JG Speedfit Push-Fit Plumbing: The Complete Guide for Plumbers

JG Speedfit is the UK's leading push-fit plumbing system — used by plumbers on everything from bathroom tap connections to full central heating installs. The system is fast, reliable, and reusable, and once you understand how it works and where it's appropriate, it covers the majority of domestic plumbing situations. This guide covers the full Speedfit range, how to install it correctly, and where not to use it.

How JG Speedfit Works

Speedfit push-fit fittings use a collet-and-O-ring mechanism. When you push a pipe into a Speedfit fitting, a set of stainless steel grab teeth in the collet grip the pipe and an EPDM O-ring creates a watertight seal. The pipe is held under pressure — the harder the push, the tighter the grip.

To release a fitting, you push the collet ring toward the body of the fitting while pulling the pipe — this releases the grab teeth and allows the pipe to slide out. You can disconnect and reconnect Speedfit fittings multiple times without any degradation to the fitting.

This is the key advantage over compression and solder: no tools required for the connection itself. A push-fit connection takes seconds and is reversible.

Push-Fit vs Compression vs Solder: Which to Use

The practical rule: Speedfit works for cold water, central heating, and domestic hot water circuits in accessible locations. Don't use it buried in screed or within the thermal distance of a boiler heat source. For everything else, push-fit is the right call.

The Core Fitting Types

Straight Couplers

The most-used fitting — for joining two lengths of pipe in a straight run, or extending an existing run. Available in equal and reducing versions.

• JG Speedfit 15mm Straight Coupler — £2.40
• JG Speedfit 22mm Straight Connector — £3.40
• JG Speedfit Reducing Coupler 15mm x 10mm — £4.99 — for reducing to a 10mm branch (underfloor heating manifold feeds, some appliance connections)

Elbows

For changing direction — around corners, over obstacles, at fixture connection points. The 15mm elbow is one of the highest-turnover fittings in a plumber's van.

• JG Speedfit 15mm Equal Elbow — £2.69
• JG Speedfit 22mm Equal Elbow — £4.16
• JG Speedfit 22mm x 15mm Reducing Elbow — £5.69 — for stepping down at the branch point of a circuit

Tees

For branching a circuit — adding a spur to an existing run, or splitting flow and return circuits.

• JG Speedfit 15mm Equal Tee — £3.78
• JG Speedfit 22mm Equal Tee — £5.49

Service Valves and Stop Valves

Speedfit valves allow full push-fit valve installation — no need to transition to compression for isolation points. Fit isolating valves on every appliance connection as standard.

• JG Speedfit 15mm Service Valve — £7.99 — quarter-turn isolation, inline, both push-fit ends
• JG Speedfit 15mm Stop Valve — £13.99 — traditional gland-packing stop valve in push-fit body
• JG Speedfit 22mm Service Valve — £12.99 — for main circuit isolation on 22mm runs
• JG Speedfit Double Check Valve 15mm — £12.99 — WRAS approved, required on cold water connections to appliances such as washing machines and dishwashers under Water Supply (Water Fittings) Regulations

15mm vs 22mm: Which Circuit Gets Which Size

The pipe size rule in domestic plumbing:

• 15mm: Individual appliance feeds — taps, valves, radiator connections, bathroom fixtures. Most domestic branches.
• 22mm: Main circuit runs — flow and return from the boiler, main cold water supply, kitchen sink cold run, shower supply. Any run serving multiple 15mm branches.
• 28mm: High-output boilers, large central heating systems, commercial. Usually compression at this size.

The practical test: if you're feeding a single appliance or radiator, it's 15mm. If you're laying the spine of a circuit that feeds multiple appliances, it's 22mm.

Installation: Getting It Right Every Time

Push-fit failures are almost always installation errors. The fitting is reliable — the failure is in preparation.

1. Cut square: Use a pipe cutter or hacksaw with a guide, not a junior hacksaw freehand. A pipe cut at an angle won't seat properly in the O-ring and will leak under pressure.
2. Deburr: Use a deburring tool or the back of the pipe cutter to remove the internal and external burr. Burrs damage the O-ring on insertion.
3. Use a pipe insert: For plastic (barrier pipe) or soft copper, always fit a Speedfit pipe insert (stiffener) before pushing into the fitting. Without it, the pipe collapses under the collet teeth over time. For hard copper this step is optional but good practice.
4. Mark the depth: Speedfit fittings have a published insertion depth. Mark the pipe with a pencil or use the Speedfit depth gauge tool before inserting. Check the mark is at the fitting body after connection — if the mark hasn't reached the body, the pipe isn't fully seated.
5. Push firmly: Push the pipe straight in until it stops. You'll feel a slight resistance as the teeth engage, then a positive stop. Don't twist — push straight.
6. Test before closing the wall: Always pressurise and check before covering connections. A Speedfit fitting that's not fully seated will weep under pressure — it will not hold short-term and then fail later.

JG Speedfit In Stock at APM

We stock the full JG Speedfit range in 15mm and 22mm — couplers, elbows, tees, reducers, valves, and accessories — for same-day collection from our trade counter in Acton or next-day delivery.

If you're setting up a van stock, a practical Speedfit starter kit covers:

• 5x 15mm straight coupler
• 5x 15mm equal elbow
• 3x 15mm equal tee
• 2x 22mm straight connector
• 2x 22mm equal tee
• 4x 15mm service valve
• 2x 22mm service valve
• A tube of pipe inserts (Speedfit TSM15 or equivalent)

APM Plumbing & Electrical | 24 Western Avenue, Acton, London W3 7TZ | 020 8702 8080 | apmi.uk