwhichmustbeinstalledasfollows:-
Discharge pipe - The discharge pipes from both the temperature/pressure and expansion relief valves have been joined together
within the appliance. The combined discharge pipe from the appliance must be routed to the tundish supplied in 15 mm pipe.
Tundish - The tundish must be positioned within 500 mm of the appliance, so that it is visible to the User and away from electrical
devices. The minimum size of the discharge pipe downstream of the tundish is given in the following table.
Fig. 1a
300 mm
minimum
Tundish
500 mm max.
fromappliance
Metal discharge pipe (D2) from
tundishwithcontinuousfall
Metal discharge pipe (D1)
from relief valves to tundish
Temperature/pressure
relief valve
300 mm
minimum
100 mm max.
70 mm min.
Gulley if
available
Pipe close to wall to
allow water to fan out
safely
Groundlevel
D2
D1
LOW LEVEL TERMINATION
Resistance created
by each elbow
or bend
0.8 m
1.0 m
1.4 m
Maximum resistance allowed,
expressed as a length of straight
pipe (i.e. no elbows or bends)
up to 9 m
up to 18 m
up to 27 m
Minimum size of discharge
pipe 'D2' from tundish
22 mm
28 mm
35 mm
Minimum size of discharge
pipe 'D1' to tundish
15 mm
Valve
outlet size
G½
Sizing of copper discharge pipe 'D2' - refer also to Figs. 1a and 1b
The discharge pipework from the tundish:-
a. Shall fall continuously through its length.
b. Shall be of a heat resistant material, e.g. metal.
c. Shall not be fitted with any valves or taps.
d. Shall discharge to a safe visible position, e.g. onto the surface of an external wall or into a gulley.
e. Shall have a minimum of 300 mm straight pipework directly from the tundish.
Note: Where children may play or otherwise come into contact with discharges, a wire cage or similar guard must be
positioned to prevent contact whilst maintaining visibility.
Refer to Figs. 1a and 1b for suggested methods of terminating the discharge pipe safely.
Where a single pipe serves a number of discharges, such as in blocks of flats, the number served should be limited to not more
than 6 systems so that any installation can be traced reasonably easily. The single common discharge pipe should be at least
one pipe size larger than the largest individual discharge pipe to be connected.
If the system is installed where discharges from safety devices may not be apparent, i.e. in dwellings occupied by blind, infirm or disabled
people, consideration should be given to the installation of an electronically operated device to warn when discharge takes place.

7
Alpha CombiMax 350 and 600
4.1 UNPACKING
The boiler must be installed before the CombiMax store, so therefore carefully unpack the CombiMax box, check and safely
place all the components to one side until installation.
Note: To avoid damage, do not lift the store via the valves and pipework.
1. The CombiMax is supplied in one box containing the following:-
a. Assembled CombiMax store complete with its casing support brackets, controls and wiring centre.
b. Wall mounting frame.
c. Expansion vessel (4 litre with 350 model and 5 litre with 600 model) with a pre-charge of 2.5 bar and flexible hose.
d. Boiler connecting pipes, together with screws, wall plugs and washers.
e. Literature pack and DHW control knob label.
f. Boiler conversion kit with restrictor, spanner and boiler converted label.
2. Unpack the boiler as per the Installation instructions supplied with the boiler.
4.2 CLEARANCES REQUIRED - Fig. 2
4 INSTALLATION
Fig. 2
At high level, discharge onto a roof is acceptable providing the roof is capable of
withstanding high temperatures and there is a distance of 3 m from any plastic
guttering systems that would collect such discharge.
Note: The discharge will consist of scalding water and steam. Asphalt, roofing felt
and non-metallic rainwater goods may be damaged by such discharges.
HIGH LEVEL TERMINATION
Tundish
D1
D2
300 mm
minimum
D1
D2
300 mm
minimum
Tundish
Type 'A' air gap
End of pipe to be
clearlyvisible
Fig. 1b
TERMINATION INTO A HOPPER

