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, Sta
te, and Local codes, National
Electrical
Code (NFPA 70), NFPA 30, Automotive and Marine Servi
ce Station Code
(NFP
A 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 expansi
on can cause
pre
ssures in the system greater than 50 psi and can result in failure of the valve and loss
of
p
roduct to the environment.
• Installation must include a solenoid valve positioned adjacent to the shutoff valve at t
he
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 lo
ss
when the equipment utilized in the fueling system downstream from the
AST is bein
g
serviced or replace
d.
Refer to Figure 3-1 on page 9, Figure 3-2 on page 9, Figure 3-3 on page 10, and Figure 3-4 on
page 10 for additional requirements.
Troubleshooting
Refer to the parts drawing Figure 4-1 on page 12 for item references.
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
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