10
Installation and Servicing
Section 1 - General
1.11 BOILER CONTROLS
Install CH controls to ensure that the boiler has no demand
when there is no requirement from the system.
Heating systems with TRVs in individual rooms must include a
thermostat to control the temperature in rooms without TRVs.
At least 10% of the minimum boiler heat output should be
achieved using a room thermostat. A bypass circuit with an
automatic bypass valve must be fitted to systems with TRVs
or two-port valves on all the radiators to ensure water flow.
1.12 ELECTRICAL SUPPLY
Wiring external to the appliance MUST be in accordance with
the current I.E.E. (BS7671) Wiring Regulations and any local
regulations which apply.
The mains supply to the boiler and system wiring centre
shall be through one common fused double pole isolator and
for new heating systems, and where practical replacement
installations, the isolator shall be situated adjacent to the
appliance.
1.13 CONDENSATE DRAIN
The condensate drain provided must be connected to the
drainage point on site. All condensate drainage pipework and
fittings must be made of plastic
.
IMPORTANT:
The condensate drain pipework should
be installed in accordance with BS6798.
The drain outlet on the boiler is sized for standard 21.5 mm
overflow pipe. It is a universal fitting to allow use of different
brands of pipework.
Refer to Section
2.15
Whilst the principle of the 1:1 gas valve ensures the Logic
range is able to deliver it is full output at inlet pressures as low
as 14 mb, other gas appliances in the property may not be as
tolerant. When operating pressures are found to be below the
minimum meter outlet of 19 mb these should be checked to
ensure this is adequate for correct and safe operation.
Allowing for the acceptable pressure loss of 1mb across the
installation pipework, it can be assumed that a minimum
permitted operating pressure of 18mb will be delivered to the
inlet of the appliance.
(Reference BS6400-1 Clause 6.2 Pressure Absorption).
The external gas cock could further reduce the operating
pressure when measured at its test point. The pressure drop
is relative to the heat input to the boiler (kW), refer to graph on
P10.
IMPORTANT:
Ensure all gas valve connections are
gas tight with a gas soundness check up to the gas control
valve.
Installation pipes must be fitted in accordance with BS6891.
The complete installation MUST be tested for gas tightness
and purged as described, for the majority of installations the
appropriate standard is IGEM/UP/1B [23], but alternatively
IGEM/UP/1 [21] or IGEM/UP/1A [22], as appropriate, can be
utilized.
Gas Cock Pressure Drop
Heat Input to Boiler (kW)
Pressure Drop (mbar)
0 5 10 15 20 25 30 35 40
1.4
1.2
1
0.8
0.6
0.4
0.2
0
1.10 WATER CIRCULATION SYSTEM
IMPORTANT:
A minimum length of 1 metre of copper
pipe MUST be fitted to both flow and return connections from
the boiler before connection to any plastic piping.
The central heating system should be in accordance with
BS6798 and, in addition, for smallbore and microbore
systems, BS EN 12828:2012+A1:2014..
Water treatment is covered later in these instructions.
Refer to Section
1.17
WARNING:
This appliance must be earthed