8Alpha CombiMax 350 and 600
4.3 CONVERT THE BOILER FOR FITTING THE COMBIMAX - Figs. 3, 4, 5 and 6
The boiler may be converted before or after mounting it onto the
wall as described below.
When mounting the boiler onto the wall follow the installation
instructions supplied with the boiler.
Note: Do not connect the pipework, electrical mains supply or
fit the flue until the CombiMax has been fitted.
1. Lower the front cover and loosen the two fixing screws
securing the control panel as shown in Fig. 3.
2. Remove the left hand side panel of the boiler by removing
the top and two bottom screws as shown in Fig. 3.
Fig. 4
4. Modify the differential pressure sensor (see Figs. 5
and 6) as follows:-
a. Unscrew fitting 'A' and discard the components A,
B and C as shown in Fig. 5.
Fig. 5 - Differential pressure sensor BEFORE modification
b. Screw fitting 'D' (supplied in the conversion kit) into
the sensor body as shown in Fig. 6.
Fig. 6 - Differential pressure sensor AFTER modification
5. Re-assemble the differential pressure sensor into the boiler in reverse order.
Note: After converting the boiler, fit the label supplied in the conversion kit to the inside of the hinged cover so that it can be
seen when the cover is lowered.
Restrictor
Filter
Differential
pressure sensor
CBA
D
Fig. 3
3. Remove the differential pressure sensor from the boiler using
the spanner provided as follows:-
Disconnect the two flow sensing pipes from the right hand
manifold, then unscrew and remove the end fitting containing
the filter/restrictor as shown in Fig. 4.

9
Alpha CombiMax 350 and 600
4.4 FIT THE COMBIMAX - Figs. 7 and 8
1. Locate the wall mounting frame over the top left hand panel of the combination boiler to ensure correct alignment.
2. Drill five wall fixing holes (8 mm dia.) through the mounting frame (as shown in Fig. 7) and secure with the screws and
plugs provided.
3. Hang the storage cylinder on the mounting frame, ensuring the top and bottom brackets on the store locate on the supports
on the frame (see Fig. 7). Pass the plastic security strap around the cylinder and secure in position (see Figs. 7 and 8).
4. Connect the flexible hose to the expansion vessel and locate it in the space above the boiler to the rear, with the connection
to the left as shown in Fig. 8. Connect the expansion vessel hose to the connection on the top left hand side of the store.
CombiMax 600 only - Secure the vessel to the right side rear of the boiler frame with the two screws provided.
5. Fit the side support bracket to the boiler in place of the boiler left hand side panel, securing at both top and bottom as
shown in Fig. 8 (remove the front screw from the top of the room sealed chamber to secure the top of the bracket).
6. Fit the top support bracket (with two clips) to the top of the side support bracket and fit the bottom support bracket (with
four clips) to the bottom of the side support using the screws provided.
7. Fit the left hand side panel, removed from the boiler, to the CombiMax by hooking the top of the panel over the brown trim
of the mounting frame and securing it at the bottom rear of the panel. Secure the panel to the top and bottom support
brackets using the screws provided.
Fig. 7 Fig. 8
4.5 FIT THE FLUE
Install the flue in accordance with the Installation instructions supplied with the boiler or flue.
4.6 CONNECT THE PIPEWORK - Fig. 9
1. Thoroughly flush out all the water pipework.
Note: Ensure that all the plastic caps are removed from the boiler connections.
2. Secure all the valves/fittings between the CombiMax and boiler as shown in Fig. 9. Use the washers supplied and ensure
the necessary fittings face the rear wall. Fit the union bends to the valves.
Notes: a. If soldering to the boiler union bends, ensure the bends are not connected to the valves, otherwise the internal
seals may be damaged.
b. Ensure the 22 mm isolating valve with the filter is fitted to the heating return connection as shown in Fig. 9.
c. Fit the pressure relief valve connection before the isolating valves.
3. Connect the system pipework to the boiler.
Note: Do not forget that the heating system pressure relief valve discharge pipe must be routed clear of the boiler to a
drain in such a manner that it may be seen, but cannot cause injury to persons or property.
4. Connect the discharge pipework from the temperature/pressure relief and expansion relief valves to the tundish supplied.
Note: This pipework must be installed as recommended in Unvented Hot Water Storage System, section 3.4.

