1592021021 XC1008-1011-1015D GB A5 r.1.5A 12.10.2009 XC1008-1011-1015D 45/66
8. SCREW COMPRESSORS
Loads activation is managed by the neutral zone. They follows general rules of step compressors:
a. C1..C14 = screw1 or screw2 have to be present, following C2..C15 that are set as Stp, are linked
to C1..C14 = screw
The relay group is activated depending on the kind of screw compressors that has been selected on
the C16 parameter.
8.1 Regulation with screw compressors like Bitzer/ Hanbell/
Refcomp etc
Screw compressors like Bitzer use up to 4 valves for the power regulation.
The first valve is used during the starting phase for the C35 max time, after this time, the step 2 is
automatically activated.
Through the C36 parameter it is possible to decide if the step 1 can be subsequently used during
the standard thermoregulation.
8.1.1 Relay activation
ES. Compressor with 4 steps:
C1 = Scrw1; C2 = Stp; C3 = Stp; C4 = Stp; C16 = Btz
a. Activation with valves ON due to voltage presence (C17=cL).
C1 = Screw1 C2 = stp C3 = stp C4 = stp
Step 1 (25%)
ON ON OFF OFF
Step 2 (50%)
ON OFF ON OFF
Step 3 (75%)
ON OFF OFF ON
Step 4 (100%)
ON OFF OFF OFF
b. Activation with valves ON due to voltage absence (C17=oP).
C1 = Screw1 C2 = stp C3 = stp C4 = stp
Step 1 (25%)
ON OFF ON ON
Step 2 (50%)
ON ON OFF ON
Step 3 (75%)
ON ON ON OFF
Step 4 (100%)
ON ON ON ON
8.2 Regulation with screw compressors like Frascold
Screw compressors like Frascold use up to 3 valves for the power regulation.
The first valve is used during the starting phase for the C35 max time, after this time, the step 2 is
automatically activated.
Through the C36 parameter it is possible to decide if the step 1 can be subsequently used during
the standard thermoregulation.
8.2.1 Relay activation