Ball Valves vs Gate Valves — 15mm, 22mm, and 28mm Isolation Valves for UK Plumbers

Ball Valves vs Gate Valves — Choosing the Right Isolation Valve for Every Plumbing Job

Whether you're isolating a washing machine supply, draining a central heating circuit, or replacing a stopcock on the main service pipe, choosing the right valve matters. Ball valves, gate valves, and isolating valves each have a role on a domestic installation — understanding when to use which avoids call-backs and keeps your work WRAS-compliant.

Ball Valves (Lever Ball Valves)

A lever ball valve uses a quarter-turn action to open or close a drilled brass ball inside the body. With the lever parallel to the pipe, flow is fully open; rotate 90° and the port is completely blocked. Key advantages:

• Full bore flow — no restriction when open, which matters for boiler feeds and supply mains
• Quarter-turn operation — visible open/closed position at a glance; valve status is immediately obvious to the next engineer
• Minimal internal wear — the ball seats against PTFE washers with no thread to degrade
• Suitable for service isolation — recommended for isolation under Building Regulations G3 (unvented hot water) and for gas service valves (yellow handle variant required for gas)

Lever ball valves come in compression-fit ends for standard copper pipe. The red handle is the standard water supply colour code. Available in 15mm for appliance feeds and 28mm for mains supply isolations where gate valves were previously used.

Gate Valves

A gate valve uses a rising or non-rising spindle to lower a wedge (the "gate") into the flow path. Multi-turn operation (typically 5–8 full turns) closes the valve. Historically the default choice for heating circuits, gate valves remain common on older installations:

• Use on heating circuits — gate valves are acceptable for radiator circuits, indirect cylinder feeds, and pump isolation on vented systems (Part L compliance)
• BS 5154 / WRAS approved — the Embrass Peerless brass range is manufactured to BS 5154 and carries WRAS approval for potable water applications
• Not suitable for gas — only use BS 6400-certified lever ball valves (yellow handle) on gas isolation points
• Full bore design — like ball valves, a fully open gate valve offers minimal flow restriction

Sizes 15mm, 22mm, and 28mm cover the full range of domestic copper pipework: 15mm for individual radiator feeds and appliance connections, 22mm for zone valve inlets and cylinder supplies, and 28mm for boiler primaries and main trunk feeds.

Isolating Valves (Service Valves)

Chrome-plated isolating valves (also called service valves or mini-isolators) are quarter-turn valves designed for under-sink, under-toilet, or in-wall installations where a small profile matters. They accept a flat-head screwdriver or slotted lever rather than a full-size handle:

• Under-basin and under-WC cistern — 15mm service valves on the hot and cold tails allow appliance swap-out without shutting off the full system
• Washing machine supplies — 22mm service valve on the washing machine hot and cold feeds
• Water Regulations Schedule 2 Para 15 — a servicing valve or other convenient means of isolation is required on every water fitting supplied with water, making service valves a code-mandated item on every new or replacement appliance connection

Chrome-plated finish suits exposed pipework in kitchens and bathrooms. The 15mm size covers the vast majority of domestic appliance connections.

When to Use Which Valve

BS 5154 and WRAS Compliance

For any valve connected to the public water supply or used in an unvented hot water system, WRAS (Water Regulations Advisory Scheme) approval is required under the Water Supply (Water Fittings) Regulations 1999. Embrass Peerless gate valves carry BS 5154 certification and WRAS listing — always check approval marks before installing on potable water circuits. Non-approved valves can result in a water company inspection notice.

Related Products

• Flexible Tap Connectors and Isolating Valves — braided hose sizing and service valve selection
• Pegasus Pressfit Copper Pipe Fittings — 15mm, 22mm and 28mm press-fit couplers and tees
• 32mm and 40mm Push-Fit Waste Pipe Fittings — branch, bend, and reducer selection

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