10 Alpha CombiMax 350 and 600
4.7 CONNECT THE MAINS SUPPLY - Figs. 9, 10 and 11
1. Remove the screws securing the CombiMax terminal block cover. Pass the electrical mains supply cable through the
cable clamp on the boiler and route the cable to the CombiMax terminal block as shown in Fig. 10. Connect the cable as
follows:- Brown to L, Blue to N and Green/Yellow to . Ensure correct polarity and that the cable is secured using the
clamping bush supplied.
Note: Ensure that the length of the earth wire is such that if the supply cable is pulled out of its clamp the live and neutral
wires become taut before the earth wire.
IfanexternalDHW clockistobe fittedtotheCombiMax terminal block,removethelink betweenterminalsLand S/L,seesection2.4.
Connect the clock cable to the 'Ext Prog' terminals N, L and S/L ensuring the cable is secured using the clamping bush supplied.
If a secondary circulation kit and/or an Alpha immersion heater is fitted, refer to the instructions supplied with the kit.
When all connections have been made to the CombiMax terminal block, replace the terminal block cover.
2. Remove the screw securing the terminal block cover from the back of the boiler control box as shown in Fig. 11. Route the
cable provided from the CombiMax terminal block to the boiler (see Figs. 9 and 10) and connect to the boiler terminal
block via the grommet as shown in Fig. 11. Refer to section 2.4 for connection details.
The boiler main terminal block can be removed by pulling it off the pins to give easy access to the terminals.
Do not switch on the electrical supply at this stage.
3. If an external control, i.e. room thermostat or external clock is to be fitted, remove the link between terminals 1 and 2 on
the boiler terminal block. Pass the cable through the cable clamp, through the grommet (cut as necessary) and connect it
to terminals 1 and 2, see section 2.4.
4. Replace the boiler terminal block, ensuring it is located correctly on the plastic pins and replace the cover.
5. Ensurethatthereissufficientfreecabletoallowthecontrolpaneltoberaisedandloweredthentightenthecableclampscrews.
6. Leave the control panel open until commissioning procedures have been completed.
7. Carry out electrical system checks - Short circuit, Polarity, Earth continuity and Resistance to earth with a suitable multimeter.
Note: Disconnect the filling loop after filling
the central heating system.
A- Heating flow (22 mm)
B- Hot water outlet (15 mm)
C- Gas inlet (22 mm)
D- Cold water mains inlet (15 mm)
E- Heating return (22 mm)
F- Heating pressure relief valve (15 mm)
G- Temperature/pressure expansion relief
discharge pipe
H- Drain point for DHW storage
Note: Both Heating return and Cold water
mains inlet valves contain serviceable filters.
Fig. 9a - CombiMax 350
Fig. 9b - CombiMax 600

11
Alpha CombiMax 350 and 600
Fig. 10 Fig. 11
Remove link to connect
external control
Fuse
T2A
Terminal block
cover
Cable
clamps
From CombiMax
The boiler must be commissioned as described in the Installation instructions supplied with the boiler.
5.1 FILL THE DOMESTIC HOT WATER SYSTEM
Open the mains water inlet valve and allow the CombiMax store and boiler to fill. When filled, open the manual air vent on the
top of the store (refer to schematic diagram in section 2.5) until all the air has been vented. Turn on all the hot water taps and
allow water to flow until no air is present. Turn off the taps. Cover all electrical components beneath the CombiMax pump and
then release the pump bleed screw until all the air has been vented. Retighten the screw.
5.2 BOILER CONTROLS - Fig. 12a, 12b or 12c
The domestic hot water thermostat must always be set to the maximum setting. A label has been supplied which must be
positioned over the domestic hot water thermostat knob.
5 COMMISSIONING
Clock
(if fitted)
System
Pressure
Gauge
Central
Heating
Thermostat
Domestic
Hot Water
Thermostat
()set at maximum
Selector
Switch
Gas
Control
Indicator
Neons
Pilot and Burner
Viewing Window
0
THERMOSTAT
0
THERMOSTAT
0
SELECTOR GAS
OFF
bar
04
3
2
1
Alpha 240P and Alpha 280P
Fig. 12a

