The JG Speedfit 312 Compact Pressure Reducing Valve (22mm push-fit, code PRED312110) brings incoming mains water pressure down to a safe, steady level, protecting taps, showers, dishwashers, boilers, and heat pump installations from damage caused by excess pressure. Manufactured by Reliance Valves (RWC) and built around JG Speedfit's tool-free push-fit connection system, it is designed to go in fast — no soldering, no threading, no compression fittings — which makes it especially practical in the confined spaces typical of UK plant cupboards and under-sink installations.
22mm
Push-Fit Connection
1.5–5.5 bar
Adjustable Outlet
16 bar
Max Inlet Pressure
10:1
Pressure Reduction Ratio
25°C
Max Working Temp
5 Year
Manufacturer Guarantee
Please Note
This push-fit version is rated for cold water use up to 25°C only. The same 312 Compact PRV body is also available in FBSP, MBSP union, and compression connections (sold separately), which carry higher temperature ratings of up to 70°C for hot water applications. If the installation needs hot water pressure reduction, a threaded or compression-ended variant is the correct choice rather than this push-fit model.
Single-Piece Replaceable Cartridge
All the working parts of the valve — the pressure-setting mechanism, seat, and seals — sit inside one removable cartridge. If the valve ever needs servicing, the whole cartridge swaps out in minutes without disturbing the pipework around it, which keeps maintenance costs and downtime to a minimum.
Drop-Tight Under Flow and No-Flow
The valve holds its set outlet pressure accurately whether water is flowing or static, so downstream pressure doesn't creep up when taps are closed. This is the behaviour that actually protects appliances long-term, rather than just at the moment of installation.
Tool-Free Push-Fit Installation
JG Speedfit push-fit ends mean the valve can be fitted and removed without tools — push the pipe fully home to connect, or push the collet back to release it. This cuts installation and servicing time significantly compared with soldered or threaded alternatives.
Integral Strainer Protection
A stainless steel strainer is built into the valve body ahead of the seat, filtering out debris and scale particles that would otherwise wear the seat or cause the valve to stick over time.
Install in Any Orientation
Gauge ports are positioned on both sides of the valve base, so it can be fitted horizontally, vertically, or at any angle the pipework demands, with pressure test ports accessible either way.
Corrosion-Resistant DZR Brass Construction
The body and internal components are machined from DZR (dezincification-resistant) brass, paired with EPDM seals and a zinc-plated spring, giving the valve long service life even in the harder water conditions common across much of the UK.
General
Brand
JG Speedfit (Reliance Valves / RWC)
Product Code
PRED312110
Product Range
312 Compact Pressure Reducing Valve
Connection Size
22mm push-fit
Application
Domestic hot & cold water systems (cold water rated on this push-fit variant)
Performance
Maximum Working (Inlet) Pressure
16.0 bar
Adjustable Outlet Pressure
1.5 – 5.5 bar
Pressure Reduction Ratio
10:1
Maximum Working Temperature
25°C (cold water, push-fit connection)
Valve Action
Drop-tight; maintains set pressure under flow and no-flow conditions
Construction
Body
DZR brass
Internal Components
DZR brass
Seals
EPDM
Spring
Zinc-plated spring steel
Strainer
Stainless steel
Diaphragm
EPDM
Cover
Glass-filled nylon polymer
Dimensions (Push-Fit, mm)
Connection Size (A)
22
Body Width (B)
32.8
Body Depth (C)
63.5
Overall Length (D)
110
Overall Height (E)
94
Servicing & Compliance
Cartridge
Single-piece, replaceable
Guarantee
5 years
Approvals
WRAS approved for potable water use
PEX Pipe Note
A JG Speedfit Superseal Insert must be used with PEX pipe to maintain pipe roundness and joint strength
Data Note
An EAN/barcode for the PRED312110 could not be confirmed from manufacturer or distributor sources at the time of writing, so it has been omitted from this listing rather than estimated.
What does a pressure reducing valve actually do?
It takes the incoming mains water pressure — which can vary considerably and sometimes run well above what plumbing fittings are designed for — and brings it down to a steady, adjustable level. This protects taps, valves, appliances, and heating system components from the wear, leaks, and bursts that excess pressure can cause over time.
Can this valve be used on hot water?
No. The push-fit version (PRED312110) is rated for cold water use up to 25°C only. The same 312 Compact PRV is available with FBSP, MBSP union, or compression connections, which are rated for hot water up to 70°C — choose one of those variants for hot water applications.
Do I need any tools to install it?
No tools are required for the push-fit connections themselves — simply push the pipe fully into the valve to make a secure, leak-free joint. A spanner may still be useful for supporting fittings elsewhere in the installation, and standard good practice (isolating the supply, checking for leaks) still applies.
How do I set the outlet pressure?
The valve has gauge/test ports on either side of its base. With a pressure gauge connected downstream, the outlet pressure can be adjusted and verified within the valve's 1.5–5.5 bar range.
What happens if the strainer or cartridge gets blocked?
Because all the working parts are housed in a single-piece replaceable cartridge, servicing is straightforward — the cartridge (including the integral strainer) can be removed and replaced without needing to cut into the surrounding pipework.
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
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