Engine Heater SafeStart 420-423 series

Hose heaters - incl thermostat

DEFA number series 420 to 423 are a sub-category of series 400


DEFA has focused on easy installation and optimal heating functionality during development of engine preheaters. For different engine and vehicle combinations DEFA has 9 primary heater elements with more than 500 variants and over 5000 individual applications.

DEFA 420, 421, 422, 423 are distinguished from the other series 400 heaters by two basic differences: The heating element is completely surrounded by a coolant chamber. The heating temperature is limited by a built-on thermostat. The thermostat regulates the coolant temperature and switches off the power supply to the element when the coolant has reached a temperature of 80°C at the intake/outlet of the heater. The thermostat switches the heater back on at 70°C.

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.

Usage definitions

Normal usage – DEFA engine heaters are designed for “normal usage”. DEFA defines “normal usage” as; 3 connections for 3 hours pr. 24 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 necessary to install a replacement heater. Yearly service cost will not be covered by DEFA AS.

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-pack, depending on the size of 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.

IP rating