Engine heater SafeStart 721-734 series

Engine Heater SafeStart 721-734 series

With thermostat

The heater consists of a coolant chamber and a power connection box.


The heater consists of a coolant chamber and a power connection box. There are two two-phase thermal fuses and a thermostat in the connection box which measures the temperature on a metal plate between the connection box and the coolant chamber. The fuses in the heater prevent the heating element from failing due to overheating.

Install the heater according to the enclosed installation guide. Install ONLY the heater on vehicles listed in the installation guide. Installing DEFA heaters must only be executed by authorized garages.


Normal usage – DEFA engine heaters are designed for “normal usage.” DEFA defines “normal usage” as; 3 connections for 3 hours pr. Twenty-four hours for 150 days (5 months) a year.

Professional use – For use emergency vehicles or other vehicles where the heater is in use continually, yearly controls are necessary. It might be required to install a replacement heater. DEFA AS will not cover the yearly service cost.

NOTE! Pulse power – Some parking facilities use interval (pulse) power timers that turning the power On and Off several times per hour. Using a DEFA engine heater in combination with these timers is NOT considered “Normal use” and claims will be declined.

Technical description

Up to 25 pr. pack, depending on the size of the heater.

Required and adapted connectors, screws and hoses are supplied with the heater.

DEFA AS conforms to the requirements of both ISO 9001- 2008, ISO 14001:2004 and OHSAS 18001:2007. In addition, our engine heaters and cables conform to the requirements of ISO/TS 16949:2002.