Water heater manufacturer case study

Magcat maintained full heater efficiency for 12 months in 280 ppm hard water, with zero scale formation.

Region: United Kingdom
Application: Water heater protection in hard water area
Sector: Commercial
Product: Magcat water conditioner

A leading global water heater manufacturer was seeking a reliable conditioning solution for installations in hard water areas. Traditional conditioners had produced inconsistent results, often leading to reduced efficiency and costly maintenance within just a few months of operation.

The challenge

Water heaters operating in hard water areas (above 150 ppm) typically begin losing efficiency within six weeks

The manufacturer required a conditioner that was cost-effective, long-lasting, required minimal to no maintenance, and consistently performed with no upper hardness limit

The selected heater featured a stainless steel heat exchanger, pre-mix zero governor burner, turbo fan system, a maximum set temperature of 85°C, and 96% gross efficiency with a 10-year expected lifespan when adequately protected

The solution

Two sites were selected with a hardness of 280ppm and 366ppm, respectively

A single ¾” Magcat conditioner was installed with a minimum one-metre run between the unit and heater inlet to allow effective treatment and maximise treatment performance at each site, operating at a set temperature of 65°C

Both trials were scheduled to run for 12 months; the site with a hardness of 280ppm was installed in August 2024, and the site with a hardness of 360ppm was installed February 2025

Results after six months

After six months of continuous operation, the efficiency of the heat exchanger was assessed using temperature readings taken directly from the water heater.

Results after 6 months: 366ppm

Water heater set temperature: 65°C

Point 2 – Hot water outlet thermistor – 65 = 65°C

Point 11 – Heat exchanger exit thermistor – 65 = 65°C

Results after 6 months: 280ppm

Water heater set temperature: 65°C

Point 2 – Hot water outlet thermistor: 64°C

Point 11 – Heat exchanger exit thermistor: 65°C

When checking for limescale within a water heater, the key comparison is between the set temperature and readings from Point 2 (outlet) and Point 11 (heat exchanger exit). When the water heater operates at 60°C or higher, all three readings should remain within ±1°C of each other.

If Point 11 is higher than Point 2, it indicates scale formation, as limescale acts as an insulator, forcing the heater to overwork in order to transfer heat, which can lead to overheating and eventual failure.

In both trials, Points 2 and 11 remained within the correct parameters, with Point 11 matching the set temperature exactly. These readings confirmed no signs of limescale formation after six months of continuous operation in either site.

Stamford site update

Reading: Stamford – 366 ppm hardness (after 6 months of catalytic treatment)

Water heater set temperature – 65°C

Point 2 – hot water outlet thermistor – 65 = 65°C

Point 8 – cold water inlet thermistor – 19 = 19°C

Point 11 – heat exchanger exit thermistor – 65 = 65°C

Correct flow sizing and a minimum ~1m pipe run before the heater are critical for catalytic performance and effective treatment. Consult the manufacturer for sizing guidance.

Findings after 12 months: 280ppm

The heat exchanger was removed and cut open for inspection

After one year of continuous use at 280 ppm, no hard scale was found

Surfaces remained clean, confirming complete prevention of limescale formation

The 366 ppm site will not be cut open until February 2026, as its conditioner was installed in February 2025.

Heat exchanger after 12 months of continued use

The following data was extracted showing peak performance was maintained after 12 months.

Water heater set temperature – 65°C

Point 2 – hot water outlet thermistor – 65 = 65°C

Point 8 – cold water inlet thermistor – 19 = 19 °C

Point 11 – heat exchanger exit thermistor – 65 = 65°C

Comparison

A competitor’s conditioner was tested under identical conditions at a separate site

After only three months, efficiency had declined and the heat exchanger showed significant scale accumulation

Heat exchanger after 3 months using a competitor’s conditioner

Magcat: scale-free after 12 months vs competitor: heavy scale after 3 months

Outcome

Magcat provided a maintenance-free, chemical-free solution that kept the heater operating at peak efficiency for 12 months in very hard water, outperforming alternative conditioners by a wide margin.

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