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Technical Specification
  
ServiceLiquids
Size3/4"
ConnectionNPT
Max. Inlet Pressure (psig)300
Design Pressure300 PSIG @ 180˚F
Temperature Rating180˚F @ 300 PSIG
Material Specification
  
BodyBronze
SeatBronze
DiscEPDM
10691-13-N-3-T
QTY :
Product Overview
The 10691-Series Back Pressure & Relief Valves relieve upstream pres sure in a variety of processes. 10691-Series has a soft elastomeric disc for tight shut-off. This valve automatically maintain desired maximum pressure in a vessel or system by relieving excess pressure into lower pres sure re turn line or to atmosphere. Ideally suited for use as pump bypass control valve by maintaining constant pump discharge pressures. Used as a continuously operating valve or for protection against intermittent over pressure conditions.

The 10691-Series Back Pressure Relief Valves are used in the following applications :
• Water pump bypass for irrigation, sprinkler systems on golf courses, fountains and fire protection systems.
• Fuel oil pump bypass on commercial systems or large residential systems.

NOT TO BE USED ON STEAM.
Features

• 10691 Series has EPDM Seat for tight shut-off (1/2” - 1”)
• Four Springs – easily interchanged to cover pressures from 1 to 300 PSIG
• Heavy-duty bronze valve body

How It Works

The Relief Valve is actuated by the system pres sure on the inlet side of the valve. Valve loading is provided by a spring. The adjustment is done by removing the cap and rotating the screw clockwise or counter-clockwise. Spring load balances against the opening force of the up stream (or re lief) pressure. Valve will open at the slightest increase in pressure above the spring set point, and will close when the excess pressure has been relieved.

The higher the system pressure is above the relief set point pressure, the more flow the valve will pass. It is therefore typical to specify the maximum capacity of a back pressure relief valve at 10% and 20% over set pressure.

Pressure Adjustments
To adjust set pressure of valve, remove top cap, loosen lock nut and adjust pressure by rotating adjustment screw. Rotating the screw clockwise increases the compression on the spring thereby increasing the set pressure. Rotating the screw counterclockwise lowers the set pressure. Tighten the lock nut and replace top cap and gasket.
Selection / Sizing / Capacities
The Relief Valve remains closed until the Set-Pressure is reached. When the Set-Pressure is met or exceeded, the spring will compress, allowing the valve to open and flow to occur. It is standard practice to publish flow values at 10% and 20% over the Set-Pressure.

Example:
A 1” valve set at 50 PSIG will pass 3.1 GPM if the system pressure exceeds the set point by 20%.

The 10691 Series Relief Valve water capacities at inlet pressures of 10% and 20% over Set-Pressure:
Options

10691-Series Spring Selection Table

Dimension and Weights