Free UK delivery over £50

30 Day Money Back Guarantee

Expert Support 7 Days a Week

Subscribe & Save

Honeywell Pressure Reducing Valve - 1/2" F x 3/4" M (Dual Thread)

SKU: D04FM
In stock

Price:
Sale price£39.99
Price:
Sale price£39.99
Free express delivery for all orders over £50

Free express delivery for all orders over £50

Calculating...
FREE Express Delivery: Orders over £50 to UK mainland
Next Day Delivery: £5.99 (order before 3pm)
Standard Delivery: £2.99 for 2-3 working days
Guaranteed to Fit

Guaranteed to Fit

Perfect fit guaranteed on all recommended products – or you’ll get a full refund.

Unsure if it’s the right fit? Ring us on 0161 768 9566 or email us.

Description

The Honeywell D04FM is a high-quality pressure reducing valve (PRV) designed to protect your plumbing system from excessive mains water pressure. By reducing and maintaining a constant outlet pressure, it prevents pressure-related damage to pipes, fittings and appliances while also reducing water consumption and minimising flow noise throughout your installation.

This valve is particularly recommended for use alongside whole house water filtration systems, where consistent, regulated water pressure is essential for optimal filter performance and longevity. Excessive or fluctuating mains pressure can reduce filter cartridge lifespan and put unnecessary strain on filtration housings and fittings — installing a PRV before your filtration system helps prevent these issues and ensures your system operates as intended.

Built with a dezincification-resistant brass body and fibre-reinforced EPDM diaphragm, the D04FM is engineered for long-term reliability in potable water systems. The outlet pressure is easily adjustable between 1.5 and 6 bar using the green adjustment knob — no special tools required.

A key advantage of the D04FM is its inlet pressure balancing design. Fluctuations in mains supply pressure won't affect your set outlet pressure, giving you consistent, stable water pressure throughout your property.

Suitable for both horizontal and vertical installation (spring bonnet facing upwards when vertical). Handles inlet pressures up to 16 bar and operating temperatures up to 40°C per DIN EN 1567, or up to 70°C at a maximum operating pressure of 10 bar.

Key Features:

  • ½" BSP male inlet x ¾" BSP male outlet (external thread on both sides)
  • Ideal companion for whole house water filtration systems
  • Outlet pressure adjustable from 1.5 to 6 bar
  • Maximum inlet pressure: 16 bar
  • Inlet pressure balancing — stable outlet pressure regardless of supply fluctuations
  • Dezincification-resistant brass housing
  • WRAS approved and meets KTW/W270 and ACS potable water guidelines
  • G¼" pressure gauge port (gauge sold separately)
  • Compact design — just 84mm long
  • Suitable for horizontal and vertical installation

Technical Specifications:

  • Connection: ½" BSP male inlet, ¾" BSP male outlet
  • Nominal size: DN15
  • Inlet pressure: max. 16 bar
  • Outlet pressure: 1.5–6 bar (adjustable)
  • Minimum pressure drop: 1 bar
  • Max operating temp: 40°C (70°C at max 10 bar)
  • Dimensions: L 84mm x H 106mm
  • Weight: 0.32 kg
  • Medium: Potable water

Data Sheet Download

Shipping

  • Orders ship within 1 business day (Mon–Fri, excl. holidays).
  • You’ll get an email as soon as your order is on its way.

Delivery Options

  • FREE Express Delivery on UK orders over £50
  • Next Day Delivery – £5.99 (order before 3pm)
  • Standard Delivery – just £2.99

Click here for international details.

Filter Flair
OEM Brands
Other Online Sellers
Perfect Filter Guarantee
✅ Always fits or your money back
✅ Fits (official product)
❌ Risk of wrong/ incompatible filter
Delivery Speed
✅ Next-day tracked delivery available
❌Often slower, limited stock
❌Unpredictable shipping times from abroad.
Customer Service
✅ UK-based, 7-Day Specialist Support
❌ Outsourced India-based centres
❌ Unskilled AI chatbot support
Price and Value
✅ Lower price, same OEM reliability
❌ Sticker price with no savings
❌ Unskilled AI chatbot support
Credibility
✅ 900+ Verified 5-star reviews
✅Big brand reputation
❌ Mixed reviews with doubts on authenticity

Fit & Compatibility

How do I know if this filter fits my fridge?
Use our “Compatibility Check” on the website. Enter your fridge’s model number and we’ll show you the exact filter you need.

