Installation
Valve Requirements
Page 8
MDE-4645B Model 52 Pressure Regulator Valve Installation/Parts Manual · August 2019
Valve Requirements
The requirements of the Model 52 Pressure Regulator Valve are as follows:
• It must conform with all building/fire codes, all Federal, State, and Local codes, National
Electrical Code (NFPA 70), NFPA 30, Automotive and Marine Service Station Code
(NFPA 30A), and NFPA 395 codes and regulations.
• It is designed to operate in fueling systems that have a maximum pressure of 50 psi.
• Installation must include thermal expansion relief valves. Thermal expansion can cause
pressures in the system greater than 50 psi and can result in failure of the valve and loss of
product to the environment.
• Installation must include a solenoid valve positioned adjacent to the shutoff valve at the
tank. Its purpose is to prevent loss due to failure of the downstream piping or the system.
• Installation must locate the shear groove at the same level as the top of the concrete island
+1/2-inch (13-mm).
• Installation must include shutoff or gate valve to close the system and prevent product loss
when the equipment utilized in the fueling system downstream from the AST is being
serviced or replaced.
Refer to
on
, and
on
Troubleshooting
Refer to the parts drawing
on
for item reference
s.
Problem
Possible Cause
Product leaking out valve vent and/or pumping unit
vent.
• Diaphragm (11) has failed and an obstruction in the valve is
holding open the poppet complete (12).
• Gasket (7) and Diaphragm (11) have failed.
• Pressure Relief Valve assembly (4) and Diaphragm (11)
have failed.
No delivery when pump is turned on.
• Failed Diaphragm (11).
• Valve vent blocked or shipping plug never removed.
When a 52 valve is installed at the pump, never install a vacuum anti-siphon valve
at the top of a tank. An electric solenoid valve is required.
CAUTION
