COMPACT WIDE-RANGE PRESSURE REGULATORS

1 COMPACT WIDE-RANGE BULLETIN 25-94E. PRESSURE REGULATORS Type A8A, A81, A82. Type A8a, a81, a82. Ports 9mm (3/8 ) to 66mm (2 5/8 ) Nom. FEATURES. Dual spring for wide range PRESSURE set points Pilot operated for close control at desired set point Excellent regulation at light loads Interchangeable capacity cartridges Inlet, outlet or differential regulator functions Low PRESSURE drop Few moving parts Long life stainless steel diaphragms (no bellows to fail). Variations available for pilot electric shut off and pilot electric wide opening PRESSURE control Manual opening feature All service from the top Sweat in place without disassembly Furnished with access fitting October 2006. UL listed (except 50 Hertz versions) Installation, Service and Parts Information SPECIFICATIONS. Design PRESSURE (PS): bar (450 psig) plug, and defines the Port Size; 3) A pilot adapter, which defines the valve Range: 250mm hg to bar (10 hg to 400 psig) function and onto which the Pilot Solenoids providing either the S or DESCRIPTION B feature are added as required; 4) The bonnet, containing the Range These ductile iron bodied REGULATORS , with brazed copper couplings, will Spring and adjustment screw, which mechanisms are set for the value of modulate the flow of refrigerant vapor or liquid to maintain a constant PRESSURE which the valve is to maintain.

2 PRESSURE at a control point regardless of fluctuations in load or ambient This unique modular design allows the regulator to be soldered into the conditions, or alternate diversions for flow. Models are available in line without disassembly, yet provides full access for disassembly, clean . com binations of connection sizes, port sizes, functions and features as ing and servicing from the top only. Interchangeable capacity cartridges de signated by the model code, for application in a wide variety of control facilitate flow revisions should an undersized or oversized condition be functions on industrial, commercial and air conditioning systems. (3) created, while pilot adaptors can be changed out to add features or even control functions are available: Inlet, Outlet and Differential PRESSURE change functions. Thus, retrofitting for additional evaporator capacity, control.

3 (2) control features can be added by incorporating pilot solenoids; heat reclaim, or holdback for hot gas defrost is simple and requires no either Electric Shut off (S) or Electric Bypass (also called wide Opening) pipe line revisions under most circumstances. (B). All A8 series REGULATORS for inlet and outlet functions feature the wide range The valves are an integrated assembly of (4) modules: 1) A body, which PRESSURE setting, 250mm Hg to bar (10 VA. to 400 psig). REGULATORS contains no moving parts, but is ordered to suit a particular connection for differential function have a range of 0 to bar (0 to 120 psi). size; 2) A capacity cartridge, which contains both piston and modulating FIELD ADJUSTABLE. STAINLESS STEEL SET-POINT BONNET AS SHOWN. DIAPHRAGM ATTACHED TO ADAPTER. SEPARABLE. PISTON. MANUAL. OPENING STEM INTERCHANCEABLE. CARTRIDGE TO CHANGE. 1/4 SAE FLARE CAPACITY.

4 ACCESS FITTING ALL WEAR PARTS. INLET PRESSURE SERVICABLE. FROM TOP ONLY. CONTOURED PLUG. MULTIPLE THREE BASIC BODY. CONNECTIONS. SIZES. A8A, A81 Assembly (A81 Body Shown) A82 Assembly FLO-CON. 050263. 1. I S O 9 0 0 1-2 0 0 0 C E R T I F I E D. PURPOSE INSTALLATION. These valves will modulate to maintain a PRESSURE as set for in the field, On the Types A8A, A81 and A82 Series REGULATORS , the proper direction in spite of fluctuations in load, changes in ambient, changes in available of flow is designated by an arrow cast into the side of the valve body, refrigerant flow paths, and other operating variances. Appropriately pointing from inlet to outlet. sized, these valves will modulate the flow of liquid or vapor, high side or low side in a wide variety of system arrangements used in industrial, The regulator can be mounted in a horizontal or vertical pipe line with direction commercial and air conditioning installations.

5 A particular inlet regulator of flow as described above. As with all PRESSURE REGULATORS , these COMPACT can be applied to control evaporator, condensate, discharge or defrost REGULATORS can control flow in this normal direction only. If a change in system relief PRESSURE ; a particular outlet regulator can be applied to control operating conditions causes the outlet PRESSURE to rise sufficiently above the crankcase, receiver or hot gas bypass; or a differential regulator can be inlet PRESSURE , the Main Valve Assembly may be blown down from its seat and applied to maintain oil receiver PRESSURE , or discharge differential, or liquid reverse flow can occur. This is often accompanied by a clicking noise. line differential PRESSURE . Each port size will have a specific maximum capacity at full opening corresponding to the available or sensible PRESSURE Protect the inside of the regulator from moisture, dirt, chips and solder beads difference under which it will operate, for each of these applications.

