Cotherm Resource Blog

Interesting articles offering help and insight into past, current and future plumber and heating issues.

Cotherm at your side since 1948


As a leading global company within the heating, ventilation & air conditioning (HVAC) industry, we have the experience, the presence and the resources to make a difference, and that is exactly what we are doing. 

Get In Touch

Browse Cotherm's Resource Blogs

Heating, ventilation, air conditioning & plumbing control solutions

Browse Cotherm's Resource Blogs

Heating, ventilation, air conditioning & plumbing control solutions

How to safely Test an immersion heater element for a hot water cylinder.

How to test if a hot water cylinders immersion element is faulty

By Wayne Harrhy • December 8, 2025
A blog on how to safely test if a hot water cylinders immersion element is faulty or working correctly. There is also helpful tips on what else could be faulty such as the rod thermostat. Cotherm (UK) Ltd.
How to test a plug in immersion heater thermostat, to test if faulty or working correctly.

How to correctly test if a Cotherm TSE or TSR plug in type immersion thermostat is working or not?

By Wayne Harrhy • October 20, 2025
No hot water from your hot water cylinder? This article explains how to correctly test if a plug in Cotherm TSR immersion rod thermostat or a plug in Cotherm TSE immersion rod thermostat is faulty or working.
Why are the Cotherm TSE & TSR thermostat terminals marked A & B?

Why are the Cotherm TSE & TSR thermostat terminals marked A & B?

By Wayne Harrhy • August 20, 2025
On a Cotherm thermostat, the terminals are marked A and B to denote the electrical live input and output, respectively, for a simple switch circuit. Specifically, A is the Live (Brown) connection that receives power, and B is the Neutral (Blue) connection that the thermostat switches.

A Success Story

Cotherm 75 years of experience

The creation of Cotherm!

International expansion : The set up of the UK sales office, which developed into a sales, distribution and assembly site.

1st Electronic controller : This was also a time of expansion with the set up of the Tunisian factory and the USA sales office.

The roll out of the industry leading Smart hybrid control.

Energies saving technologies : Leading the way with Heatpump technologies - Renewable energies.

Digitalisation : loT Connected controllers - Automation - NCF - Heating elements.