12 Alpha CombiMax 350 and 600
Fig. 12b
5.3 INITIAL LIGHTING
When the selector switch is set to (DHW and CH) the boiler will not operate in the central heating mode until the
CombiMax store has reached a temperature of approximately 56°C. This will take between seven to twelve minutes from cold.
Depending on whether it is a CombiMax 350 or 600.
5.4 CHECK THE BURNER PRESSURES
Hot water mode
The burner will stay at maximum output for approximately three minutes and then the burner pressure will decrease slowly to its
minimum, until the hot water store reaches a temperature of approximately 56°C.
Check the burner pressure and that the burner goes out when the store is satisfied.
Central heating mode
The boiler will not operate in the central heating mode until the CombiMax store is satisfied.
Clock
(if fitted)
System
Pressure
Gauge
Central
Heating
Thermostat
Domestic
Hot Water
Thermostat
()set at maximum
Selector
Switch
Burner
Viewing Window
0
THERMOSTAT
0
THERMOSTAT
0
SELECTOR
bar
04
3
2
1
Indicator
Neons
Red
Reset
Button
White
Reset
Button
RESET
RESET
Alpha 240E and Alpha 280E
Fig. 12c
Alpha 240X

13
Alpha CombiMax 350 and 600
Refer to the instructions supplied with the boiler for full details of the operation of the boiler.
The CombiMax will supply hot water provided the selector switch on the boiler is set to either or .
Note: The clock (if fitted) only controls the operating times of the central heating, not domestic hot water - DHW is available
continuously, unless an external DHW clock has been fitted to the CombiMax.
Domestic hot water supply always takes priority over central heating. If a demand for hot water is required during a central heating period,
theboilerwill automaticallyswitchto thehotwater mode untilthe demand issatisfied,i.e. storagewateris totherequired temperature.This
interruption in the central heating is only when the demand for hot water is present and should not be noticed by the User.
When there is a demand for hot water (by opening a hot tap or temperature of the stored hot water is below the thermostat
setting) the store pump starts and circulates mains water through the boiler operating the boiler DHW flow switch. The burner
lights and the mains water is heated by the DHW heat exchanger. When the water in the store reaches a temperature of
approximately 56°C the store thermostat switches the store pump off.
When a hot tap is opened, hot water is supplied from both the store and boiler. When the temperature within the store falls
below the outlet thermostat setting, the hot water flow from the store is stopped and hot water is supplied (at a reduced rate)
from the boiler only.
5.5 FINAL COMMISSIONING
Thoroughly flush out the water pipework and water in the CombiMax store. Clean the filters within the pressure reducing valve
and the mains water inlet valve.
5.6 FINAL ASSEMBLY
After completing the assembly of the boiler, place the CombiMax front casing in position and secure it at the bottom with two
screws.
Note: Ensure the label has been fitted over the domestic hot water thermostat knob, and that it is set at maximum.
5.7 USER INFORMATION
The User must be advised (and demonstrated if necessary) of the following important points regarding the CombiMax:-
1. Explain the operation of the CombiMax.
2. The domestic hot water thermostat control knob on the boiler must be set and left at maximum.
3. If an immersion heater has been fitted, it must only be switched on if the boiler/CombiMax is not working.
4. Show the User the position of the pressure relief valve discharge pipes and tundish for the heating and DHW systems.
5. Hand the User's instructions to the User.
6. Leave these Installation and Servicing instructions with the User for use on future calls.
6 OPERATION
Note: It is the law that any service work must be carried out by a competent person.
The boiler must be serviced as described in the instructions supplied with the boiler, taking note of the following instructions
regarding the servicing of the CombiMax.
Warning: Before servicing the CombiMax or boiler ensure the electrical and gas supplies have been isolated.
Gain access: Remove the bottom two screws securing the CombiMax front casing and lift the casing up slightly and remove.
1. Inspect and clean, if required, the filter and cartridge in the pressure reducing valve and cartridge in the expansion relief
valve fitted to the store.
2. Check the charge in the domestic hot water expansion vessel and re-pressurise if necessary.
Check the charge only when the pressure in the mains supply is zero.
7 ROUTINE SERVICING