6 During installation. These COMPACT REGULATORS may be soldered into the line The prefix A8 defines a body or assembly style, in this case a direct con without disassembly if reasonable precautions are taken. The flame from the nected, stubbed, modular assembly, PRESSURE regulator. The soldering torch should be directed away from the valve body to avoid excessive basic designations are A8A, A81, and A82, which, with no other suffix, heat build up which could possibly damage some of the internal parts. As an define by default Inlet PRESSURE REGULATORS in the (3) available body sizes. additonal precaution, a wet cloth should be wrapped around the regulator body To complete the purchasing specification for an inlet regulator with to dissipate some of the heat during the soldering operation. no additional features, the Port Size and Connection Size must yet be determined.

7 For an Inlet PRESSURE Regulator, as the valve's inlet PRESSURE PRINCIPLES OF OPERATION. increases even marginally above the set point the valve tends to open, (Referring to Valves as shown in Fig. 3 9) In all cases, a throttling point increasing flow and reducing inlet PRESSURE . As operating con ditions serves to increase or reduce the rate of delivery of the pilot stream change and the inlet PRESSURE tends to drop, the valve's port closes and from the upstream side of the valve to the space on top of the piston, the inlet PRESSURE will tend to rise. In this fashion the valve continually from which it is bled to the downstream via both a tiny hole through the adjusts its available flow area in response to flow conditions to maintain piston and the clearance between piston and bore. An increased pilot a practically constant inlet PRESSURE . stream flow increases the PRESSURE on top of the piston which pushes The solenoid features can be designated for these inlet PRESSURE reg the modulating plug down.

8 Conversely, a decreased pilot stream flow ulators by adding the appropriate suffix, thus A8 S for Inlet Regulator reduces the PRESSURE on top of the piston and permits the closing spring with Electric Shut off and A8 B for Inlet Regulator with Electric wide to push the modulating plug up, reducing the flow area available at the Opening. port. The pilot portion of the valve is devoted to administering this pilot stream flow, thus effectively controlling the main valve opening. The valve The suffix O defines a regulator whose function is to modulate flow to function (inlet, outlet, differential) is deter mined by the PRESSURE condition maintain a constant Outlet or Downstream PRESSURE . This valve function to which the pilot aspect of the valve responds. requires that an external field installed connection be made between the pilot equalizing connection and the downstream pipe, thus the O FOR AN INLET PRESSURE REGULATOR: The inlet PRESSURE is designation is always accompanied by an E for externally equalized applied via Passage N to the underside of the #10 Diaphragm at Chamber (A8 OE).

9 The function now is to open and permit higher flows when outlet P. Considering a valve that is initially closed, as the inlet PRESSURE rises, PRESSURE tends to drop, and to close and reduce flow when outlet PRESSURE the Diaphragm exerts a force upward against the #5 Range Spring. When tends to rise. In this fashion the valve is continuously adjusting its opening that force developed by the inlet PRESSURE is high enough, it will equal the to maintain downstream PRESSURE practically constant. spring force at that point of adjustment and the diaphragm will rise off The outlet PRESSURE REGULATORS are available with the S feature, thus the its seat and permit flow from the upstream to Chamber G, thus raising designation A8 OES defines an Outlet PRESSURE Regulator with Electric the PRESSURE on top of the piston, causing the Modulating Plug H to move Shut Off, which will maintain constant downstream PRESSURE when the down, and opening the port.

10 Should the system conditions cause the coil is energized, and close tightly when the coil is de energized. upstream PRESSURE to decrease, the Diaphragm will return to a position The suffix L is added to designate a Differential PRESSURE Regulator. closer to the Pilot Seat, reducing the pilot stream flow, and allowing This valve function senses both Upstream and Downstream PRESSURE the PRESSURE in Chamber G to bleed away somewhat, which permits the and modulates to maintain the difference, practically constant. Thus the closing spring to move the modulating plug up, thus closing the port. regulator responds to a rise in that PRESSURE difference by opening the FOR AN OUTLET PRESSURE REGULATOR: The external, field port, and responds to a drop in that difference by closing the port. An A8 L instal led connection is run from the Fitting J to the appropriate space is a Differential PRESSURE Regulator.