7.4
Installation Diagram for OSO Unvented Twin Coil tank with HE26 Boiler
Room
thermostat
240 volt
switched
supply
Electrical connection; All
connections are 240 volt
therefore use 240 volt
switch live on boiler
terminals (1 is the switched
live input)
Gas
supply
Solar coil flow and return
connections
Pocket for
solar
sensor S2
Hot water out to taps
Terminal box
Solar cutout
stat &
Immersion
heater
Flow
Return
Thermostat for
boiler control.
Pocket for solar
sensor S3
(optional)
P&T valve
to tundish
and
discharge
Commissioning
valve and
Secondary hot
water return (if
required)
Two port
motorised
valves
Time-clock
programmer
Flow and return to radiators
Cold inlet with valve
assembly as supplied
with tank
Atmos
InterSystem HE26
condensing gas
boiler
Note
Tank is OSO unvented tank with internal
secondary expansion
Note: This is a diagrammatic illustration
only, and does not override manufacturer’s
instructions for boiler and unvented hot
water tank.
Solar circuit shown on page 9.
Twin Coil Sealed Solar System Ins Man
Page 14 of 15
