Navien NCB300-28K, Руководство по установке и эксплуатации

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Installing the System Piping 29
4.6 Filling the System
Before filling the boiler pipes, unscrew the air vent cap(
❶
) to
allow the pipes to fill properly. Screw up the cap when the pipes
are full.
❶
Air Vent Cap
Note
●
Ensure that the air vent cap is fitted before testing
or operating the system.
●
To perform an air purge after initially filling the
boiler pipes, the pump will run for 5 minutes and
20 seconds. The boiler will operate normally after
performing an air purge.
4.4 Pipe Dimensions and Water Pressure
The requirements recommended for the pipe dimensions and
water pressure are as follows:
●
The connection diameter for the domestic cold water inlet
must be at least Ø15 mm.
●
If a shut-off valve is fitted at the domestic cold water inlet, it
must have a safety valve incorporated, calibrated to 9 bar.
●
For DHW production installation, the inlet pressure must be
over 0.5 bar.
●
For hot water supply to the second floor of a building, the
minimum pressure required is 1.0 bar.
●
The pipe diameter is not determined by the boiler connection
but must be calculated in accordance with its length and
consequent pressure drop.
4.5 Pressure Relief Valve
The requirements recommended for the pressure relief valve are
as follows:
●
The pressure relief valve is calibrated to be activated at a
maximum pressure of 3 bar, and all the pipes and connections
must therefore be able to withstand pressures of up to 3 bar.
●
Connect the pressure relief valve drain to a tube with a
diameter of at least Ø15 mm. It must tilt in a downstream
direction throughout its entire length, and the water must run
off to a suitable drain. It must be positioned so as not to cause
damage to cabling, electrical equipment or persons.
●
The drain must not be located above a window, entry door or
any other public access point. Bear in mind that boiling water
or steam could come out when draining.