Operation Manual

10
 mount a heating system charge and discharge cock and a sludge cock at the lowest point of the system
in the very proximity of the electric boiler
 separate all electric boiler types on inlet and outlet by stop valves, too (see standards CSN 06 8030), not
to be forced to discharge the whole system in case of inspection or repair of the boiler or during filter
replacement
 remove control levers from stop valves and secure them against manipulation.
♦ Boiler connection to electric network
Wiring can be installed only by an authorized person in the sense of the Decree No. 50/1978 Coll. on
professional qualification in electrical engineering. Certification of the boiler installation and putting into
operation must be noted in a proper manner on the letter of guarantee. Any interference with internal boiler
wiring (with the exception of wiring specified in this Manual, e.g. the external regulator connection instead of
jumper wire) are inadmissible!
The boiler control box must be connected according to the relevant CSN standard by means of a
separately protected line which enables its disconnection and which is located in the very proximity of the
electric boiler!
Current protective switch must be used if the electric boiler is installed in a bathroom.
The power wiring is connected by a 5-conductor system to the U, V, W, N and PE terminals. In the case of a
4-conductor system the N and PE terminals shall be connected together and the power wiring matched with the
U, V, W and PE terminals.
If MRC is connected to the boiler control box, the MRC receiver outlet is matched with the terminal marked
HDO/N.
1
WARNING! When using the MRC receiver signal on the HDO/N terminal, it must be made sure that all
contactor coils of other appliances (e.g. of the boiler if it is connected to the common MRC signal) are
energized with the same phase!
When operation must be delivered also outside the so-called “low tariff”, the maximum boiler output
limit can be switched off in the service menu also without the MRC signal (P4.4)!
Recommended cable cross sections under the plaster:
Boiler output [kW] 8 15 23 30 38 45
Power take-off [A] 12 24 36 48 60 72
PVC insulated cable with copper
conductors 5 [sq.mm]
2,5 4 6 10 16 25
♦ Charging the heating system
For the duration of the heating system charging, the boiler must be unplugged from the electric network by
disconnecting it by the main circuit breaker. It is useful to maintain the level of filling pressure in a cold system
in the range between 1 and 1.5 bar. Filling must proceed slowly in order to let the air bubbles escape through
the respective valves. According to CSN 07 7401 the water used for the first filling as well as for refilling must
be clear, colourless, without any suspended substances, oil or chemically aggressive admixtures, with a
minimum carbonate hardness (max. 3.5 mval/l) and it cannot be acidic (pH cannot be below 7). Only approved
agents can be used for water hardness adjustments.
1
HDO is the Czech abbreviation for MRC: translator's note.