Mikrofill 3 Pressurisation Unit - EFD120021

Name: Mikrofill 3 Pressurisation Unit - EFD120021
Brand: Mikrofill
SKU: EFD120021
Price: 1498.8 GBP
Availability: InStock

In stock

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Established 1975
Trusted by thousands of customers

Use discount code MIK65 for £65 off at checkout

The Mikrofill 3 is the most advanced ‘direct type’ pressurisation unit available, suitable for sealed LPHW / CHW (heating and chilled water) systems of any size. Unlike ‘pump type’ units, it connects directly to the building’s incoming mains or boosted supply and fills the system without a pump — using the energy already in the supply, with no RPZ valve required.

It is the most energy-efficient unit of its kind, drawing as little as 10W on standby and 30W fully operational. Wall-mounted and compact at just 270 × 250mm, with integral Fluid Category 4 backflow prevention and a large colour display. Pre-commissioned packages with appropriately sized vessels are available.

Cat 4

Backflow protection

10W

Standby use

Pumpless

Direct to mains

270mm

Compact, wall-mounted

Connects directly to mains / boosted supply — pumpless, using energy already in the supply; no RPZ valve required
Integral Fluid Category 4 backflow prevention — fills any LPHW/CHW system from empty
Exceptionally energy efficient — 10W standby / 30W operational; up to 97% more efficient than some pump-type units
Comprehensive electronic manager — large colour display, fill volume indicator, two methods of flood protection
Compact, wall-mounted — only 270 × 250mm; fits the smallest of plant rooms
Pre-commissioned packages available — supplied with appropriately sized vessels and service drain valves; no onsite commissioning required

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Full Description

More about this product

Full Description

Use discount code MIK65 for £65 off at checkout

Product overview

The Mikrofill 3 is the most advanced ‘direct type’ pressurisation unit available, suitable for sealed system LPHW / CHW (heating and chilled water) applications of any size. Unlike ‘pump type’ pressurisation units, it is designed to connect directly to a building’s incoming mains or boosted water supply and fill a heating or chilled water system without the use of a pump.

The Mikrofill 3 utilises the energy already generated by the mains or boosted water supply and does not contain an RPZ valve. It is the most energy-efficient unit of its kind, consuming as little as 10 watts on standby and 30 watts fully operational per hour — up to 97% more efficient than some pump-type units.

Wall-mounted and compact at just 270 × 250mm, with integral Fluid Category 4 backflow prevention, a comprehensive electronic pressurisation manager, and a large colour display. Pre-commissioned packages are available which include the Mikrofill 3 with appropriately sized vessels and service drain valves.

Cat 4

Backflow protection

10^W

Standby use

30^W

Operational

270^mm

Wall-mounted H

Pumpless — connects directly to the mains

Why ‘direct type’ rather than a pump?

A conventional pressurisation unit uses a pump to push water into a sealed heating or chilled system. The Mikrofill 3 instead harnesses the pressure already present in the building’s mains or boosted supply — so there is no pump to power, service, or replace.

That makes it dramatically more efficient (10–30W versus the much higher draw of pump-type units), quieter, and simpler. Integral Fluid Category 4 backflow prevention is built in, so no separate RPZ valve is required.

Features

Integral Fluid Category 4 backflow prevention

Built-in Cat 4 protection means no separate RPZ valve is required — saving cost, space, and annual RPZ servicing.

Fills any LPHW/CHW system from empty

Suitable for sealed heating and chilled water systems of any size, filling from empty and maintaining set pressure automatically.

Comprehensive electronic manager

Intelligent pressurisation manager with a large colour screen display and fill volume indicator for clear monitoring.

10W standby / 30W operational

The most energy-efficient unit of its kind — up to 97% more efficient than some pump-type pressurisation units.

Compact wall-mounted unit

Just 270 × 250mm — compact enough to fit in the smallest of plant rooms.

Two methods of flood protection

Dual flood-protection safeguards guard against overfilling and system faults for added peace of mind.

Pre-commissioned packages available

Supplied with appropriately sized expansion vessels and service drain valves — no onsite commissioning required.

Aids water treatment calculation

The fill volume indicator helps accurately calculate inhibitor and water treatment dosing for the filled system.

Clear, concise instruction

Straightforward setup and operation, with clear on-screen guidance throughout fill and pressurisation.

Benefits at a glance

Connects directly to the supply

No pump to power, service, or fail — uses the energy already in the mains or boosted supply.

