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EHS Primus 14kW Range-rated Single-Phase Electric System Boiler | 5-Yr Warranty
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Regular price
£1,170.00
Inc. VAT
£975.00
Exc. VAT
Sale price
£1,425.00 Inc. VAT
£1,170.00
Inc. VAT
£975.00
Exc. VAT
Regular price
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The EHS Primus 14000S Flex is a 14kW range-rated single-phase electric system boiler built as a direct, no-flue replacement for a gas system boiler. It connects to your existing radiators or underfloor heating using the same pipework, powered by a standard 230V electricity supply.
Unlike a fixed-output boiler, the Flex lets a qualified installer step the maximum heating output down from 14kW to 11.7, 9.3, 7, 4.6 or 2.3kW to match the property's calculated heat loss. One boiler therefore suits a wide range of homes, with less cycling and a supply that can be sized to what the house really needs. With no combustion, no gas connection and no flue, there is zero carbon monoxide risk and the unit can be sited with far more freedom.
For hot water, pair it with a separate vented or unvented indirect cylinder (not included). Heating the cylinder on an off-peak or night-rate tariff keeps running costs down, and the boiler is ideal alongside solar PV when used with a cylinder.
2.3–14kW
Range-rated output
230V
Single-phase supply
5 Yrs
Manufacturer warranty
0
Flue or gas connection
30–80°C
Radiator flow range
5L
Built-in expansion vessel
What range-rated means
The boiler ships with a maximum heating output of 14kW. A qualified electrical installer can reduce that ceiling in six steps (2.3, 4.6, 7, 9.3, 11.7 or 14kW) using the manufacturer's installer support, so the boiler, cable and breaker can be matched to the heat loss calculation and the incoming supply.
Safety and installation
Installation must be carried out by a qualified heating engineer and a qualified electrician in line with BS 7671, Building Regulations and Water Fittings Regulations. Never connect the boiler to mains power while it is dry – it must be filled and pressure tested first. The thermostat connection is zero volt only: any live supply to it will damage the main circuit board and void the warranty.
Required for the warranty
An automatic bypass valve, an inline magnetic filter on the return and a central heating inhibitor are mandatory, along with full-bore isolation valves and a WRAS-approved filling loop. Annual servicing by a qualified engineer and warranty registration within 30 days of installation are also required.
How it fits your system
The Primus 14000S Flex replaces a gas system boiler on the flow and return of an existing wet heating circuit (G3/4" male connections), so radiator and pipework changes are normally unnecessary. The 5 litre expansion vessel, ERP pump, pressure gauge, 3 bar pressure relief valve and automatic air vent are already inside the casing.
Control it with an external RF or Wi-Fi programmable thermostat via the zero-volt connection. Underfloor heating is supported through the boiler's low-temperature UFH mode (30–60°C), while radiator mode runs from 30–80°C. Frost protection runs automatically as long as the boiler stays powered.
Key features
Range-rated heating output
Set the maximum output to 2.3, 4.6, 7, 9.3, 11.7 or 14kW to match the home's heat loss and the available supply.
Integrated pump & vessel
ERP pump and 5 litre expansion vessel are factory-fitted, cutting parts and install time.
Pre-wired and compact
Pre-wired with a 650mm supply cable already connected inside the boiler, so there is no need to open the cover for the mains connection.
No flue, no gas
Zero carbon monoxide risk, no flue routing and no gas supply, giving flexible siting around the property.
Vented or unvented cylinders
Works with vented and unvented indirect cylinders, with off-peak tariff heating and solar PV integration via the cylinder.
Built-in protection
Frost protection, flow switch and thermal cut-out, a child lock and a front control panel with 24-hour timer.
Range-rating options
Always confirm the actual draw with a clamp meter after setup, and carry out a voltage and load test before choosing cable and breaker. An upgrade to the property's main fuse may be required at the higher output steps.
Technical specification
Frequently asked questions
BTU & WATT Calculator
Room Dimensions
Room Type
Living Room
Bedroom
Kitchen
Bathroom
Conservatory
Hallway
Glazing Type
Single Glazed
Double Glazed
Triple Glazed
External Walls
0 Wall
1 Wall
2 Walls
3 Walls
4 Walls
Insulation Level
Poor
Average
Good (New Build)
Required Heating
0
Watts
0
BTUs
Tools & Kits
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