Introduction

The customer approached Cotherm with an issue regarding the accuracy and consistent function of their current thermostat supplier. They experienced many issues with the operation of their existing part and reached out to Cotherm to find a solution. These issues were critical to the reputation of the brand, so accuracy and consistent operation were necessary.

Key figures

• Power ratings between 1.5 kw and 300 kw
• Temperature regulation at 49°C
• Pools and hot tubs as small as 300gals and as large as 100,000gals
• Hundreds of thousands of units sold

What is a Spa Heater?

Spa heaters are used to heat pools and hot tubs in both residential and commercial situations. Generally, spa heaters are used “in-line” with the water supply, heating the water as it enters the application. Spa heaters can be found in sizes as small as 1.5kw and as large as 300kw for large pools. While these devices seem simple, they contain multiple measures to ensure the correct water temperature is maintained for the comfort of the homeowner.

What are the challenges?

Spa heaters need to produce consistent hot water for the pool or hot tub, or else the average temperature will drop, and additional electricity and wasted water will be required to increase the temperature again. In order to keep up with the demand, the thermostat needs to be accurate and the temperature reading needs to be acted on quickly. This presents an engineering problem which needs a consistent and durable solution.

Relax with confidence using GTLs

Cotherm GTL bulb and capillary thermostats play a crucial role in pool and spa heaters. These mechanical thermostats are designed to regulate water and steam temperatures with precision and safety. You may see these devices regulate the temperature for optimal comfort, or they can be safety switches to prevent dangerous conditions. Often, you’ll see two GTL thermostats in an application, each doing its part to provide the best experience possible.

Why a GTL?

The pool and spa industry by nature has unique challenges for temperature control systems. First, these environments can vary drastically depending on the location or climate. Temperature and humidity fluctuations make it a requirement for these systems to be robust and ready for hard work.

Additionally, the materials used on the bulb and capillary need to be resistant to whatever conditions may be thrown at them. GTL products come in stainless steel or full copper, each with its own benefits for different applications. For example, in systems using chemicals like chlorine or bromine, it’s probably a better idea to use stainless steel.

Will GTLs become extinct?

Despite the growing prevalence of digital control in the pool and spa industry, mechanical thermostats are not going anywhere. Bulb and capillary thermostats have been in use for these applications since their invention, and there are reasons:

1. Simplicity and Reliability: GTL thermostats are a tried-and-true design, reducing the risk of failure and making it easier to troubleshoot and repair.
2. Cost-Effectiveness: Compared to digital alternatives, mechanical thermostats are significantly more affordable, which allows savings to be passed along to the customer.
3. Eco-friendly Manufacturing: GTL thermostats are generally more eco-friendly to produce than most mass-produced electronic controls in areas of Asia and Africa. Specifically, Cotherm’s manufacturing standards go above and beyond. (ISO 9001, ISO 14001)