The BERMAD BC-750-66-P is the Buildings & Construction variant of the 750-66 hydraulic level control valve, designed for automatic filling and level maintenance of reservoirs, rooftop tanks, pressure-breaking tanks, and fire protection water storage. The "BC" prefix denotes a pre-configured package optimized for building services: ductile iron Y-pattern globe body with fusion-bonded epoxy coating (RAL 5005 blue, NSF and WRAS approved), NBR diaphragm, and a 4-way bi-level float pilot with stainless steel rod and plastic float. No electrical power or compressed air is required — the valve operates entirely on line pressure from the supply main.

How does line-pressure-driven actuation work without external power?

The BC-750-66-P uses a double-chamber diaphragm actuator connected hydraulically to the float pilot. When the reservoir level falls below the low-level stopper on the float rod, the 4-way pilot directs upstream line pressure into the upper chamber of the actuator while venting the lower chamber — the diaphragm pushes the valve plug downward, opening the main valve. When water rises to the high-level stopper, the pilot reverses: line pressure enters the lower chamber while the upper chamber vents, driving the plug upward against the seat for drip-tight shut-off. Because line pressure powers both opening and closing strokes (rather than a spring-close design), the valve operates reliably even at very low inlet pressures — BERMAD recommends consulting the factory below 0.7 bar (10 psi) and above 10 bar (150 psi) inlet for float-piloted configurations. The non-slam closure characteristic prevents water hammer on shut-off.

Setting the level control range

Two adjustable stoppers slide along the stainless steel float rod to define the operating band. The minimum distance between high and low stoppers is 15 cm (6 in), the maximum is 54 cm (21 in). An extension rod adds 56 cm (22 in) of reach for deeper tanks — a second extension requires an additional counterweight on the float arm. The valve remains closed at all intermediate levels between the two stoppers (last-position pilot), meaning it cycles only at the defined high and low setpoints rather than hunting continuously. For tanks requiring two distinct fill levels (e.g., domestic and fire reserve volumes in a shared tank), the bi-level float configuration provides independent high-level shut-off for each volume without a second valve.

Materials built for potable water and fire protection

The ductile iron body carries a fusion-bonded epoxy coating certified to NSF-ANSI 61 and NSF-ANSI 372 for drinking water contact, with WRAS approval for the UK market. Internal components — seat ring, stem, and fasteners — are stainless steel or tin bronze, selected for corrosion resistance in chlorinated water. The NBR diaphragm is nylon fabric-reinforced for tear resistance over extended cycling. The complete valve is in-line serviceable: the double-chamber actuator unbolts as a single unit, exposing the seat and diaphragm without removing the valve body from the pipeline. Full certifications include EN-1074 (water supply valves), AS 5081 (Australian water standard), and ISO 9001 manufacturing quality. For applications requiring throttled low-flow control rather than on/off operation, BERMAD offers an optional V-port throttling plug for stable flow modulation at very low opening positions.