Series PRA/PRAM features two opposing large area frictionless rolling diaphragms. Process pressure is applied to one of the diaphragms; air pressure is applied to the other. Because the air pressure can be maintained with more accuracy than the force provided by a spring, the PRA/PRAM offers greater sensitivity and less variance from set pressure than any thermoplastic pressure regulator previously available. The PRA/PRAM can be used in combination with Plast-O-Matic’s patented Stabilizer which measures downstream liquid pressure and provides continuous feedback control for even greater sensitivity and performance. Molded and machined valves in 1/4″ through 3″ and metric pipe sizes in popular thermoplastic materials with a wide range of connection types. Set range 5-125 PSI. This is a Specialty Custom product; consult factory for availability. Minimum quantities may apply.

I assume you have an expansion tank attached to the cold water line leading into the boiler. I’d check that – if it feels warm all around, it’s membrane is probably faulty and the tank needs to be replaced.

Series UPRS Downstream pressure reducing valve features full shutoff design (pressure will not equalize in a no-flow condition) and the ultimate purity levels, as verified by independent test labs. BCF spigots standard; flare, sanitary, and other connection types available. 20 – 63mm sizes; Kynar 740 body. High purity CDB-16 (8 hour hot / 8 hour cold DI rinse) procedure is standard; clean and double bag in class 100 (ISO 5) clean room. Ultimate purity with excellent flow performance; set pressure range 10-100 PSI. Available with or without isolated pressure gauge.

Accurately reduce and regulate steady or varying inlet pressures and maintain a constant, predetermined maximum outlet set pressure. Offered in spring controlled, air controlled, differential controlled and ultra-pure designs, Plast-O-Matic regulators are consistently recognized as the industry’s top performers for maximum flow with minimal drop-off from set pressure. ½” through 3”; for 4” consult factory.

Series PRD/PRDM is a differential pressure regulator with a port for a downstream pressure sensing line. The sensing line feeds the pressure downstream of the equipment being protected to the top of the spring housing, which assists the spring in keeping the regulator open against the pressure directly at the regulator outlet. When pressure downstream begins to drop (as it would when a filter becomes more and more clogged), the regulator begins to close and becomes fully closed when the differential setting is reached. This assures against overpressure across the equipment. Molded and machined valves in 1/4″ through 3″ and metric pipe sizes in popular thermoplastic materials with a wide range of connection types. Differential set range 5-50 PSI.

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I see screws... can this be opened and cleaned or should I replace this Pressure Reducing Valve entirely? Is there anything else I should check in my diagnostics?

Series PRS patented Stabilizer is used with Series PRA. The Stabilizer reacts to downstream liquid pressure and provides continuous feedback control to the compressed air supply, for even greater regulator sensitivity and performance. This is a Specialty Custom product; consult factory for availability. Minimum quantities may apply.

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Series PRHU Downstream pressure reducing valve features metal ion-free EPDM large area rolling diaphragm, ultra-smooth operation and isolated spring control. BCF spigots in 1/2″ – 3″ or 20 – 90mm sizes; Kynar 740 body and Class 100 clean/double bag procedure standard. Provides highest flow with minimal pressure droop among high purity regulators; set pressure range 10-125 PSI.

Series PR/PRH/PRHM Downstream pressure reducing valve features large area rolling diaphragm, ultra-smooth operation and isolated spring control. Molded and machined valves in 1/4” through 3” (for 4” consult factory) and metric pipe sizes in popular thermoplastic materials with a wide range of connection types. Proven design provides highest flow with minimal pressure droop. While some valves may be limited by size or material, most models provide set range of 10-125 PSI.

If the pressure is below the relief valve setting, the relief valve may be faulty. If the pressure is at or above the relief valve setting, the pressure reducer may be faulty. If the temperature is too high, the relief valve may be a combined temperature/pressure relief which is actuating properly due to temperature extremes. The reason for any such temperature extremes should be corrected.

Accurately reduce and regulate steady or varying inlet pressures and maintain a constant, predetermined maximum outlet set pressure. Offered in spring controlled, air controlled, differential controlled and ultra-pure designs, Plast-O-Matic regulators are consistently recognized as the industry’s top performers for maximum flow with minimal drop-off from set pressure. ½” through 3”; for 4” consult factory.

A few weeks ago, my oil-fired water boiler started continuously leaking water out of the pressure release valve on the top of the unit. I know this is leaking steadily because it drains into a 5gal bucket and I have dumped it twice now. I examined the system and determined that in order to keep leaking, water must be fed into the system from somewhere. So I looked up this Pressure Reducer Valve and determined its function - filling the system when water pressure gets low. I also read online that this valve can malfunction and let in too much water pressure causing this sort of leak.

Series UPR Downstream pressure reducing valve features non-shutoff elastomer-free design (pressure will equalize in a no-flow condition) and the ultimate purity levels, as verified by independent test labs. BCF spigots, flare, sanitary, and other connection types available. 1/4″ – 2″ or 20 – 63mm sizes; choice of Kynar 740 or PTFE body. High purity CDB-16 (8 hour hot / 8 hour cold DI rinse) procedure is standard; clean and double bag in class 100 (ISO 5) clean room. Ultimate purity with excellent flow performance; set pressure range 5-100 PSI.

If you don't really have a solid understanding of what you are doing, a licensed boiler service technician can be well worth the cost of the service call.