Page 1
275AP/APF SERIES HIGH-SIDE FLOAT VALVES
Ø4.50 [114.3]
Ø3.75 [Ø95.3]
BC
Ø0.50 [Ø12.7]
(6) HOLES
2-1/2" PIPE
X 2-1/2" LONG
2.42 [61.5]
1.20 [30.4]
VALVE
CL
FLANGE
FACE
9.13 [232.0] 275AP/AF
9.30 [236.2] 275APF
1.88 [47.6]
MOUNT'G FLANGE, SEE FIGURE 4
1/2" FPT CONNECTION
ABOVE VALVE CL
275AP/APF
275AF
0.56 [14.3]
VALVE
CL
FLOW DIRECTION
7.19 [182.6]
4.81 [122.2]
3/4" FPT
9.38 [238.1]
12.38 [314.3]
3/4" FPT
1/2" FPT
4.13 [104.8]
CHAMBER
Ø4.50 [Ø114.3]
Visit us at: www.haphillips.com or e-mail us at: info@haphillips.com
275AF SERIES LOW-SIDE FLOAT VALVES
BULLETIN 275AP-SB13-01
SERVICE BULLETIN
VALVES • VESSELS • SYSTEMS • CONTROLS
System drawings shown in this bulletin are for illustration purposes only. Refrigeration systems should only be serviced by a qualified technician.
Always observe proper safety procedures when servicing a refrigeration system. For more information see the latest reversion of Phillips Safety
Bulletin SGRV.
GENERAL INFORMATION
Pressure Rating: 300 psig (21 bar, gauge)
Maximum Operating
Pressure Differential: 275AF: 20 psi (1.4 bar)
275AP/APF: 250 psi (17 bar)
Temperature Rating: -20°F to 240°F
(-29°C to 116°C)
The 275AP/APF valves are high-side float valves which act as
pilot mechanisms for separate pilot-operated valves, such as
the Phillips 700H. The 275AP valve is used for ammonia
applications and the 275APF is used for halocarbon
applications.
The 275AF valves are low-side float valves that control
compressor crankcase oil level.
All the valves in this family open on a drop in liquid level and
throttle flow with a “needle and seat” mechanism. A 1/2” FPT
connection serves as an outlet connection for the 275AP/APF;
the same connection serves as an inlet for the 275AF.
Figure 1: 275AP/APF/AF Valve without Chamber
INSTALLATION INSTRUCTIONS
The 275AF/AP/APF valves are available without a chamber
(Figure 1), with a cast iron chamber (Figure 2) or with a welded
steel chamber (Figure 3). An optional mounting flange is
available for mounting the valve without a chamber (Figure 4).
The valve should always be oriented such that the 1/2" FPT
connection is toward the top of the valve and the front face is
vertical. This will ensure that the float moves appropriately with
changes in liquid level.
The 275AP and APF valves are used as pilot float valves to
control a 700H series valve. The piping arrangement in Figure
5 shows a number of important details:
The float level should be at least 18 in. above the 700H
valve.
The pilot line MUST be either 3/8” OD copper tubing
(halocarbon applications) or 1/4” nominal pipe (halocarbon
or ammonia).
The pilot line should include a shut-off valve, pressure
gauge and gauge valve for troubleshooting. (See
Troubleshooting section, later in this bulletin.)
Figure 2: 275AP/APF/AF Valve with Cast Iron Chamber
275AP-SB13-01 1
Page 2
Figure 3: 275AP/APF/AF Valve with Steel Chamber
27.88 [708.0]
15.88 [403.2]
7.88 [200.0]
8.25 [209.6]
Ø6.63 [168.3]
4.50 [114.2]
3/4" FPT
1/2" FPT
LEVEL EYE ®
3/4" FPT
(6) 7/16-20 NF
0.63 [15.9]
Ø2.91 x .34DP
SOCKET
Ø3.75 [Ø95.3]
BC
Ø4.50 [114.3]
TO LOWER
PRESSURE
VESSEL
P
18 in.
MIN.
CONDENSER
DRAIN
UPPER EQ LINE
LOWER EQ LINE
(DO NOT TRAP
ON NH3)
MANUAL BYPASS
PILOT LINE
1/4” NOMINAL IPS
700H SERIES
PILOT
OPERATED
VALVE WITH
CLOSE-COUPLED
STRAINER
275AP/APF PILOT
FLOAT VALVE
UNION
OIL RECEIVER / STILL:
AT LEAST 2 FT HIGHER
ELEVATION THAN CRANK
CASE FOR GRAVITY FEED;
CAN BE AT SAME ELEVATION
AS CRANKCASE IF AT HIGHER
PRESSURE.