14 Alpha CombiMax 350 and 600
It is the law that any service work must be carried out by a competent person.
Warning: Before replacing any boiler components, isolate the electrical supply and close the boiler gas service cock.
After replacement of any components, check the operation of the CombiMax. Ensure that all the controls are returned to their
original settings.
Refer to the instructions supplied with the boiler for full details on replacement of the boiler components.
8.1 ACCESS
1. To gain access to the CombiMax, remove the bottom two screws securing the CombiMax front casing and lift the casing
up slightly and remove.
2. To gain access to the boiler, refer to the instructions supplied with the boiler.
8.2 DRAINING THE COMBIMAX - See CombiMax Schematic illustration
Isolate the electricity supply.
Removethefront casing asdescribedin section 8.1.Closethe mains waterinletvalve. Openanyhottap belowthelevelof thestore
and open the manual air vent on top of the store. Allow as much water to drain from the store as possible. To drain the remaining
water from the store, remove the drain plug at the bottom of the store.
Note: Some water will remain in the components and care must be taken when removing them.
8.3 DHW PUMP - See CombiMax Schematic illustration
1. Drain the CombiMax as described in section 8.2.
2. Disconnect the pump unions and withdraw the pump. Remove the wiring cover and disconnect the wiring.
3. Connect the wiring to the new pump as follows:-
Brown to L, Blue to N and Green/Yellow to
4. Ensure the pump is set to maximum (III) and re-assemble in reverse order, using new sealing washers.
5. Refill the store (refer to Commissioning, section 5.1).
8.4 DHW OUTLET THERMOSTAT - See CombiMax Schematic illustration
1. Gain access as described in section 8.1. Ensure the electricity supply is isolated.
2. Close the mains water inlet valve and open any hot tap below the level of the store.
3. Unscrew the thermostat retaining cap and withdraw the wax cartridge and spring (it may be necessary to release the
cartridge with the aid of a screwdriver).
4. Fit the new thermostat and re-assemble in reverse order.
5. Refill the store (refer to Commissioning, section 5.1).
8.5 STORE THERMOSTAT - See CombiMax Schematic illustration
1. Gain access as described in section 8.1. Ensure the electricity supply is isolated.
2. Cut and remove the plastic cable tie around the plug and disconnect the plug from the thermostat.
3. Remove the two fixing screws and remove the thermostat from the mains water inlet pipe.
4. Fit the new thermostat and re-assemble in reverse order, fitting a new cable tie around the plug and pipework.
8.6 NON RETURN VALVE - See CombiMax Schematic illustration
1. Drain the CombiMax as described in section 8.2.
2. Undo the unions of the pipe containing the non return valve between the store and boiler.
3. Remove the non return valve
4. Re-assemble in reverse order with a new valve and seals.
5. Refill the store (refer to Commissioning, section 5.1).
8.7 DHW TEMPERATURE/PRESSURE RELIEF VALVE - See CombiMax Schematic illustration
1. Partially drain the hot water circuit as described in section 8.2, so that the water in the store is below the relief valve
connection.
2. Remove the outlet thermostat as described in section 8.4.
3. Disconnect the valve pipework unions and remove the valve from the store.
4. Re-assemble in reverse order with a new valve.
5. Refill the store (refer to Commissioning, section 5.1).
8 COMPONENT REPLACEMENT

