Submittal Sheet

VP525A,C PNEUMATIC RADIATOR VALVES
3 75-5544EF
Underheating
If room temperature is lower than the thermostat setting,
check branchline pressure at the valve:
1. No branchline pressure at valve:
a. If heat is present in piping to valve, the valve (or
steam trap) is stuck closed. If valve is stuck, free it
by removing top and operating valve stem manually.
b. If evidence exists of leakage around valve stem,
repack valve (see Packing Replacement section).
c. If stem binding or sticky operation persists, replace
the top and insert assembly (or entire valve).
2. Branchline pressure present: Valve opens when the
branchline is removed. Cap line and check thermostat
operation and calibration. If the valve does not open,
return to step 1.
Overheating
If room temperature is higher than thermostat setting, check
branchline pressure at valve:
1. No or low branchline pressure at valve:
a. Check for air leaks in thermostat branchline.
b. If branchline is OK, cap line and check thermostat
operation and calibration.
2. Branchline pressure present:
a. If branchline pressure decreases when fed to the
actuator, the diaphragm is defective. Replace top
(see Diaphragm Replacement section).
b. Check the Troubleshooting Flowchart (Fig. 4) to
determine that branchline pressure is sufficient for
tight close-off and system pressure is not excessive.
(1) If air pressure is maintained and heating medium
still flows through the valve, the problem is either
a stuck valve stem, or defective seat/molded
plug.
(2) Disassemble the valve to replace these parts
(See Stem and Disc Holder Assembly and/or
Valve Seat Replacement section).
NOTE: Some models do not include a removable
valve seat. Defective seats in these valves
require complete valve replacement.
Fig. 4. VP525A,C troubleshooting flowchart.
C4656B
START
CHECK
THERMOSTAT
CALIBRATION
THERMOSTAT
CALIBRATION
OK
?
END
CALIBRATE
THERMOSTAT
ADJUST THERMOSTAT
SETPOINT
SPACE
TEMPERATURE
± 2 DEGREES
FROM
SETPOINT
?
NO
YES
APPLY 18 PSI
TO ACTUATOR
DOES
VALVE
CLOSE
?
STEM STUCK
OPEN
REPLACE TOP
AND INSERT,
STEM,
OR VALVE
HEATING SYSTEM
PRESSURE TOO
HIGH
REDUCE SYSTEM
PRESSURE
YES
HOT
WATER
OR STEAM
IN PIPES
?
CHECK
HEATING
SYSTEM
DECREASE AIR PRESSURE
TO ACTUATOR TO ZERO
NO
YES
DOES
VALVE
OPEN
?
DISCHARGE
SIDE OF
VALVE HOT
?
REPLACE TOP AND
INSERT, STEM, OR
VALVE
STEM
STUCK
CLOSED
REMOVE
OBSTRUCTION
VALVE
OBSTRUCTED
NO
NO
YES
YES
TOO
HIGH
NO
SEAT WORN REPLACE SEAT
OR VALVE
DISCHARGE
SIDE OF
VALVE HOT
?
YES
NO
YES
YES
NO
END
TOO
LOW
SPACE
TEMPERATURE
± 2 DEGREES FROM
SETPOINT
?