275AF: CHAMBER
EQUALIZED TO
CRANKCASE
275AF: CHAMBER
EQUALIZED TO
CRANKCASE
2 FT.
Figure 4: Optional Mounting Flange
Figure 5: 275AP/APF Piloting 700H Valve
Figure 6: 275AF Maintaining Oil Levels in Multiple
Compressor Crankcases
275AP-SB13-01 2
The 275AF valves may be used to maintain the oil level in one
or more compressor crankcases (Figure 6). Note that if the oil
reservoir level is less than 2 feet above the crankcase level, it
should be pressurized 5 to 20 psi (0.3 to 1.4 bar) higher than
the crankcase.
REPLACEMENT PARTS
Basic replacement parts are illustrated in Figure 7 and listed in
Table 1.
When contacting Phillips for replacement parts, have the
complete valve model and serial number (shown on the valve
nameplate) available to ensure you receive the correct
components. For example: “275APF-BZA” is a complete valve
model, and “990123” or “E-12345” are complete serial
numbers.
SERVICE INSTRUCTIONS
Lever pin / float block removal and replacement: If it is
necessary to remove the lever pin (411) and float block (230Z)
during servicing, first cut one end of the pin flush with the valve
body. Then either pull the pin out with pliers, or carefully drive it
out with a punch. Retain the spacers (11S) for re-assembly.
After re-assembly, peen the lever pin to retain in place and
check for free movement of valve components.
Needle and seat replacement: The needle and seat bushing
are lapped in the factory to create a matched set. If either the
needle or seat bushing show signs of wear or damage, both
parts must be replaced. To inspect or replace the needle and
seat perform the following steps.
1. Remove the lever pin and float block as described above.
2. Remove the old seat bushing and install a new one using
PTFE tape or other pipe sealant on the threads.
3. Remove the old needle from the adjusting nut (204E), lock
washer (55), and lock nut (224). Reassemble the nut and
washer loosely on the new needle.
4. Insert the new needle into the new bushing. Install the
float block / float assembly (without spacers) loosely in the
valve body with the lever pin. DO NOT PEEN THE LEVER PIN
AT THIS TIME.
(Continued on next page)
Page 3
Figure 7: 275AF/AP/APF Valve Assemblies
Description
Part No.
Chamber, Cast Iron (Not shown)
299A
Chamber, Steel (Not shown)
B-10985
Valve Body
270A-VB
Gasket*
73
Cap Screw (6)
325
Float Ball, 275AF/275AP
220A
Float Ball, 275APF
220
Float Rod, 275AF/275AP
343A
Float Rod, 275APF
343D
Float Block
230Z
Float Nut
322
Nut
(275APF - Qty 1, 275AF/275AP - Qty 2)
224
Lock Washer
(275APF - Qty 3, 275AF/275AP - Qty 4)
55
Adjusting Bolt
369
Link
431
Lever Pin
411
Spacer
11S
Roll Pin
211-1/2
Adjusting Nut
204E
Needle and Seat Bushing*
(Must be replaced as matched set)
262403S-1/16
262403S-5/64
262403S-3/32
262A403A-1/8
262A403A-3/16
Mounting Flange (Not shown)
298A
*Spare Parts Kit
(Includes Gasket and Needle and Seat
Bushing)
K275AP1
(1/16”, 5/64”, 3/32” orifice)
K275AP2
(1/8”, 3/16” orifice)
0.16 [4.1]
0.09 [2.3]
TO SET
NEEDLE
TRAVEL,
ADJUST
BOLT-HEAD
CLEARANCE
FLOAT SHOULD STAND
JUST ABOVE HORIZONTAL
WHEN NEEDLE IS SEATED
220A
322, 55
343A
270A-VB,
325
73
SEAT
BUSHING
NEEDLE
224, 55
204E
431
230Z
411, 11S
211-1/2
324, 55
369, 324
220
275AF & 275AP
275APF
270A-VB,
325
73
343D
55
Table 1: Replacement Parts
the bushing (Figure 8). Tighten the lock nut to secure needle
position.
7. Remove the lever pin and pull the needle from the
bushing. Reassemble the float block to the valve body using
the lever pin and spacers (11S) to ensure the float block
(230Z) is centered on the link (431).
8. Peen the lever pin to retain in place and check for free
movement of the mechanism.
Figure 8: Needle Adjustment
9. With the needle fully seated in the bushing, check to make
sure there is approximately 0.16” (4mm) clearance between
the adjusting bolt head (369) and the valve body. A #20 drill bit
may be used to check this clearance. (See Figure 9.) Setting
the bolt head clearance ensures 0.09” (2mm) of needle travel
when the float drops due to low liquid level.
10. Be sure the lock nut (324) is tightened against the float
block and the entire mechanism pivots smoothly before reinstalling the valve.
Figure 9: Final Adjustment
SERVICE INSTRUCTIONS(Needle & seat replacement, cont’d)
5. Secure the valve body so the float is approximately
horizontal. Turn the needle in or out of the adjusting nut until
the float is horizontal when the needle is seated in the bushing.
