INSTALLATION
6 720 803 800 (2012/11)
29
Fig. 53 Fitting the Programmer/Timer
4.7.2
NEW COMPLETE SYSTEM INSTALLATIONS
If a new complete heating system installation is in a new build property
or is a first time installation in an existing property, heating systems must
conform to current building regulations Part L1a.
All new heating systems in dwellings must have at least two heating
zones. Each of these zones will be controlled by a thermostat and zone
valve.
An alternative would be individual electronically controlled TRVs. Hot
water supplied from a storage system would require separate time and
temperature control.
If the dwelling is over 150m
2
, than a separate time and temperature
control for each zone is required.
All radiators must have TRVs fitted in all rooms except bathrooms and
rooms with room thermostats.
The exception to this are single storey, open plan dwellings where the
living area is more than 70% of the total useable floor area. Then this
type of dwelling can be controlled as one zone.
Figures 54 and 55 give some suggestions regarding zoning the system
for a small dwelling, less than 150m
2
, using either a third party
programmer or a Worcester programmer.
THIRD PARTY EXTERNAL TIMER AND TWO ZONES
Fig. 54 Two room thermostats, one external timer
INTEGRATED TIMER AND TWO ZONES
Fig. 55 Two room thermostats, one integrated timer
4.7.3
EXISTING INSTALLATIONS
For boiler replacements on an existing system, it is not necessary to zone
the upstairs and downstairs separately, compliance with the zone
requirements can be achieved by a single room thermostat or
programmable room thermostat.
While the system is drained down, TRVs must be fitted to all rooms
except the bathrooms and the room with the room thermostat.
The following figures show the options of room thermostat with
programmer, room thermostat only or programmable room thermostat.
Part number
Description
7 716 192 036 MT10 mechanical timer
7 716 192 037 MT10RF mechanical thermostat
7 716 192 038 DT20 twin channel digital timer
7 716 192 054 DT20RF digital RF thermostat with twin channel
programmer
7 716 192 052 DT10RF digistat
7 716 192 053 DT10RF optimiser
7 716 192 065 FR10 intelligent room thermostat
7 716 192 066 FR110 programmable room thermostat
7 716 192 067 FW100 weather compensation controller
Table 13 Controls accessories
6720646608-1
171W
o
5.
8.
7.
6.
3.
4.
230V
MAINS
SUPPLY
N
E
L
L
N
E
4
5
6
7
8
9
10
E
N
L
L
N
230V
IN
230V
OUT
FR FS LR LR
L
N
L
N
L
N
L
N
L
N
6720646608-36.1W
o
N
Zone 1
Room Thermostat
N
Zone 2
Room Thermostat
M
~
L
N
E
Zone 1
Zone Valve
M
~
L
N
E
Zone 2
Zone Valve
E
CH ON
PreHeat
Programmer
230V
MAINS
SUPPLY
Plug in
Worcester timer.
(see timer operating
instructions for
installation)
N
E
L
L
N
E
4
5
6
7
8
9
10
E
N
L
230V
IN
230V
OUT
FR FS LR LR
L
N
L
N
L
N
L
N
L
N
6720646608-37.1W
o
N
Zone 1
Room Thermostat
N
Zone 2
Room Thermostat
M
~
L
N
E
Zone 1
Zone Valve
M
~
L
N
E
Zone 2
Zone Valve
L
L