Where can I find my fridge’s model number?

Most fridge model numbers are on a label inside the fridge (usually behind the crisper drawer, on the side wall, or near the door frame). See our guide here. If you can’t find it, check your user manual.

What if the filter doesn’t fit?


You’re covered by our Perfect Fit Guarantee. If it doesn’t fit, we’ll replace it or refund you, no hassle.

Can I use a non-OEM filter in my fridge?

Yes, Certified Compatible Filters are engineered to meet or exceed OEM standards, while offering the same fit and filtration performance—at a better value.

Usage & Maintenance

How often should I replace my filter?

Every 6 months, or sooner if your water has a noticeable taste or odour.

How do I install the filter?

Each filter comes with step-by-step instructions. Most simply twist or click into place—no tools required.

What happens if I forget to replace it on time?


Old filters can clog, slowing water flow and letting impurities through. Regular replacement ensures fresh, clean water and ice.

How do I know when my filter needs changing?


Look out for:

  • Water tasting or smelling off
  • Slower water flow
  • Your fridge’s “change filter” light switching on

Performance & Safety

Do these filters remove chlorine, lead, and microplastics?


Yes, our filters reduce chlorine, lead, and other common contaminants, including microplastics, so your water tastes better and is safer to drink.

Is water in the UK safe to drink without a filter?


Tap water in the UK is safe and regulated. A filter isn’t required—but it improves taste, reduces micro-contaminants, and gives extra peace of mind.

What’s the difference between OEM filters and Filter Flair alternatives?


OEM = “Original Equipment Manufacturer.” Filter Flair alternative filters deliver the same quality, compatibility, and certifications, but at a fraction of the price.

Are your filters certified (WRAS, NSF, WQA)?


Yes, all Filter Flair filters are independently tested and certified to meet WRAS, NSF, and WQA standards.

Delivery & Subscription

How quickly will my filter be delivered?


Orders are processed within 1 business day. Express UK delivery arrives in 2–3 days, and Next-Day delivery is available if you order before 3pm. For more information visit our shipping policy page

How does Subscribe & Save work?


Pick your filter, and get it delivered every six months while saving up to 10%. 

Can I pause or cancel my subscription anytime?


Yes, you’re in control, you can pause, change, or cancel anytime from your account dashboard.

How does international shipping work?


We ship worldwide. Costs and delivery times vary depending on the destination—calculated at checkout. See more information on our shipping policy page 

Trust & Assurance

Why choose Filter Flair over others?

  • Perfect Fit Guarantee
  • Genuine OEM & Certified Filters
  • Fast UK delivery
  • Subscribe & Save discounts
  • Excellent UK-based support, 7 days a week

What is the ‘Perfect Fit Guarantee’?


If your filter doesn’t fit or perform as promised, we’ll replace it or refund you in full. No risk, no hassle.

What if I need help choosing the right filter?


Use our simple Compatibility Checker or get in touch and we’ll help you find the perfect match for your fridge.

How can I get in touch with Filter Flair?


Get in touch via the ‘Contact Us’ page on our website or email our UK support team at support@filterflair.co.uk. Alternatively, give us a call on +44 (0)161 768 9566 or contact our live chat here.

You may also like

Customer Reviews

Be the first to write a review
0%
(0)
0%
(0)
0%
(0)
0%
(0)
0%
(0)

Free UK delivery over £50

Just £2.99 for anything less.

30 Day Guarantee

The filter you needor your money back.

Exceptional customer service

Specialists available to discussyour water filtration needs 7 daysa week.

Subscribe & Save

No commitment subscriptionoptions on all replacement filters.