4.2 Start-up
Start-up, Indirect heating
Filling:
1: First fill
When carrying out first fill, the heat exchanger must be slowly filled
with water until it reaches working pressure.
2: Pressure gauge
The HE pressure gauge indicates the pressure of the HE system. This
instruction must be followed strictly, to avoid dangerous situations.
3: Supply hose
A ball valve with plug is installed in the HE return line. To fill the
system, the ball valve must first be closed, the plug removed and
a supply hose connected. On re-opening the ball valve, system
fill can commence.
4: Pre-pressure
When filling the system with water, the pressure gauge should be
observed closely. The expansion vessel is supplied pre-pressurised
to 0.5 bar. The pre-pressure required at each substation will
depend on system head (the distance between the lowest and
highest point in the system), for example:
5: Filling stop
Filling must stop when the pressure gauge shows a pressure
approximately 1-2 bar higher than the pre-pressure setting. The
ball valve is then closed, the hose removed and the plug put back
in.
Start-up:
1: Pump speed
Set the pump to highest speed before start-up.
2: Start pump
Start the pump and heat through the system.
3: Open shut-off valves
The shut-off valves should then be opened and the unit observed
as it enters service. Visual checking should confirm temperatures,
pressures, acceptable thermal expansion and absence of leakage.
If the heat exchanger operates in accordance with design, it can be
put to regular use.
4: Vent system
Switch off the pump and vent the installation after the radiators
have been warmed up.
5: Adjust pump speed
Set the pump to the lowest speed consistent with comfort and
electricity consumption.
Normally the change-over switch is set in the mid position (default).
However for systems with under floor heating or single pipe loop
systems, it may be necessary to turn the change-over switch
upwards.
Higher pump speeds are only used if the heating requirement
increases.
Re-tighten connections
After water has been added to the system and the system has been
put into operation, re-tighten
ALL
ALL
ALL
connections.
Pump
The pump must be switched off during system fill.
Height (m)
Pressure (bar)
0 – 5
0,5
5 – 10
1,0
10 – 15
1,5
15 – 20
2,0
AQ082486478026en-010501/ LUK4044301
© Danfoss | 2023.10 | 7
Operating Guide Termix VVX-I with complete insulation
