Description

Envirostat FP4ER – 4kW Reverse Logic Frost Protection Controller

The Envirostat FP4ER is a 4kW reverse logic electronic thermostat engineered for energy-efficient frost protection. Unlike standard frost protection controllers, the FP4ER is designed for use with fans, automatically switching them off when ambient temperatures approach freezing point. This prevents cold air circulation that could lead to frozen pipework or system damage. As part of the FP4R series, the FP4ER provides straightforward reverse logic control, while the FP4iR adds additional alarm and monitoring features.

The Envirostat FP4ER delivers energy-efficient frost protection with reverse logic control, making it ideal for HVAC systems and fan applications. When ambient temperatures approach freezing, the FP4ER switches fans off, preventing circulation of cold air that could lead to pipe freezing or equipment damage.

It includes a 2m encapsulated temperature sensor, soft start function to reduce inrush currents, and a temperature range of -10°C to +10°C (0°C to +20°C available as an option). With solid-state reliability, IP65 ingress protection, and a 20A current capacity, it is built for durability in industrial and commercial environments.

For advanced monitoring, the FP4iR model adds output and load fault detection plus LED indicators, offering extra assurance in critical applications.

United Automation’s Envirostat Frost Protection Controllers are trusted worldwide to prevent frozen pipes, control outdoor pipe heating, and support systems in the fight against Legionellaceae.

Applications

• Fan systems requiring shut-off near freezing conditions

• Frost protection for HVAC installations

• Industrial and commercial pipework systems

• Building management and air-handling units

• Refrigeration and cold storage facilities

Features & Benefits

• Reverse Logic Function – switches fans off near freezing temperatures

• Simple Setup & Installation – quick to configure and deploy

• 2m Encapsulated Sensor Included – ensures accurate monitoring

• Soft Start Function – reduces inrush current, extending component life

• Temperature Range – -10°C to +10°C (0°C to +20°C available on request)

• Solid-State Reliability – robust, maintenance-free operation

• IP65 Protection – dust- and water-resistant, suitable for harsh environments

• High Current Capacity – supports up to 20A for demanding systems

• FP4iR Only – adds output & load fault detection plus LED indicators

Specifications

Typical Applications

• Reverse logic frost protection for HVAC fans

• Protection of air handling units in cold environments

• Industrial and commercial pipe freeze prevention

• Fan shut-off in building services and automation systems

• Refrigeration, warehouse, and cold storage frost protection