Product manual

16 IOMM ACR/AGR-1
totaling 10 x 3.05 psi (or 10 x 2.2) and still satisfy the objective of delivering solid liquid to the
expansion valve.
In calculating the pressure losses, or gains, note that each foot of rise in a liquid line results in
approximately 0.5 psi loss. Thus a 10 foot rise represent 5 pounds per square inch loss in refrigerant
pressure, or the equivalent of 1.6ºF subcooling with R-22. Total line losses will include values for line
friction, equivalents for valves and elbows and pressure losses from manufacturers’ catalogs for
driers, solenoids, sight glasses, etc.
In estimating condenser subcooling, note that saturated condensing pressure should be read, or
estimated, at the same point in the system where the liquid refrigerant temperature is obtained. That
condensing pressure is not the discharge pressure read at the compressor outlet. Because it is less,
the net value of subcooling will be lower than might otherwise be assumed.
Where rises in liquid lines result in a 0.5 psi loss per foot of lift, a drop in the liquid line results in a rise
in the refrigerant pressure. A substantial drop in the liquid line can assure the existence of pure liquid
at the valve. If it is a substantial increase because of a large drop, the expansion valve selection must
be re-checked to confirm that the valve to be used is not radically oversized.
Liquid Lines from Condensers to Receivers
Receivers in a refrigerant system have both liquid and gas contained within the same vessel. In air-
cooled condenser applications, the condensing temperature can change rapidly resulting in the
requirement for more liquid at a lower temperature and pressure to be introduced into the receiver.
In order for this flow of lower temperature and pressure of liquid refrigerant to enter the receiver, 1) the
receiver must be located below the condenser outlet with no restrictions in the line, and 2) the liquid
line connecting the condenser and the receiver must be sized for a maximum velocity of 100 fpm.
Piping sizes for this are shown in the ASHRAE tables.
Note: If the interconnecting piping described above contains a Seasontrol type head pressure
control valve representing a restriction in the liquid line, a separate vent from the top of the
receiver to the discharge line entering the condenser is required.
Liquid Line Components
To assist in laying out and specifying split systems, the following recommended (or equal)
components can be used.
Table 9, Liquid Line Components
Sporlan Part Number Shown - (Equivalents Are Acceptable)
Unit
Model
System
Nom.R-22
Tons
(mbh)
Filter
Drier
Solenoid
Valve
Sight
Glass
Expansion
Valve
Unit Conn.
In/Out
ACR 070A Circuit #1 31.6 (379) C-967 E25S270 SA-17S OVE-30 7/8-1-3/8
Circuit #2 36.3 (436) C-967 E25S270 SA-17S OVE-40 7/8-1-3/8
ACR 075A Circuit #1 & #2 36.3 (436) ea. C-969 E25S290 SA-19S OVE-40 1 1/8-1-3/8
ACR 080 Circuit #1 & #2 40.0 (480) ea. C-969 E25S290 SA-19S OVE-40 1 1/8-1-3/8
ACR 090A Circuit #1 40.8 (490) C-969 E25S290 SA-19S OVE-40 1 1/8-1-3/8
Circuit #2 49.1 (589) C-1449 E25S290 SA-19S OVE-55 1 1/8-1-3/8
ACR 100A Circuit #1 & #2 49.1 (589) ea. C-1449 E25S290 SA-19S OVE-55 1 1/8-1-3/8
ACR 110A Circuit #1 49.1 (589) C-1449 E25S290 SA-19S OVE-55 1 1/8-1-3/8
Circuit #2 57.4 (689) C-1449 E25S290 SA-19S OVE-70 1 1/8-1-3/8
ACR 120A Circuit #1&#2 57.4 (689) ea. C-1449 E25S290 SA-19S OVE-70 1 1/8-1-3/8