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SUNDIAL Y PLAN
Y PLAN
FEATURES
■
Independent control of
heating zone
■
Independent control of domestic
hot water temperature
■
Pump & boiler switched off when space
and hot water temperature requirements
are satisfied
■
Both systems can operate at
the same time
T6360
ROOM
THERMOSTAT
L641
CYLINDER
THERMOSTAT
T
SUNDIAL SYSTEMS
V4073
3 PORT
MID
POSITION
VALVE
IMER
OPTIONS
■
Programmable thermostat in
heating zone to provide
‘Best Practice’ system
■
Radiator thermostats may be fitted
to provide temperature control
in selected rooms/areas
■
CM Zone can provide wireless boiler
interlock for individual radiator control
APPLICATION
The Sundial Y Plan is designed to provide independent
temperature control of both heating and domestic hot water
circuits in fully pumped central heating installations.
Sundial Y Plan satisfies the minimum standard requirements
of the Building Regulations Part L1 when used in conjunction
with radiator thermostats and an automatic bypass valve.
For systems in dwellings with a floor area greater than 150m
Sundial S Plan Plus must be used (see 2.3).
2
,
© Honeywell Control Products and Systems, Issue 10
2.5
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SUNDIAL Y PLAN
■ Installation
Valve - Water flow must be into port
AB. Port A is the outlet connection to
the radiator circuit and port B to the
cylinder primary circuit.
Room Thermostat - The thermostat
must be located where not subject to
extraneous heat gains, direct sunlight
or draughts.
Cylinder Thermostat - For optimum
performance the thermostat should be
located between
cylinder from the floor.
1
/4and1/3up the
■ Time Control
Standard Practice
A 2 channel programmer to control the
HW and heating zones.
Best Practice
A time switch to control HW and a
programmable thermostat for the
heating zone.
Bypass Valve - An automatic bypass
valve should be fitted to the system to
stop wastage of energy and prevent
increased pressure within the circuit.
Even though there is always one valve
outlet open: the bypass will guard
against the possibility of the heating
circuit being isolated by radiator
thermostats or operation of manual
radiator valves.
■ Specification
Standard Sundial Y Plan comprises:
V4073A1039 : 22mm 3 port mid-position valve
L641A1039 : Strap-on cylinder thermostat
T6360B1028 : Room thermostat
ST9400C1000 : 7 day full programmer
or
ST9400A1002 : 1 day full programmer
Automatic Bypass Valve
DU144A1001 : 22mm straight auto bypass valve
DU145 –3/4B : 22mm angled auto bypass valve
Optional components
Y6630D1007 : Wireless analogue room thermostat
T6620B1008 : DT200 digital room thermostat
Best Practice
CMT901A1044 : 1 day programmable thermostat
CMT907A1041 : 7 day programmable thermostat
Frost protection
T4360A1009 : Frost Thermostat
L641B1004 : Low limit Pipe Thermostat
■ Typical Wiring
■ Operation
Hot Water Only Requirement - On a
demand for heat from the cylinder
thermostat, the valve remains open to
DHW only and the pump and boiler are
switched on.
Heating Only Requirement - On a
demand for heat from the room
thermostat, the valve motor is
energised so that the CH port only is
opened and the pump and boiler are
switched on.
HTG and HW Requirement - When both
thermostats demand heat, the valve
ball is positioned to allow both ports to
be open and the pump and boiler
switched on. When neither thermostat
is demanding heat, the pump and
boiler are off. The valve remains in the
last position of operation whilst the
mains is switched on.
Note: It is recommended that the 10 way Junction Box or Sundial Wiring Centre
should be used to ensure first time, fault free wiring.
© Honeywell Control Products and Systems, Issue 10, 2.5
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