From our technical experts

Thermalec In-Line Heater – LHR3 – 3kW


  • Thermalec Electric Heater
  • Thermal Efficiency
  • Easy to Install
  • Free Delivery
SKU: LHR3 Categories: ,


Thermalec In-Line Heater – LHR3 – 3kW

LHR3 – 3kW Thermalec in line heater – (1 phase)

Built in the UK with the exacting standards expected from Thermalec®, this range of smaller in-line heaters brings a cost effective solution to your heating requirements. All Thermalec in-line heaters use a proven coiled heating element technology that creates turbulent water flow rate through the heater, delivering the outstanding efficiency and extended life expectancy by preventing the build-up of mineral deposits on the heating element. A user friendly analogue or digital thermostat controller allows the desired pool temperature to be set accurately to within 1°C accuracy.

• Safe, reliable and easy to install
• Accuracy to within 1°C with analogue controller
• Titanium heating elements
• BS 316L Stainless Steel flow tube (EN1.4432)
• Flow switch operation
• Floor or wall mountable
• Control thermostat: Analogue, digital or Wi-Fi
• 100% operational efficiency throughout product life


The Thermalec sizing chart is for outdoor swimming pools in the South of England, running from the beginning of May until the end of September.
For swimming pools in the North, multiply the heater size by 1.3 – 1.5, depending on the exposure of the pool.
The figures shown for capacity of the pool – m³ – are based upon an average depth of 1.36m and are provided as a guide when an exact surface area is not known.
Indoor pools: providing the indoor air temperature is maintained at least 1°C above the pool temperature by an alternative form of heating 24 hours per day, the heater size may be reduced by multiplying by 0.7, but since running costs are related to the size of the pool and the temperature required, not the size of the heater, we advise keeping to the table where possible.
In countries where off-peak electricity is not available, heaters sized at 1kW per 1000 gallons (4500 litres) with the heater operating 24 hours per day, will normally be adequate and will give an 8°F (4.4°C) rise in 24 hours assuming no losses.

Additional information


120THR/84 Pool Volume 230m3, 120THR/96 Pool Volume 263m3, 120THR/108 Pool Volume 296m3, 120THR/120 Pool Volume 329m3, 120THRD/84 Pool Volume 230m3, 120THRD/96 Pool Volume 263m3, 120THRD/108 Pool Volume 296m3, 120THRD/120 Pool Volume 329m3

How to treat green water

Find out all you need to know about algae and green water, how to treat it and how to cure it.

Returns Policy

Your rights to return goods are protected under the EU Distance Selling Directive.

You are entitled to cancel your order and return the goods within 7 working days for a full refund not including the cost of delivery. Do this by contacting us by email or telephone and quoting the order number supplied to you. Your refund will be paid within 30 days. You are responsible for the cost and risk of loss or damage when returning the goods, so you should take out enough postal insurance to cover their value. This cancellation policy does not affect your rights when we are at fault - for example, if goods are faulty or incorrectly-described.

Exclusions: Bespoke items (made to measure items) are not included and cannot be returned. If a bespoke item is faulty then the product warranty /guarantee will take effect.

Any goods returned should be in saleable condition.

These terms apply to your order. We may change our terms and conditions at any time, so please do not assume that the same terms will apply in the future.

None of these terms affect your legal rights and these are not diminished in any way. If any term is held to be invalid under any applicable statute or rule of law, that term is automatically omitted from the terms to minimum extent necessary to comply with the law and without affecting the validity or enforceability of the remainder.

You may also like…