Brochure

33AB218186428184en-US1501
GENERAL INFORMATIONPRODUCT INFORMATIONINTEGRATION INTO SYSTEMORDERING INFORMATION SYSTEM DESIGN
Manage superheat
Test, criteria and
solutions
Test N° Purpose Test condition Pass criteria Solutions
Liquid flood
back test
Steady-state
Liquid flood back testing must be
carried out under expansion valve
threshold operating conditions: a
high pressure ratio and minimum
evaporator load (A).
Suction superheat >5K(9°F)
1. Check expansion valve selection
and setting.
2. Add a suction accumulator*.
Transient
Tests must be carried out with most
unfavorable conditions :
• fan staging,
• compressor staging
• …
Refer to flood back chart criteria
1. Check expansion valve selection
and setting.
-For Thermostatic expansion valve
(TXV) check bulb position...
-For Electronic expansion valve (EXV)
check measurement chain and PID....
2. Add a suction accumulator*.
Defrost test
Check liquid
floodback
during defrost
cycle
Defrost test must be carried out in
the most unfavorable condition (at
32°F evaporating temperature).
Refer to flood back chart criteria
In reversible systems, the defrost
logic can be worked out to limit
liquid floodback effect. (for more
details see “Control Logic”).
A
*Suction accumulator offers protection by trapping the liquid refrigerant upstream from the compressor. The accumulator should be
sized at least 50 % of the total system charge. Suction accumulator dimensions can impact oil return (gas velocity, oil return hole size…),
therefore oil return has to be checked according to section “Manage oil in the circuit”.
0
3.6
7.2
10.8
14.4
18.0
21.6
25.2
28.8
32.4
-13 -4 5 14 23 32 41 50 59
Sump Superheat, °F
Floodback Requirement
Saturated Suction Temp. °F
Acceptable
Unacceptable