18
Mexico Super RS 3/40 - 3/80 -
Installation
23 FROST PROTECTION
INSTALLATION
Diagram A
shows a double pole frost thermostat, which should suffice
for all systems which do not use the OFF terminals of the programmer.
Diagram B
shows a 'change-over' frost thermostat, which will cover
most systems which do use CH OFF. If, however, on such a system
the HW pipework is in an isolated part of the house, a second frost
thermostat may be used to protect it.
If in doubt, ask your installer for advice.
INST
ALLA
TION
24 FITTING THE CASING
7.
Insert the thermostat phial and phial retaining clip
into the thermostat pocket. Take care not to kink the
thermostat capillary as it is unwound and secure it
with the split pin as shown.
8.
Refit the grille assembly
Central heating systems fitted wholly inside the house
do not normally require frost protection as the house
acts as a 'storage heater' and can normally be left at
least 24 hrs. without frost damage. However, if parts of
the pipework run outside the house or if the boiler will 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 case
the programme selector switches are set to OFF and all
other controls MUST be left in the running position.
The frost 'stat should be sited in a cold place but where
it can sense heat from the system.
Wiring should be as shown, with minimal disturbance to
other wiring of the programmer.
Designation of the terminals will vary, but the programmer
and thermostat manufacturer's leaflets will give full
details.
1.
Offer up the RH side panel, locating it with the peg in the
baseplate, and push the panel back.
2.
Secure the panel to the baseplate and collector hood.
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 be neatly
secured with the cable straps provided and MUST NOT be
allowed to touch the burner front plate, or the cleanout cover and
the collector hood.
6.
Replace the control box cover and refit the control panel
using the screws previously removed.
25 COMMISSIONING AND TESTING
WARNING.
Whilst effecting the required gas soundness test and purging air from the gas installation,
open all windows and doors, extinguish naked lights and
DO NOT SMOKE.
A.
ELECTRICAL INSTALLATION
1.
Checks to ensure electrical safety should be carried
out by a competent person.
2.
ALWAYS carry out preliminary electrical system checks,
i.e. earth continuity, polarity, resistance to earth and
short circuit using a suitable test meter.
B.
GAS INSTALLATION
1.
The whole of the gas installation, including the meter, MUST
be inspected and tested for soundness, and purged in
accordance with the recommendations of BS. 6891.
2.
Purging air from the gas installation may be expedited by
loosening the union on the gas service cock on the boiler and
purging until gas is detected.
3.
Retighten the union and check for gas soundness.
