Guidelines for immersion heater installation into boilers, autoclaves, sterilizers and other water heating applications where a mounting flange and gasket are required.

Air Heater Care and Maintenance

The life of air heaters can often be extended by periodic maintenance.  Over time, deposits of dust, lint, and other materials build up on the air inlet side of the heater.  This build-up reduces the efficiency of the heater.  This material is a thermal insulator and restricts the heat energy from actually reaching the moving air.  Since the air doesn't heat efficiently, the heater is working more than neccessary and will eventually overheat itself and burn out.  If designing an air heater into a new product, consider adding a filter in the inlet side of the air stream that can easily be cleaned or replaced.


Factors that make this situation worse:

  • Dusty areas or areas where pets shed their fur.  This is often an environmental situation that can't easily be resolved.  Air filters on the air inlet will help if they are cleaned regularly.  Placement near to the floor tends to cause the pickup of more material.
  • High watt density on the surface of the resistance wire.  This is a design issue that is generaly restricted by space constraints.  A high power heater in a small physical space creates this situation.  Our heaters are designed to have as much surface area as possible and still fit inside the available space, but we cannot change the physics of surface area/power.
  • Over-voltage supply and spikes.  These also often can't be controlled, but never use a heater at more than it's rated voltage.  Over-voltage conditions increase the power output significantly beyond what the heater was designed for.  See the point above for what happens.  Under-voltage is OK, but the reduced power might cause increased heat-up time and process times.
  • Poor air circulation or low air flow.  Either of these situations will cause overheating at a very localized area where the flowing air is not removing heat from the resistance wire.  An air filter (see the first point) that is not regularly cleaned will restrict incoming air flow.
  • Infrequent cleaning.  This is something that can be controlled.  Periodic removal and cleaning of built up lint, dust and other material is mandatory and should be planned as normal periodic maintenace.  The schedule for this maintenance will be determined by the factors previously mentioned.  When replacing or cleaning heaters, remember to disconnect the electrical power and properly lock out the equipment.  Care must be taken not to damage the resistance wire or electrical connections.