6. Then screw the needle ½-turn into the adjusting nut so the
float is slightly above horizontal when the needle is seated in
275AP-SB13-01 3
Page 4
TROUBLESHOOTING
(2) Pressure Gauge reads:
Approximately Downstream Pressure
Approximately Condensing Pressure
(1) Condenser Liquid Level is:
T
o
o
h
i
g
h
The pressure indicates that the 275AP is closed (as it
should be). Therefore the 700H may be closed due to a
malfunction. Check if the 700H is stuck partially or
completely closed by dirt/debris, or if the strainer is blocked.
Other possibilities: Operating conditions may have changed
so that (1) The 700H cannot open fully due to too strong
spring, or (2) the 700H metering plug does not have
sufficient capacity. Contact Phillips to resolve these issues.
The pressure indicates the 275AP is open (it is supposed to
be closed). Therefore the 700H is being signaled to close.
Check if 275AP float is stuck in low position, or if dirt/debris
is keeping the needle from seating.
T
o
o
l
o
w
The pressure indicates the 275AP is closed (it is supposed
to be open). Therefore the 700H is being signaled to open.
Check if the 275AP is stuck in the closed position. See
“Float Valve Only: valve does not open” Troubleshooting
Tips, above, to resolve the problem.
The pressure level indicates the 275AP is open (as it should
be). Therefore the 700H is open due to malfunction. Check if
the 700H is stuck partially or completely open by dirt/debris,
or the spring may have broken.
Other possibilities: (1) The 700H piston or body may have
worn, permitting blow-by that prevents the pressure above
piston from rising sufficiently to close the valve. (2)
Operating conditions may have changed so that the 275AP
does not have sufficient capacity to close the 700H. Contact
Phillips to resolve these issues.
Condensing
Pressure
Downstream
Pressure
P
The 275AP opens
when the liquid level
drops.
The pressure above the
piston increases when
the 275AP opens.
This closes the 700H.
275AP
700H
Liquid
from
Condenser
Liquid
Out
Strainer
Spring
Whether it is operating as a 275AP/APF high-side float (Figure 5) or as a 275AF low-side float (Figure 6), the valve opens when the
liquid level drops. The operation of the 275AF will be covered first, because understanding its possible malfunctions serve as a
foundation for troubleshooting the 275AP/APF pilot float valve.
Float Valve Only (275AF)
Problem: Valve does not close fully at high liquid level.
Causes/Solutions:
Float rod bent or interference with float movement: If the valve
was supplied without a chamber (299A), the float rod (343A,
not on 275APF valves) may have been bent in shipping. It is
also possible that the valve was installed in a non-standard
chamber that does not allow full float movement. CAREFULLY
bending the float rod a small amount may correct this problem.
Jammed or worn linkage parts: Examine float and needle
movement. Verify that parts move freely and without excessive
play. Check for excessive float block (230Z) and/or lever pin
(411) wear. Remove any debris, replace worn or damaged
parts.
Needle/seat damage or debris present: Remove lever pin and
float assembly. Be careful not to disturb the setting of the
needle and the adjusting nuts. Examine needle and seat
bushing for damage and debris. A worn or damaged needle/seat
should always be replaced with a matched set from the factory.
Hole in float ball: Liquid refrigerant leaking into the float will
prevent it from rising properly with changes in liquid level.
Warming the float will cause any refrigerant inside it to
vaporize. Observe any vapor leakage from the float to confirm
a leak. To replace a defective float, unscrew the float. (Be
careful not to disturb the positions of the nuts (322, 324).)
Install new float snugly, again without disturbing the nut
positions.
Problem: Valve does not open at low liquid level.
Cause/Solution:
Jammed needle or worn linkage parts: Inspect valve as
described above. Repair or replace parts as needed.
Table 2: Troubleshooting The 275AP & 700H
Pilot Float Valve with 700H Valve (275AP/APF)
Figure 9 shows schematically how the 275AP/APF and 700H
valves operate together. This is very similar to the arrangement
shown in Figure 6.
As the liquid level rises in the chamber, the float rises and the
needle shuts off flow to the 700H. The pressure above the
700H piston drops and the piston rises due to pressure
underneath, opening the valve port and allowing flow.
Conversely, as the liquid level drops, the 275AP opens and
pressure above the piston rises, closing the 700H port with
spring-assist.
Match the condenser condition (liquid high or low) with
pressure gauge reading (condensing or downstream pressure)
and note the possible causes given in Table 2.
Figure 9: Schematic of 275AP/700H Operation
H. A. Phillips & Co.
770 Enterprise Avenue
DeKalb, IL 60115 U.S.A.
Phone: (630) 377-0050
Fax: (630) 377-2706
275AP-SB13-01 4
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