WarmFlow Solar SHP20, System Manual

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18
3.5.3 Connect back-up heat source
The controller is equipped with a 3-period, 24-hour programmer with temperature control to
control the back-up heat source, such as a boiler or immersion heater(s). The back-up heat
source is powered / controlled via the H1 outputs of the control unit.
Note: The maximum operating current on the H1 contacts is 5A. If immersion heaters are
used they MUST be powered via an external relay. Powering an immersion heater directly
will overload the control unit. Failure due to overloading is not covered by the guarantee.
If connecting to an unvented cylinder, the back-up heat source MUST be connected via an
external wiring centre and an energy cut-out devise MUST be installed in order to comply
with the Building Regulations. This MUST take the form of a 2-port motorised valve (not
supplied) wired through a manually-reset high limit thermostat (not supplied). If in doubt,
consult the cylinder manufacturer.
Only if connecting to an open-vented cylinder can the back-up heat source be connected
directly to the system controller without a motorised valve.
Figure 18 shows a typical single-heating-zone S-plan system with two 2-port motorised
valves. Additional heating zones can be added as required.
Figure 18: Wiring layout with external wiring centre
G
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y
O
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B
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SSC~ Control Unit
H1
Permanent
Mains Supply
(via fused spur)
Heating
Zone Valve
Diagram supplied for guidance only.
Detailed instructions on how to wire the high limit thermostat of the solar cylinder should be sought from the cylinder
manufacturer’s instructions, as differences may exist between products.
L N E
C
H
O
F
F
C
O
M
C
H
O
N
CH Programmer
L1 N L2
CH Room Stat
E
N
External Wiring Centre
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G
/Y
B
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B
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G
/Y
N N
B
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B
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G
/Y
N
N
Cylinder
Zone Valve
(on back-up coil)
Cylinder
High Limit
Thermostat
N
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Back-up Heat Source
(e.g. Boiler)
Back-up Circuit
Circulating Pump
(if applicable)
B
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G
/Y
N
B
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G
/Y
N
B
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n
B
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