Viessmann VITOCAL 250-A - Further Components of the Safety Concept

48
1
B
C
A
B
C
2
Fig. 16
!
Refrigerant-free heating water from condenser
?
Heating water containing refrigerant from con-
denser
Safety valve
A
Refrigerant
B
Float
C
Heating water
Discharge of refrigerant via the quick-action air
vent valve
The heat pump (indoor and outdoor unit) and heating
circuits are automatically vented using the quick-action
air vent valve that has been specially tested for refrig-
erant R290. Due to the arrangement of the quick-
action air vent valve at the top of the float air vent
valve, very small quantities of refrigerant can be
removed via this automatic venting process. As pro-
pane is heavier than air, the refrigerant escapes from
the outdoor unit via the condensate pan and evapo-
rates.
The quick-action air vent valve must always be open.
Note
A maximum of 38 l/h of air containing propane can
escape via the quick-action air vent valve. Mixing with
the ambient air in the interior of the outdoor unit does
not lead to the formation of an ignitable mixture. There
is no risk of sparking from the existing electrical com-
ponents.
Removal of refrigerant via the discharge pipe of
the safety valve
If large quantities of refrigerant flow into the float air
vent valve, the float is pushed all the way down and
seals off the heating flow completely. The refrigerant is
removed downwards from the outdoor unit via the
internal safety valve with discharge pipe and evapo-
rates.
Further components of the safety concept
Non-return valve
A non-return valve is installed in the heating water
return of the outdoor unit. This prevents any heating
water containing refrigerant from entering the heating
circuit directly from the condenser.
Function description
Float air vent valve (cont.)
6218234
Functions