Try this link for service manuals: http://www.desaparts.com/service_manuals.html
If the unit runs for just a few minutes you could have a bad safety switch but you need to make sure you have the correct pump pressure.
Try putting your finger over the pump adjustment screw and see if you hear the heater become louder. If you do not hear a change in the sound of the heater you may have a problem with your end cover or pump pressure.
If you still need help you can call customer service at 1-800-475-5660
Answers & Comments
Try this link for service manuals:
http://www.desaparts.com/service_manuals.html
If the unit runs for just a few minutes you could have a bad safety switch but you need to make sure you have the correct pump pressure.
Try putting your finger over the pump adjustment screw and see if you hear the heater become louder. If you do not hear a change in the sound of the heater you may have a problem with your end cover or pump pressure.
If you still need help you can call customer service at 1-800-475-5660