Mercian Electric Company Ltd

3, Lewisher Road,
Troon Industrial Estate,
Leicester, Leicestershire LE4 9LR
Tel: 07535 871996
Fax: 01509 816060

electric heater batteries, electric vent heaters, industrial heater batteries, electric heaters

Electric Heater Batteries, electric vent heaters, industrial heater batteries and electric heaters for the heating and ventilation trade.

We at Mercian are specialist manufacturers of electric air heaters for the air conditioning & process heating industries. We also supply electric heater batteries and industrial heater batteries.

All of our heaters are specifically designed to operate at Low Surface Temperatures (below 400 °C), giving each heater a very long working life and safe operation.

As a safety feature, every electric heater is fitted with a high temperature thermal trip to shut down the unit in the event of fan failure or low airflow situations. These thermal trips may be manual or auto-resetting to suit the application.

Two heating methods are utilised...


Spirals of Chromium resistance wire, wound to an exact load, are supported within ceramic formers and energised to give a very accurately controlled heat output. This system has the added advantage of a rapid heating/cooling response from the elements.


Sheathed elements are our most popular heating method and are usd to meet the property Service Agency "M&E100" specifications. Large numbers of elements can be banked together to give loadings of up to 400 kilowatts with a variable number of stages. This type of heater meets the British Standards and gives a superior working life and added safety.

Our Products...

Flange Mounted (Spiral Wire) Heaters


We have a standard range of spiral wire heaters with flanges on both faces, ranging from 150mm to 750mm square.

The units are fitted with resistance wire elements to meet the customer's exact specifications.

The cases are made from heavy gauge, stove enamelled steel, and are normally kept in stock for rapid customer response.

Flange Mounted (Incology 800) Heaters


These units can be made to comply with the 'M&E6' and 'M&E100' specifications incorporating stainless steel sheathed elements mounted on easily removable terminal plates. This allows for easier servicing and inspection of the elements without the need for removing the whole unit from the duct.

The heaters are specifically designed to operate with a surface temperature below 400 °C and incorporate an enclosed thermal trip with three pole contacts for use with an indicator light.

'Stab-in' (Spiral Wire) Heaters


We also carry a range of plates for the 'stab-in' style of heater. These can be rapidly assembled to suit the customer's duct height, width and kilowatt loading.

These heaters are ideal for providing extra heat in existing ductwork systems. The heater is simply inserted into a hole which has been cut into the side of the duct and the faceplate screwed into position. The thermal trip can be seen situated above the element banks.

'Stab-in' (Incology 800) Heaters


Sheathed elements may be mounted on a plate to form booster heaters in specific sections of existing ductwork.

in thie same way as the spiral wire heaters, a hole is cut in the side of the duct and the faceplate is screwed into place. This leaves the terminal box easily accessible to the site engineer.

The advantage of this method is the ease with which elements can be replaced for upgrading or lowering the heat output.

Cartridge or 'Slide-in' Heaters


These heaters are designed mainly for sliding into air handling units. The whole heater can be sealed inside, behind an inspection panel, to give an airtight seal.

The elements are mounted inside a rigid sheetmetal framework with a flat base to allow the unit to slide into position.

Cartridge heaters can be designed to any size or kilowatt loading to suit the application.

Circular Duct Heaters


We have a standard range of circular heaters, to suit all standard ISO spiral ductings from 100mm to 400mm diameter.

Each unit is manufactured from galvanised sheet steel with kilowatt loading and stages to suit the application.

The terminal box, with thermal trip and earth terminals inside, is mounted on top of the heater.

Email: Tel: 07585 871 996 Fax: 01509 816060

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Electric air heaters and control panels for the heating and ventilation trade As a safety feature, every heated is fitted with a high temperature thermal trip. Flange Mounted (Spiral Wire) Heaters Flange Mounted (Incoloy 800) Heaters 'Stab-in' (Spiral Wire) Heaters 'Stab-in' (Incoloy 800) Heaters Cartridge or 'Slide-in' Heaters