15
Alpha CombiMax 350 and 600
8.8 DHW EXPANSION VESSEL - See Fig. 8
Note: If a top rear flue has been fitted to the boiler, it may be necessary to loosen the flue connections to the boiler so as to
raise the height of the flue by approximately 10 mm to allow removal of the expansion vessel.
1. Close the mains water inlet valve and ensure that all hot water taps are closed. Release the pressure from the hot water
circuit by opening and closing a hot tap which is lower than the store.
2. Disconnect the expansion vessel union and for the CombiMax 600 remove the two screws securing the vessel to the right
side rear frame of the boiler.
3. Remove the expansion vessel.
4. Re-assemble in reverse order with a new vessel. Refill and pressurise the hot water circuit by opening the mains water
inlet valve.
8.9 DHW EXPANSION RELIEF VALVE - See CombiMax Schematic illustration
1. Drain the CombiMax as described in section 8.2.
2. Disconnect the valve pipework unions and remove the valve.
3. Re-assemble in reverse order with a new valve.
4. Refill the store (refer to Commissioning, section 5.1).
8.10 PRESSURE REDUCING VALVE FILTER/CARTRIDGE - See CombiMax Schematic illustration
1. Close the mains water inlet valve and ensure that all hot water taps are closed. Release the pressure from the hot water
circuit by opening and closing a hot tap which is lower than the store.
2. Unscrew the cartridge from the valve body.
3. Clean or replace the filter/cartridge and re-assemble in reverse order.
4 Refill and pressurise the hot water circuit by opening the mains water inlet valve.
8.11 PRESSURE REDUCING VALVE/CHECK VALVE - See CombiMax Schematic illustration
1. Drain the CombiMax as described in section 8.2.
2. Disconnect the unions of the pipe between the water mains inlet valve and pressure reducing valve, and remove the pipe
from the manifold plate.
3. Remove the pressure reducing valve/check valve.
4. Re-assemble in reverse order with a new valve.
5. Refill the store (refer to Commissioning, section 5.1).
8.12 BOILER FLOW CONTROL REGULATOR - See Fig. 9
1. Drain the CombiMax as described in section 8.2.
2. Refer to Fig. 9 and disconnect the pipework containing the regulator.
3. Remove the regulator.
4. Re-assemble in reverse order with a new regulator.
5. Refill the store (refer to Commissioning, section 5.1).
8.13 DHW STORAGE CYLINDER - See CombiMax Schematic illustration
1. Drain the CombiMax as described in section 8.2.
2. Disconnect the DHW expansion vessel connection to the cylinder.
3. Remove the DHW outlet thermostat as described in section 8.4.
4. Remove the DHW temperature/pressure relief valve as described in section 8.6.
5. Remove the DHW expansion relief valve as described in section 8.8.
6. Remove the DHW pump as described in section 8.3.
7. Remove the pressure reducing valve as described in section 8.10.
8. Remove the store thermostat as described in section 8.5.
9. Disconnect all the pipework from the cylinder.
10. Cut and release the plastic security strap and lift the cylinder upwards to disengage it from the mounting frame. Pull the
cylinder forward and remove it.
11. Re-assemble in reverse order with a new cylinder, using new seals and new plastic security strap supplied.
12. Refill the store (refer to Commissioning, section 5.1).

16 Alpha CombiMax 350 and 600
9 WIRING DIAGRAMS
9.1 COMBIMAX ILLUSTRATED WIRING DIAGRAM
9.2 COMBIMAX FUNCTIONAL FLOW WIRING DIAGRAM

17
Alpha CombiMax 350 and 600
10 SHORT PARTS LIST
Refer to section 2.5
Item 5
Item 6
Item 8
Item 9
Item 10
Item 10
Item 12
Item 13
Item 14
Item 14
Item 15
Item 16
-
Description
DHW pump - Grundfos UPS 15/60X18B
Pressure reducing valve - 2.5 bar
DHW expansion relief valve - 4 bar
Store thermostat - TOD
DHW expansion vessel - 4 litre
DHW expansion vessel - 5 litre
Temperature/pressure relief valve - 90°C/7 bar
DHW outlet thermostat - wax element
Storage cylinder - 35 litre
Storage cylinder - 60 litre
Boiler flow control regulator
Non return valve
Tundish
Qty.
1
1
1
1
1
1
1
1
1
1
1
1
1
Alpha Part No.
0001047
0001041
0001042
0001049
0001045
0001098
0001043
0001039
0001077
0001107
0001059
0001048
0001044
Model
Both
Both
Both
Both
350
600
Both
Both
350
600
Both
Both
Both
11 FAULT FINDING

