8
♦
Connecting the boiler to the hot-water system
The electric boiler shall be connected to the distribution system in such a way so as to avoid presence of air
in the system. As the boiler is a hot-water flow boiler fitted with its own pump, its connection the heating
system needs to be carried out based on a design following calculations of the hydraulic relations for the entire
system. To use the output to the maximum and to ensure proper operation and a long service life, it is necessary
to maintain a minimum overpressure of the heating system of 0.5 bar.
Before testing and commissioning, the heating system shall be flushed out thoroughly until it is completely
clean following a procedure indicated in CSN 06 0310. To prevent contamination of the boiler system, the inlet
of return water from the heating system into the boiler must be fitted with a suitable filter and sludge separator.
The heating system must be implemented in accordance with
CSN 06 0830
– Heating systems in buildings –
Security equipment and with
CSN 06 0310
– Heating systems in buildings – Design and assembly.
!!! We recommend:
charging the system with soft water according to CSN 07 7401;
separating the electric boiler (any type) on both the input and output with a shut-off valve (see CSN 06
8030) so that it is not necessary to discharge the entire system in case of an inspection or repair of the
electric boiler or cleaning of the filter.
♦
Connecting the boiler to the mains
Electrical wiring shall only be carried out by an authorized person within the meaning of Regulation no.
50/78 Coll., on electrical engineering qualifications. Certification of the boiler installation and commissioning
shall be appropriately recorded in the warranty card. No interventions with the internal wiring of the boiler
(unless otherwise mentioned in this manual - e.g. connection of an external regulator instead of the jumper, etc.)
shall be permissible!
The boiler control panel shall be connected according to CSN through wiring with independent
protection which can be switched off in the immediate vicinity of the electric boiler!
If the electric boiler is installed in a bathroom, a residual current device needs to be used.
Supply in a 5-wire system is connected to terminals L1, L2, L3, N, PE, while in a 4-wire system N and PE
terminals are interconnected and supply is connected to terminals L1, L2, L3, PE.
In case of HDO connection (demand site management) to the control cabinet of the electric boiler, the HDO
receiver input is connected to terminal HDO/N.
ATTENTION!
When a signal from the HDO receiver to terminal HDO/N is used, make sure that
all the
coils of other appliances´ contactors
(e.g. also of the boiler if it is connected to the common HDO signal)
are
powered by the same phase!
Recommended cable diameters under plaster:
♦
Connecting the electric boiler to a single phase
In some cases, the THERM ELN 8 electric boiler can be connected to a single phase system only. For such
cases, a jumper is included which interconnects all the three terminals L1, L2 and L3. The supply cable with a
max. diameter of 6 mm
2
can then be connected to any of the three terminals L1, L2 or L3. We recommend
protection with a single-phase circuit breaker according to the table! The jumper and the screws are included in
the delivery. Before the connection, the plastic partitions separating the terminals of the individual phases need
to be removed.
Boiler output (kW)
8
15
Current consumption [A]
12
24
CYKY 5 [mm
2
]
2.5
4
