Showers; Expansion Vessel (Ch Only); Safety Pressure Relief Valve - Baxi 224 Combi 2 Installation And Service Manual

5 Before installation
Fig.10 Discharge pipe
1
A
24 Combi 2
Important
Failure to flush and add inhibitor to the system will invalidate the
appliance warranty.
It is important to check the inhibitor concentration after installation, system
modification and at every service in accordance with the inhibitor manufac­
turer. (Test kits are available from inhibitor stockists.)
For information or advice regarding any of the above contact Baxi Custom­
er Support 0344 871 1545.
5.2.7

Showers

If a shower control is supplied from the appliance it should be of the ther­
mostatic or pressure balanced type. Thermostatic type shower valves pro­
vide the best comfort and guard against water at too high a temperature.
Existing controls may not be suitable - refer to the shower valve manufac­
turer.
5.2.8

Expansion vessel (CH only)

The appliance expansion vessel is pre-charged to 1.0 bar. Therefore, the
minimum cold fill pressure is 1.0 bar. The vessel is suitable for correct op­
eration for system capacities up to 100 litres. For greater system capaci­
ties an additional expansion vessel must be fitted.
For GB refer to BS 7074 Pt 1. For IE, the current edition of IS 813 Domes­
tic Gas Installations.
Checking the charge pressure of the vessel - to check the charge accu­
rately ensure the system is cold. It is also necessary to relieve the pres­
sure by draining the boiler. Using a suitable gauge check the pressure at
the valve on the underside of the vessel. Adjust the pressure as required
and repressurise the system.
5.2.9

Safety pressure relief valve

1 Discharge pipe
2 Pressure relief valve
A The end of the pipe should terminate facing down and towards the
wall
See
BS 6798 for full details.
The pressure relief valve is set at 3 bar, therefore all pipework, fittings, etc.
should be suitable for pressures in excess of 3 bar and temperature in ex­
cess of 100°C.
The pressure relief discharge pipe should be not less than 15mm diame­
ter, run continuously downward, and discharge outside the building, pref­
erably over a drain. It should be routed in such a manner that no hazard
occurs to occupants or causes damage to wiring or electrical components.
If it is anticipated that any part of the pipe may be subject to freezing it
should be suitably insulated. The end of the pipe should terminate facing
down and towards the wall.
The discharge must not be above a window, entrance or other public ac­
cess. Consideration must be given to the possibility that boiling water/
steam could discharge from the pipe.
Important
The relief valve must never be used to drain the system.
A remote relief valve kit is available to enable the boiler to be installed in
cellars or similar locations below outside ground level.
A boiler discharge pump is available which will dispose of both condensate
& high temperature water from the relief valve. It has a maximum head of
5 metres.