Data Sheet for Product

3/6
Smart Infrastructure Frost units QAF81... CA1N1284en
2021-08-31
Engineering notes
Withdrawable tray:
It is recommended that the frost unit QAF81... should be installed on a purpose-built
withdrawable tray directly downstream of the heating coil. The connecting cable must
be long enough to enable the tray to be inserted and removed without difficulty.
For heating coils with very large cross-sections, a number of frost units can be fitted
and connected in series. In this case, the setpoint must be set individually on each frost
unit.
Fitting notes
The ambient temperature affecting the frost unit housing (with the test loop) must be at
least 2 °C above the pre-selected setpoint. If this cannot be guaranteed (e.g. outdoors
or in exposed spaces), the housing and test loop must be installed inside the supply air
unit.
The capillary must be mounted on the downstream side of the heating coil (and on the
upstream side in the case of coiling coils). It should be looped diagonally across the
heat exchanger pipes at a distance of approximately 5 cm, and should cover the entire
area evenly. For test purposes, it is advisable to leave a loop of approximately 20 cm
directly beneath the housing outside the entry to the duct.
To prevent damage to the capillary it should be protected by grommets or similar where
it passes through metal walls.
To prevent damage to the capillary, a minimum bending radius of 20 mm must be
ensured.
Mounting is easier if the capillary tube clamps (FK-TZ1 or AQM63.3) are used.
Commissioning notes
After removal of the locking screw (under the housing cover) the setpoint can be
adjusted from above with a screwdriver.
To simulate frost conditions, the test loop can be immersed in a vessel of iced water.
To simulate frost with the frost unit QAF81.6M, push in the reset button (on the housing
base).
Frost thermostat
Capillary
Frost simulation