18 Alpha CombiMax 350 and 600
12 APPENDIX 1
The Alpha CombiMax has been designed to fit onto the left hand side of an
Alpha 240/280 boiler. However, it is now possible (using a CombiMax 350 or
600 produced after February 1999, i.e. from Serial No. A906) to install it up
to a distance of 1 metre from the boiler in the positions shown in Fig. 13.
The pipework between the boiler and CombiMax must be kept as short as
possible and be no more than 1 metres in length, with the number of bends
kept to a minimum.
Notes: 1. A CombiMax produced before February 1999, i.e. before Serial
No. A906 must not be fitted remote from the boiler.
2. A CombiMax fitted remote has no casing.
Fig. 13
Possible locations
for the CombiMax in
relation to the boiler.
Fig. 14
12.2 COMBIMAX SCHEMATIC - remote location from boiler
1. Gas service cock
2. On/Off valve and filter
3. On/Off valve
4. On/Off valve and filter
5. DHW pump
6. Pressure reducing valve with filter and check valve
7. Drain point
8. DHW expansion relief valve
9. Store thermostat
10. DHW expansion vessel
11. Manual air vent
12. DHW temperature/pressure relief valve
13. DHW outlet thermostat
14. Storage cylinder
15. Boiler flow control regulator
16. Non return valve
17. Immersion heater boss
12.1 INTRODUCTION

19
Alpha CombiMax 350 and 600
Fig. 15
12.3 INSTALLATION
If the CombiMax is to be fitted in a remote location from the boiler, it should be installed as described in section 4, together with
the following important points:-
12.4 MINIMUM CLEARANCES REQUIRED
12.5 WALL MOUNTING
The wall mounting frame and security strap supplied, are to be used to secure the CombiMax storage cylinder to the wall.
12.6 CASING
The casing components supplied with the CombiMax cannot be used when it is fitted in a remote location from the boiler.
12.7 DHW EXPANSION VESSEL
Fit the expansion vessel near the top of the storage cylinder using the flexible hose supplied. See Fig. 15.

Manual compiled and designed by Publications 2000, Tel [phone]
Part No. 0001056/4
These instructions have been carefully prepared but we reserve the right to
alter the specification at any time in the interest of product improvement.
© Alpha Therm Limited 1999.
11/99/D112
Fig. 16
12.8 FILLING LOOP
With the CombiMax in a remote location from the boiler, the filling loop facility supplied with the boiler cannot be used as
designed. The filling loop should be discarded and its connections on the cold mains inlet valve (CombiMax) and heating return
valve (boiler) sealed, using ½" BSP threaded caps (not applicable to Alpha 240X). See Fig. 16.
12.9 CONNECTING PIPEWORK
The boiler and CombiMax must be connected together as shown in Fig. 16, using 15 mm pipework. The pipework supplied with
the CombiMax can be utilised to provide the connections at the boiler and CombiMax.
12.10 ELECTRICAL SUPPLY
Connect the electrical supply cable directly to the CombiMax terminal block as described in section 4.7, ensuring the cable is
secured with the clamping bush supplied.
The cable supplied fitted for connection to the boiler will be too short and therefore must be removed from the CombiMax terminal
block terminals 1, 2 and . A longer length cable to the same specification stated in section 3.1 must then be used to connect the
electrical supply to the boiler terminal block from the CombiMax.
Note: Connect this electrical supply to the boiler as described in the boiler instructions.
Alpha Therm Limited.
Nepicar House, London Road, Wrotham Heath
Sevenoaks, Kent TN15 7RS
email: [e-mail]
website: www.alpha-innovation.co.uk