27Mexico Super 100 FF & 125 FF - Installation50 FROST PROTECTIONINSTALLATIONuse the OFF terminals of the programmer.Diagram B shows a 'change-over' frost thermostat, which will covermost systems which do use CH OFF. If, however, on such a systemthe HW pipework is in an isolated part of the house, a second frostthermostat may be used to protect it.If in doubt, ask your installer for advice.51 FITTING THE CASING7. Insert the thermostat phial and phialretaining clip into the thermostat pocket.Take care not to kink the thermostatcapillary as it is unwound and secure itwith the split pin as shown.8. Refit the in-line electrical connectorbetween the control box and the PCBbox.9. Refit the grille assembly.Central heating systems fitted wholly inside the housedo not normally require frost protection as the houseacts as a 'storage heater' and can normally be left atleast 24 hrs. without frost damage. However, if partsof the pipework run outside the house or if the boilerwill be left off for more than a day or so then a frost'stat should be wired into the system.This is usually done at the programmer, in which casethe programme selector switches are set to OFF andall other controls MUST be left in the running position.The frost 'stat should be sited in a cold place but whereit can sense heat from the system.Wiring should be as shown, with minimal disturbanceto other wiring of the programmer.Designation of the terminals will vary, but theprogrammer and thermostat manufacturer's leafletswill give full details.Diagram A shows a double pole frost thermostat,which should suffice for all systems which do not1. Offer up the RH side panel, locating it with the pegin the baseplate, and push the panel back engagingit into the collector hood tab.2. Secure the panel to the baseplate and turret frontpanel.3. Repeat steps 1 and 2 to refit the LH side panel.4. Place the top panel and push back.5. Secure the top panel to the side panels.IMPORTANT. Wiring within the boiler casing must beneatly secured with the cable straps provided andMUST NOT be allowed to touch the fan coolingimpellor, the burner front plate, or the cleanout coverand the collector hood.6. Replace the control box cover and refit the controlpanel using the screws previously removed.INSTALLATION