Reliable FX Dry Pipe Valve, Externally Resettable, 2 to 6 in

The Reliable FX is a differential-principle, externally resettable dry pipe valve used as the primary control valve of a dry pipe sprinkler system, for buildings or zones where pipework is filled with air or nitrogen instead of water. Reliable lists a lightweight ductile iron body with compact trim, an external reset that reduces setup and commissioning time, and no need for priming water. Bulletin 360 (April 2026) covers 2 in to 6 in and 165 mm sizes with grooved, flanged or flange x grooved ends.

How the dry pipe valve works

The clapper is held in the set position by pneumatic pressure acting on a larger surface than the incoming water pressure. Reliable states that the upper clapper area is about six times the area exposed to water, so one psi of air or nitrogen offsets roughly six psi of water. When a sprinkler opens and system pressure falls, water pressure lifts the clapper, flows into the system and the alarm outlet, and a lever latches the clapper open until it is reset by hand with the external reset plunger. All sizes can take the Model B1 accelerator (PN 650120001A, ordered separately) to speed the trip time.

Key features from the bulletin

• Ductile iron body and cover, painted; stainless steel clapper; EPDM rubber and aluminium seat; galvanized steel trim.
• External reset on the left of the body; no priming water required.
• Grooved, flanged or flange x grooved ends; vertical installation only.
• cULus Listed, FM Approved, LPCB Approved (EN 12259-3:2000) and CE, as printed in the bulletin.

Technical specifications

Data from Bulletin 360 Tables A to D.

Part number decoding and ordering

The fully assembled part number follows the pattern 65080 X Y Z 00. X is the size (2 = 2 in, 1 = 2-1/2 in, 7 = 76 mm, 3 = 3 in, 4 = 4 in, 6 = 6 in, 5 = 165 mm); Y is the end connection (7 = groove x groove, 8 or 9 or A = flange x groove, B or C or E = flange x flange); Z is the trim, from 0 (no control valve, no accelerator) to 5 (two control valves with accelerator). Specify model, size, ends and trim (fully assembled with or without control valve, segmented or loose). Pressure switches (low air PN 6990006381, alarm PN 6990006382) come only with fully assembled trims.

Installation and commissioning notes

Install to NFPA 13 in a visible, accessible location kept at 40 F (4 C) or above; flow must be up through the assembly. The bulletin warns that heat tracing can leave hardened mineral deposits and that water hammer must be avoided. Set-up involves draining the system, pushing the external reset plunger until it clicks, charging air or nitrogen to Table C values, then slowly opening the main control valve. Service kits hold the seal assembly, cover gasket and grease; seat wrenches are PN 6881702000 (2 in) to 6881706000 (6 in).

Typical applications

Dry pipe systems protect unheated warehouses, loading bays, car parks and cold stores. In Gulf projects they also serve open-sided or unconditioned plant areas. Confirm the design basis and local approval for your site.

Selection and installation notes

A fire protection valve is only one part of a sprinkler system, which must be designed, installed and commissioned by qualified people to the standard and the authority rules that apply to the project. Confirm the size, the pressure rating and the trim configuration against the design, install the valve in the position and orientation in the manual, fit the drain and alarm connections as drawn, test the alarm and the flow before handover and keep the inspection and test records. Check the listing and approvals needed for the project with the authority before purchase.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related items and documents

Pair the FX with the Model B1 accelerator (Bulletin 323). The bulletin is hosted on this page. Seven Star LLC is an independent supplier in Muscat; see the Fire Fighting range or send size, ends and trim for a quotation.

Frequently asked questions

What sizes is the FX dry pipe valve available in?

2, 2-1/2, 3, 4 and 6 in, plus 76 mm and 165 mm. 76 mm, 165 mm and sizes up to 3 in are grooved only.

Does it need priming water?

No. Reliable lists no priming water requirement.

How is the FX reset after operation?

With the external reset plunger on the left side of the valve body; the plunger is pushed in until a click is heard.

What pressure rating applies?

250 psi (17.2 bar) for 2 to 3 in sizes; 300 psi (20.7 bar) for 4 in and 6 in sizes.

Can an accelerator be fitted?

Yes, the Model B1 accelerator, PN 650120001A, ordered separately.