Pressure Relief Valve; Filling The System; Testing The Water System - Navien NCB-20LHWE Installation & Operation Manual

4.4 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
o 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.

4.5 Filling the system

Before lling the boiler pipes, pull up the air ue cap to allow the
pipes to ll properly. Press the cap back in when the pipes are
full.
Ensure that the ue cap is tted before testing or
Note
operating the system.
Refer to the following illustration for system ll.
Double
Check
Stop
Valve
Valve
Temporary
Loop
Cold mains Inlet
24 Installing the System Piping
Air Flue Cap
Stop
Valve
Space hating Return
The system must be lled with approved
Note
equipment and comply with all regulations for
system ll.
To perform an air purge after initially lling the
boiler pipes, the pump will run for 5 minutes and
20 seconds. The boiler will operate normally after
performing an air purge.

4.6 Testing the Water System

WARNING
Ensure that the boiler is full of water before ring the burner.
Operating the unit without lling it will damage the boiler.
Such damage is not covered by the warranty, and may result
in property damage or severe personal injury.
Perform a ll test after installing the boiler's water system to
make sure that the system has been installed properly. Follow
the instructions below to perform a ll test on the water system.
1. Close the manual air ues and the boiler drain valve.
2. Fill the boiler. The correct pressure will vary with each
application.
3. If the pressure is lower than the minimum pressure set (1 bar
by default), error code E02 will appear on the display.
4. Fill the boiler with more water until the error message
disappears.
5. At initial ll and during boiler start-up and testing, check
the system thoroughly for leaks. Repair any leaks before
proceeding further.
WARNING
Eliminate all system leaks. The continual introduction of fresh
makeup water will reduce boiler life. Minerals can build up in
the heat exchanger, reducing heat transfer, overheating the
heat exchanger and causing heat exchanger failure.
CAUTION
Before operating the boiler for the rst time, ensure that the
boiler system is lled with water. Purge the air inside the
system to avoid damage to the boiler.