97% more energy efficient

10–30W operation versus the far higher running cost of some pump-type units.

No RPZ valve needed

Integral Cat 4 backflow prevention removes the cost and annual servicing of a separate RPZ valve.

Fits the smallest plant rooms

Compact 270 × 250mm wall-mounted footprint suits tight and awkward plant spaces.

No onsite commissioning

Pre-commissioned packages arrive ready to install, with vessels and service drain valves matched to the system.

Aids water treatment calculation

Accurate fill volume data supports correct inhibitor dosing and system water treatment.

How it compares

Three popular sealed-system pressurisation units side by side. The Mikrofill 3 and the Flamco Flexfiller Direct G4 are both direct type (pumpless) — they use the energy already in the mains supply and need no RPZ valve. The Flamco Minipress 130 is a more affordable pump type unit with an internal break tank, better suited to smaller systems.

Mikrofill

Mikrofill 3 this product

Direct type — pumpless

14 l/min fill @ 2 bar

Max cold fill 4.7 bar

No RPZ valve required

Integral Cat 4 backflow

10W standby / 30W operational

BMS volt-free relays

Vessels 8–1000L

2-year warranty

Flamco

Flexfiller Direct G4

Direct type — pumpless

Up to 14 l/min fill

Pressure set in 0.1 bar steps

No RPZ valve required

Leak & flood protection

Self-learning controller

MODBUS RTU + BACnet

Systems up to 50,000L

£898 + VAT

Flamco

Flexfiller Minipress 130

Pump type — internal break tank

0.5 l/min topup @ 1 bar

Topup pressure to 3.0 bar

Cat 5 (AB weir overflow)

Leak & flood protection

2L internal break tank

MODBUS RTU

Heating vessels to 300L

£427 + VAT

Feature	Mikrofill 3 this	Flamco Direct G4	Flamco Minipress 130
Type	Direct (pumpless)	Direct (pumpless)	Pump type
Fill flow rate	14 l/min @ 2 bar	Up to 14 l/min	0.5 l/min @ 1 bar
RPZ valve required	No — integral Cat 4	No	No — Cat 5 air gap
Power consumption	10W / 30W	Low (pumpless)	Higher (pump)
BMS connectivity	Volt-free relays	MODBUS + BACnet	MODBUS RTU
Suited to system size	Any size (vessels 8–1000L)	Up to 50,000L	Heating vessel to 300L
Mounting	Wall — 270 × 250mm	Wall	Wall
WRAS approved	Yes (1212069)	Yes	Yes
Price (ex VAT)	Use code MIK65	£898.00	£427.00

Which should I choose?
Mikrofill 3 — the efficient direct-type choice for sealed LPHW/CHW systems of any size, with integral Cat 4 backflow and no RPZ valve to maintain.
Flamco Direct G4 — also pumpless, with MODBUS + BACnet and capacity for very large systems up to 50,000L, at a higher price point.
Flamco Minipress 130 — the budget pump-type option for smaller systems where topup flow and system volume are modest. Contact us if you’d like help choosing.

Technical specifications

Model / SKU	Mikrofill 3 Pressurisation Unit / EFD120021
Type	Direct type (pumpless) sealed-system pressurisation unit
Application	Sealed LPHW / CHW systems of any size
Water supply	Direct from mains or boosted supply
Backflow protection	Integral Fluid Category 4 — no RPZ valve required
Power consumption	10W standby / 30W operational (per hour)
Power supply	230V, 50Hz, 1 phase — 3A fused
System outlet connection	15mm isolation valve (15mm copper or approved plastic)
Drain	¾″ BSP tundish (to suitable drain)
BMS connectivity	Volt-free relays — low / high pressure and common fault / boiler interlock
Display	Large colour screen with fill volume indicator
Mounting	Wall-mounted — 270mm high × 250mm wide
Compatible vessels	Mikropro expansion vessels 8L – 1000L (larger by request)

iA suitably sized expansion vessel and a system pressure relief / safety valve must be fitted on all sealed systems. The expansion vessel charge must match the cold fill pressure. Contact us for help sizing vessels for your system.

Frequently asked questions

Is there a discount available?

Yes — use discount code MIK65 for £65 off at checkout. In stock and ready to dispatch.

What is a ‘direct type’ pressurisation unit?

A direct type unit connects straight to the mains or boosted water supply and uses the pressure already in that supply to fill and pressurise a sealed heating or chilled water system — with no internal pump. This makes it far more energy-efficient, quieter, and simpler to maintain than conventional pump-type units.

