4
Alpha CombiMax Secondary Circulation
3.1
PIPEWORK INSULATION
As hot water is circulated around the loop from the CombiMax cylinder it loses heat. To minimise heat loss it is essential that all
pipework within the circulation loop is adequately insulated. For this reason it is recommended that the secondary loop is in 15 mm
pipe, as larger diameter pipework would increase the heat loss.
3.2
ADDITIONAL EXPANSION VESSEL
The expansion vessel supplied with the CombiMax is sized to suit the CombiMax cylinder and a limited length of pipework only.
Depending on the length of pipework within the secondary loop an additional expansion vessel may be required. If there is insufficient
expansion vessel capacity the expansion relief valve fitted to the cylinder of the CombiMax will operate and discharge.
As a guideline, If the secondary loop is less than 25 metres of 15 mm diameter pipe, an additional expansion vessel should not
be required. If the loop is longer, it is recommended that an additional expansion vessel is fitted in the circuit, where it will be
accessible for inspection and servicing.
Note: The vessel must be acceptable for use on mains water and have a pre-charge of 2.5 bar. A suitable vessel is available
from Alpha Therm, Part No. 0001045.
3.3
DHW CLOCK
Sometimes it may be required to switch off 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 Fig. 4.
3.4
CLEARANCES REQUIRED
These are the same as stated in the installation and Servicing instructions supplied with the CombiMax.
3
INSTALLATION INFORMATION
4.1
UNPACKING
Before installation the CombiMax must be converted for secondary circulation. Carefully unpack the CombiMax box. Check that
you have all the components and place them safely to one side.
Check that the secondary circulation kit is the correct one, i.e. CombiMax 350, Part No. 1000461 or CombiMax 600, Part No.
1000466.
The kit supplied contains the following:-
a.
Secondary circulation return pipe, fitted with non-return valve and recirculation thermostat with cable. (Pipe 'A', in
schematic diagram on page 3).
b.
Recharge pipe. (Pipe 'B', in schematic diagram on page 3).
c.
Secondary circulation flow/boiler return pipe assembly, fitted with restrictor, flow regulator and housing. (Pipe 'C', in
schematic diagram on page 3).
d.
Literature, sealing washers and 'Converted to secondary circulation' label (fitted to the thermostat cable).
4
INSTALLATION
Fig. 2a - CombiMax 350
Fig. 2b - CombiMax 600
