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Mikrofill 3 Pumpless Direct-Type Pressurisation Unit LPHW & CHW Sealed Systems
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£1,770.00
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£1,475.00 Exc. VAT
£1,475.00 Exc. VAT
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✔ WRAS Approved Pumpless / Direct Type LPHW & CHW MPN: 120023
The Mikrofill 3 is the most advanced pumpless, direct-type pressurisation unit available for sealed heating and chilled water systems. Rather than using an integral pump, it connects directly to the incoming mains or boosted cold water supply and uses that pressure to fill and pressurise the system — eliminating pump maintenance, dramatically reducing energy consumption, and simplifying the installation. Suitable for LPHW and CHW systems of any size. Wall-mounted, fully electronic, and 97% more energy efficient than comparable pump-type units.
Key Features
⚡ Pumpless — no pump to maintainUses incoming mains/boosted water pressure to fill and pressurise the system directly. No motor, impeller, or pump seal to wear out or service. Consumption of just 10W on standby and 30W in operation versus 300–1000W for pump-type equivalents.
🔵 Fluid Category 4 backflow preventionWRAS approved (certificate 1806078) with Category 4 backflow protection built in — the level required for connection to heating and chilled water systems under Water Supply Regulations. No separate RPZ valve required within the unit.
📊 Full electronic pressure managementSelf-diagnostic microprocessor continuously monitors system pressure, displays status on the front panel, and triggers automatic refill sequences when pressure falls below the set cold fill threshold. Configurable parameters via on-unit Service Mode.
🔔 Three BMS volt-free relay contactsTwo independent relays provide separate low-pressure and high-pressure fault signals to a BMS. A third common relay can interlock the boiler or chiller circuit — shutting down heat/cool generation automatically on pressure alarm. All relays are independently fused at 5A.
📐 Ultra-compact wall-mounted footprintAt just 270mm (H) × 250mm (W) × 112mm (D), the Mikrofill 3 fits in the smallest plant room or service riser. Weighs significantly less than pump-type alternatives; all connections are accessible from the front for straightforward commissioning.
🇬🇧 Made in Britain — 2-year warrantyManufactured by Mikrofill Systems Ltd (Redditch, part of the Stuart Turner Group) to ISO 9001 quality standards. Supplied with a 2-year warranty. UK-based technical support.
How It Works
A conventional pump-type pressurisation unit uses an internal electric pump to draw water from a header tank or break tank and force it into the system. The Mikrofill 3 takes a different approach: it connects directly to the building's incoming mains (or boosted) cold water supply and uses a controlled electronic valve to admit water into the sealed system on demand. When the pressure transducer detects that system pressure has dropped below the set cold fill pressure, the unit opens its control valve, allows water from the mains to enter the system via the 15mm outlet connection, and closes again once the set pressure is restored.
After each fill cycle, the unit discharges a small amount of water to establish an air break — providing the Category 4 backflow prevention required by water regulations. The supplied ¾" BSP tundish handles this discharge and must be connected to a suitable drain.
📦 What's in the Box
Mikrofill 3 pressurisation unit · Inlet ballofix isolation valve with integral basket filter · 15mm outlet isolation valve · ¾" BSP tundish (discharge connection)·
Installation Summary
- Water supply: Connects to incoming mains or boosted cold water — minimum 1 bar supply pressure required. No break tank or header tank needed
- System connection: 15mm outlet to system; pipework in 15mm copper or approved plastic
- Tundish: Supplied ¾" BSP tundish must be piped to a suitable drain — cannot be capped or omitted
- Expansion vessel: A correctly sized expansion vessel must be fitted — vessel air/nitrogen pre-charge must match cold fill pressure setting
- Electrical: Permanent 230V 50Hz single-phase supply, fused at 3A; 12-way terminal block for BMS relay connections
- Pressure relief valve: A suitably sized safety valve must be fitted on all sealed systems — not supplied
- Installer: Must be a competent person complying with Building Regulations, IEE Wiring Regulations, and Water Supply (Water Fittings) Regulations
⚠️ Not suitable for outdoor installation or environments subject to excessively cold temperatures. For systems operating above 90°C, contact Mikrofill technical department before specifying. A pressure relief/safety valve must be fitted on all sealed systems — this is not supplied with the unit.
Technical Specifications
| Specification | Detail |
|---|---|
| Manufacturer code (MPN) | 120023 (also referenced MIK120023) |
| Brand | Mikrofill (Stuart Turner Group) |
| Type | Pumpless direct-type pressurisation unit |
| Application | Sealed LPHW and CHW systems — domestic & commercial, any size |
| Cold fill pressure (max) | 4.7 bar |
| Flow rate (nominal) | 14 litres/min at 2 bar supply pressure |
| Power supply | 230V AC, 1-phase, 50Hz — fused at 3A |
| Standby power consumption | 10W |
| Operating power consumption | 30W |
| Dimensions (H × W × D) | 270mm × 250mm × 112mm |
| Water connections | Inlet: ballofix isolation valve with basket filter · Outlet: 15mm isolation valve · Tundish: ¾" BSP |
| BMS relay outputs | 3 × volt-free contacts (low pressure alarm, high pressure alarm, common boiler/chiller interlock) — independently fused at 5A |
| Backflow prevention | Fluid Risk Category 4 (built in — no RPZ valve required) |
| WRAS approval | Yes — certificate number 1806078 |
| Standards | EMC Directive 2004/108/EC · LVD Directive 2006/95/EC · ISO 9001 |
| Origin | Made in Britain |
| Warranty | 2 years |
FAQs
Does the Mikrofill 3 replace an RPZ valve?
No — the Mikrofill 3 incorporates its own Category 4 backflow prevention internally, which is sufficient for connection to LPHW and CHW systems under Water Supply Regulations. It does not contain an RPZ valve (and does not need one). An RPZ valve would only be required in addition if the wider site installation demanded it for other reasons.
What size expansion vessel do I need?
Vessel sizing depends on system water volume, operating temperature, cold fill pressure, and maximum working pressure. Mikrofill's technical department (03452 60 60 20) can advise. The vessel air/nitrogen pre-charge must always be set to the same pressure as the cold fill pressure setting on the Mikrofill 3.
Can one Mikrofill 3 serve multiple boilers or a large commercial system?
Yes — the Mikrofill 3 is described as suitable for LPHW/CHW applications of any size. For very large systems or those with exceptionally high refill demand, contact Mikrofill's technical team. Pre-commissioned packages with dual-unit configurations are also available where redundancy is required.
ℹ️ Technical support: Mikrofill Systems Ltd, Redditch — 03452 60 60 20.
- Type Mains & Pressure Boosting Pumps
- Vendor Stuart Turner
- SKU MIK120023
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