Mikrofill Pressurisation Unit’s
Mikrofill 3 Pro Pressurisation unit 72846
- Established 1975
- Trusted by thousands of customers
The Mikrofill 3 PRO is a fully automatic sealed-system filling device for the water management of domestic and commercial heating and cooling systems. Compact, efficient and easy to install and commission, it uses smart logic alongside pressure and flow sensors to detect and alert on system issues early, while requiring minimal maintenance.
WRAS-approved with integral Fluid Category 4 backflow prevention (approval no. 2307805), it delivers up to 8.7 bar cold fill pressure, a full-colour 3.95″ display, leak detection, volume logging and MODBUS RTU with four customisable BMS outputs. Wall-mountable and compact at just 250mm wide. Standard 2-year warranty, extended to 4 years when purchased with a vessel package.
- WRAS-approved — Fluid Category 4 backflow prevention (approval no. 2307805); suitable for sealed heating and chilled water systems
- Smart fault logic & leak detection — early detection and alerts for system issues, with minimal maintenance
- Full-colour 3.95″ LCD — comprehensive electronic pressure management and on-screen service reminders
- Accurate flow monitoring & volume logging — live flow readings to ±3%; logs up to 100 time/date-stamped changes and faults
- MODBUS RTU + 4 customisable BMS outputs — full building management integration
- Standard 2-year warranty — extended to 4 years when purchased with a vessel package
More about this product
The Mikrofill 3 PRO is a fully automatic sealed-system filling device for the water management of domestic and commercial heating and cooling systems. The unit is compact, efficient, and easy to install and commission. Using smart logic alongside pressure and flow sensors, it provides early detection and alerts for system issues, and is designed to require minimal maintenance.
WRAS-approved with integral Fluid Category 4 backflow prevention (approval no. 2307805), it offers up to 8.7 bar cold fill pressure, a full-colour 3.95″ display, leak detection, comprehensive volume logging, and MODBUS RTU with four customisable BMS outputs for full building management integration.
Key features
- WRAS-approved — Fluid Risk Category 4 backflow prevention (WRAS approval no. 2307805)
- 8.7 bar max cold fill pressure — suitable for systems of significant height
- Compact, wall-mountable design — just 250mm wide; backplate supplied
- Full-colour 3.95″ LCD display with comprehensive electronic pressure management
- Accurate flow rate monitoring & volume logging — live readings to ±3%
- Leak detection & smart fault logic for rapid fault diagnosis
- MODBUS RTU + 4 customisable BMS outputs
- Large memory capacity — records up to 100 parameter changes and fault conditions combined, all time and date stamped
- Easy to install and set up
- Standard 2-year warranty — extended 4-year warranty when purchased with a vessel package
Smart control & monitoring
- Colour backlit LCD screen with pressure setting resolution of ±0.1 bar
- Low inlet pressure cut-out (0.3 bar) and high/low pressure fault indication
- User password access and hand mode for manual operation
- Flood protection (run-time limiter) and user-set on-screen service reminder
- Customisable volt-free contacts and usage monitor with fill volume, logs and counters
- Live, in-situ testing for service and repair
Applications
- Maintaining system pressure in large domestic and commercial sealed heating systems
- Maintaining system pressure in chilled water systems, refrigeration units and industrial cooling systems
Operating specifications
| Max inlet pressure | 9 bar |
| Max cold fill pressure | 8.7 bar |
| Max operating pressure | 9 bar |
| Max flow rate | 12 l/min |
Dimensions & connections
| Height (to bottom of connections, without hoses) | 290 mm |
| Height (to bottom of tundish) | 386 mm |
| Width | 250 mm |
| Depth | 155 mm |
| Weight (without hoses) | 5.3 kg |
| Inlet / System connection | 15 mm compression |
| Drain connection | 22 mm compression |
| Wall attachment | Backplate supplied (fixings not included) |
| Clearances (L / R / top / front) | 100 / 170 / 100 / 750 mm |
Electrical & environmental
| Supply voltage | 230 V / 1 ph / 50 Hz |
| Fuse rating | 3 A |
| BMS relays (max load) | 5 A |
| Ambient temperature range | 5 – 45°C |
| Inlet water temperature range | 5 – 23°C |
| System water temperature range | 5 – 85°C |
| Maximum relative humidity | 70% (non-condensing) |
| IP rating | IP55 |
| Fluid protection | WRAS Category 4 / Kiwa Regulation 4 |
Warranty & accessories
- Standard warranty: 2 years
- With vessel package: 4 years
- Supplied with: 2× braided hoses with integrated isolation valve
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Data Sheet PDFDownload
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 Pro Pressurisation unit 72846. 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 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.