Do I need a separate RPZ valve?

No — the Mikrofill 3 has integral Fluid Category 4 backflow prevention built in, so no separate RPZ valve is required. This saves the purchase cost, the plant-room space, and the annual RPZ servicing that pump-type units often need.

Does it include an expansion vessel?

This listing is for the Mikrofill 3 unit itself. A suitably sized expansion vessel must be fitted to the system — Mikropro vessels are available from 8L to 1000L (larger by request). We also offer pre-commissioned packages that include the unit, an appropriately sized vessel, and service drain valves. Contact us for help sizing.

What connections and supply does it need?

The unit connects to the system via a 15mm isolation valve (15mm copper or approved plastic pipework), with a ¾″ BSP tundish to a suitable drain. It requires a permanent 230V 50Hz single-phase 3A fused supply. Volt-free BMS relays are included for low/high pressure indication and boiler/chiller interlock.

Where can I install it?

The Mikrofill 3 is a wall-mounted unit measuring just 270 × 250mm — compact enough to fit in the smallest of plant rooms. It should be sited indoors with access to the system pipework, a drain for the tundish, and a fused electrical supply.

Downloads

manual PDF
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Brochure PDF
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Delivery Information

Standard delivery:
Standard delivery is free on most orders. Some items may incur a delivery charge depending on weight, size or value. Any applicable charge will be displayed at checkout.

Deliveries will typically be made between 7am and 6pm, Monday to Friday (excluding public holidays).

Next day delivery:
Next working day delivery is available for a £16.50 + VAT delivery charge.

Orders must be placed before 12 noon to qualify for next working day delivery. Orders placed after 12 noon on Thursday but before noon on Friday will be delivered the following Monday. Orders placed after 12 noon on Friday will be delivered on Tuesday.

Pallet/Large/Difficult items:
Some large, heavy or difficult to transport items may incur an additional delivery charge. Please contact us for a delivery quote before ordering.

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Frequently Asked Questions

Quick answers to common questions about the Mikrofill 3 Pressurisation Unit – EFD120021. For technical specifications, see the product details above; for sizing or installation advice, contact our team. If you have any other questions, we're happy to help.

What is a mains pressure boosting system?

A mains pressure boosting system increases the pressure and flow of water from the incoming mains supply into a property. It typically combines a pump and a storage or expansion tank, drawing water from the mains and delivering it to taps, showers and appliances at a stronger, more consistent pressure. They are used where the incoming mains is too weak to serve modern outlets reliably.

When do I need a mains booster pump?

You normally need a mains booster if static mains pressure is below 1.5 to 2 bar, if showers run weakly when other taps are open, or if combi boilers struggle to deliver hot water. Anglian Pumping recommends checking static pressure at the stop tap before specifying a system, then choosing a model rated for the number of bathrooms and outlets in the property.

What size mains booster do I need for my home?

Sizing depends on the number of bathrooms, the type of fittings and the static mains pressure. As a guide, a 1 to 2 bathroom property with combi boiler or single shower often needs 1.6 to 3 bar boost. A 2 to 3 bathroom property typically needs 3 to 4.5 bar with an integral break tank. Larger homes need a tank-and-pump system such as the DAB Esybox with Esytank or a Powertank set.

What is a water booster pump?

A water booster pump increases the pressure of an existing water supply to give stronger flow at taps, showers and appliances. It can be a small inline pump fitted to the incoming mains, or a larger pump and tank set that draws from a break tank to feed the whole house. Boosters do not create water – they raise the pressure of the water already coming in.

What is the difference between an inline booster and a tank-and-pump booster?

An inline booster connects straight onto the incoming mains and is limited to 12 litres per minute under UK water regulations – examples include the Salamander HomeBoost and WaterBoost WB-Compact. A tank-and-pump booster, such as the Grundfos Home Booster or DAB Esybox with Esytank, draws from a break tank and can deliver much higher flow rates for larger homes with multiple bathrooms.

What is a variable speed booster pump?

A variable speed booster uses an inverter to adjust pump speed in real time to match demand. It maintains constant pressure as outlets open and close, runs more quietly than a fixed-speed pump and typically saves up to 50 per cent of the energy a fixed-speed equivalent would use. The DAB Esybox, DAB Esybox Mini 3 and Grundfos Scala2 are common variable speed examples.

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