Name: WaterBoost Mikrofill 3 Pro + HWB-24LX Pressurisation Kit
Brand: WaterBoost
SKU: WBPK3P24
Price: 1668 GBP
Availability: InStock

WaterBoost Mikrofill 3 Pro + HWB-24LX Pressurisation Kit

Any questions? Message us on WhatsApp

Established 1975
Trusted by thousands of customers

Mikrofill 3 PRO pressurisation unit + GWS HeatWave HWB-24LX expansion vessel + ¾” service valve, for heat pump systems up to 770 litres.

A complete set for keeping a sealed heating system at pressure. The Mikrofill 3 PRO is a pumpless, direct-type unit. It connects straight to the mains, fills the system from empty and tops it up automatically, with WRAS-approved Category 4 backflow protection built in. The HeatWave HWB-24LX absorbs the expansion as the water heats, and the lockable service valve lets the vessel be isolated and drained for checks.

770 L

System size up to

8.7 bar

Max cold fill pressure

24 L

Expansion vessel

Pressurisation unit

Mikrofill 3 PRO (72846) — made in Britain by Mikrofill

Expansion vessel

HeatWave HWB-24LX — by Global Water Solutions (GWS)

Wall-mounted unit, colour display, leak detection, MODBUS RTU and 4 BMS outputs. Inline vessel, 6 bar rated. For closed-loop heating and chilled water systems. 2-year warranty on the Mikrofill unit.

Full Description

More about this product

Full Description

What’s in the kit

The WaterBoost Mikrofill 3 Pro + HWB-24LX Pressurisation Kit brings together three components, matched to heat pump systems up to 770 litres:

Mikrofill · made in Britain

Mikrofill 3 PRO pressurisation unit (72846)

Pumpless, direct-type unit with a 3.95″ colour display. Fills and tops up the system straight from the mains, up to 8.7 bar. Supplied with two braided hoses with integrated isolation valves, and a wall backplate.

Global Water Solutions (GWS)

HeatWave HWB-24LX expansion vessel

24 litre inline heating expansion vessel with a high-grade butyl diaphragm. ¾” BSPT connection, 6 bar, factory pre-charged to 0.7 bar.

Included

¾” lockable service valve

Fits the vessel connection. Isolates and drains the vessel so the pre-charge can be checked, and locks open in normal use.

Why the Mikrofill 3 PRO

No pump, no break tank

It uses the pressure already in the mains or boosted supply, so there’s no pump to wear out and nothing to hear.

WRAS Category 4

Fluid Risk Category 4 backflow prevention built in, WRAS approval 2307805 and Kiwa Regulation 4. No separate RPZ valve needed.

Fills from empty

Up to 12 l/min, with live flow readings to ±3% and a logged fill volume, so you know exactly how much water went in for inhibitor dosing.

Leak detection and smart fault logic

Spots leaks and system faults early, with flood protection by run-time limiter and high/low pressure alarms.

BMS ready

MODBUS RTU and 4 customisable volt-free outputs. Logs up to 100 time-stamped parameter changes and faults.

Compact and sealed

250 × 155 × 290 mm, IP55, wall-mounted on the supplied backplate.

How it’s installed

The vessel connects to the heating return through the service valve, which is locked open in use. The unit’s system hose connects into the return near the vessel, and its inlet hose takes the mains or boosted cold supply. Mikrofill’s schematic shows a pressure reducing valve on the incoming supply.

The unit’s 22 mm tundish drain goes to a visible discharge point. The safety valve stays on the heat source. Power is 230 V from a 3 A fused spur. Leave 100 mm clear to the left and top, 170 mm to the right, and 750 mm in front.

Specifications

Kit
Application	Sealed heating and chilled water systems (closed loop)
System volume — heat pump	Up to 770 L (60 °C flow)
System volume — boiler	Up to 430 L (82 °C flow)
Sizing basis	3 bar safety valve, 0.7 bar vessel pre-charge
Max working pressure	6 bar (set by the vessel)
Max system water temperature	85 °C (set by the unit)
Service valve	¾”, lockable, with drain
Mikrofill 3 PRO (72846)
Type	Pumpless, direct type
Max inlet pressure	9 bar
Max cold fill pressure	8.7 bar
Max operating pressure	9 bar
Max flow rate	12 l/min
Low inlet pressure cut-out	0.3 bar
Backflow protection	WRAS Category 4 (2307805), Kiwa Regulation 4
Display	3.95″ backlit colour LCD
Pressure setting resolution	±0.1 bar
Communication	MODBUS RTU, 4 BMS outputs (5 A max)
Connections	Inlet 15 mm compression; system 15 mm compression; drain 22 mm compression
Supplied with	2 × braided hoses with integrated isolation valves; backplate (fixings not included)
Electrical	230 V / 1 ph / 50 Hz, 3 A fuse
IP rating	IP55
Ambient / inlet / system water temperature	5–45 °C / 5–23 °C / 5–85 °C
Max relative humidity	70% non-condensing
Dimensions (W × D × H)	250 × 155 × 290 mm (386 mm to bottom of tundish)
Weight	5.3 kg (without hoses)
Warranty	2 years
GWS HeatWave HWB-24LX
Nominal volume	24 L
Type	Inline, supported on system pipework
Connection	¾” BSPT
Max operating pressure	6 bar
Operating temperature	−10 to 99 °C
Factory pre-charge	0.7 bar
Diaphragm	High-grade butyl
Dimensions (H × Ø)	442 × 290 mm
Weight	4.4 kg

FAQs

How do I know 770 litres covers my system?

Add up the water in the heat source, buffer tank, cylinder coil, emitters and pipework. The 770 L figure is based on 60 °C flow, a 3 bar safety valve and the vessel’s 0.7 bar pre-charge. For a bigger system, see the Mikrofill 3 Pro + HWB-35LX kit or larger.

Can I use it on a boiler system?

Yes, up to 430 L at 82 °C flow. A boiler runs hotter, so the water expands more and the same vessel covers less.

What fill pressure can it reach?

Up to 8.7 bar, but never more than your incoming supply. The 3 PRO has no pump, so it uses the pressure already in the mains or boosted supply, and it cuts out if the inlet drops below 0.3 bar. In practice the fill pressure is set well below the heat source’s safety valve.

What’s the service valve for?

It isolates the vessel from the system and drains its water side, so the pre-charge can be checked or the vessel swapped without draining the system. It must be locked open in normal use.

Can I use glycol?

Yes, propylene glycol up to a 50% mix. Don’t use ethylene glycol.

Can this go on a hot water cylinder or a potable system?

No. HeatWave vessels are for closed-loop systems only. For potable hot water, use a GWS ThermoWave vessel.

Downloads

Mikrofill 3 Pro PDF
Download
Data Sheet PDF
Download

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.