Nibe VEDEX 4000 - Buffer Tank System Configurations; Two-Tank System (Closed Expansion); Closed System Safety Considerations; Overheating Prevention (Closed System)

24 VEDEX 4000
Docking to two tanks with thermal charge control and closed expansion vessel
RC
AVT
LV
AV
AV AV
BV
SV4
CP2
SV1
SV2
T
T
T
VVB
ACCUACCU
ELK
AV
AVT AVT
AV
CP1
AV
SÄV
SÄV
EXP
A
V
SV3
TG
Closed expansion vessel and emergency
cooling presupposes there being sucient
cold water supply in event of, for example, a
power cut.
NOTE
In installations with closed expansion vessel a ther-
mal valve to prevent overheating must be connected
from the cold water to the boiler cooling coil, then to
a suitable drain.
Overow water from the safety valve is routed to a
drain so that hot water splashes cannot cause injury.
The entire length of the overow water pipe must be
inclined to prevent water pockets and must also be
frost proof.
When the boiler’s temperature exceeds the set
charge temperature (for example, 75°C) the charge
pump starts, which then transfers heat from the boiler
to the accumulator. The thermal charge control en-
sures that the water temperature to the bottom of the
boiler does not drop so much that there is a risk of
condensation.
The expansion vessel volume must be dimensioned
according to the applicable norms.