Sporlan SHGBE-8 Discharge Bypass Valve without MKC-1 Coil, 1-1/8 Inch, ODF, 0 - 100 psi, Pilot Operated
DISCHARGE BYPASS VALVES The selection of a Sporlan
Discharge Bypass Valve involves five basic items:
1. Refrigerant - valve capacities vary considerably for
different refrigerants.
2. Minimum allowable evaporating temperature at the
reduced load condition - depending on the system,
this value must be set to prevent coil icing and/or
compressor short cycling. For example, this may be
32°F - 34°F for a water chiller; 26°F - 28°F for a normal
air conditioning system; and, the freezing temperature
of the specific product for a refrigeration system.
3. Compressor capacity (tons) at minimum allowable
evaporating temperature - consult compressor
capacity ratings for this value.
4. Minimum evaporator load (tons) at which the system
is to be operated - most systems are not
required to operate down to zero load but this value
will depend on the type of system. For example,
most air conditioning systems only need to operate
down to 15-25% of full load. However, air conditioning
systems for data processing and “white” rooms,
and most refrigeration systems may be required to
bypass to zero load conditions.
5. Condensing temperature when minimum load
exists - since the capacity ratings of the bypass valves
are a function of condensing temperature, it is vital
that proper head pressure is maintained, especially
during low load operation. As the capacity table indicates,
a condensing temperature of 80°F is considered
the minimum allowable for satisfactory system operation.
See Bulletin 90-30 for information on Sporlan’s
Head Pressure Control Valves.
