7
Alpha CombiMax Secondary Circulation
6
OPERATION
When a secondary circulation loop is fitted, the CombiMax will still operate as described in section 6 of the instructions supplied
with the CombiMax, except that the DHW pump will not be switched off until both the store thermostat and recirculation
thermostat are satisfied. The recirculation thermostat senses the temperature of the water returning to the store from the
secondary circulation loop and will only switch the pump off when the water in the loop has reached the set temperature of
approximately 56°C.
Domestic hot water always takes priority over central heating. If a demand for hot water is required during a central heating
period, the boiler will automatically switch to the hot water mode until the demand is satisfied, i.e. storage water and circulation
loop have reached the set temperature. This interruption in the central heating is only when the demand for hot water is
present, or when recharging of the circulation loop and store is required.
It is the law that any service work must be carried out by a competent person.
Warning: Before replacing any boiler or CombiMax 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 and CombiMax for full details on replacement of all other components.
7.1
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.
7.2
DRAINING THE COMBIMAX - See CombiMax Schematic illustration
Isolate the electricity supply.
Remove the front casing as described in section 7.1. Close the mains water inlet valve. Open any hot tap below the level of the store
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, open the drain tap at the bottom of the store.
Note: Some water will remain in the components and care must be taken when removing them.
7.3
RECIRCULATION THERMOSTAT - See CombiMax Schematic illustration
1.
Gain access as described in section 7.1. 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.
7.4
NON RETURN VALVE - See CombiMax Schematic illustration
1.
Drain the CombiMax as described in section 7.2.
2.
Undo the unions of the pipe containing the non return valve.
3.
Remove the non return valve
4.
Re-assemble in reverse order with a new valve and seals.
5.
Refill the store as described in section 7.6.
7.5
BOILER FLOW CONTROL REGULATOR - See Fig. 3
1.
Drain the CombiMax as described in section 7.2.
2.
Refer to Fig. 3 and disconnect the pipework containing the regulator.
3.
Remove the regulator from its housing.
4.
Re-assemble in reverse order with a new regulator.
5.
Refill the store as described in section 7.6.
7.6
REFILL 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 on page 3) 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.
7
COMPONENT REPLACEMENT
