06-15-2013, 06:40 AM
Bob,
The diesel burner blower motor will stay on 2 to 3 minutes after the control unit (silver brain box) turns the fire off. This shut down purge cools the combustion system and flushes the system with fresh air. The purge cycle is a timed event and not controlled by a temp sensing thermostat. The blower could be described as an internal fan as it is inside of the burner.
The control unit stops the fire when the control thermostat reaches set point, high limit thermostat opens or you turn the diesel heat switch off inside the coach.
There are no other installed fans to cool the heater provided by Aqua Hot. Neither Ashley's or Chappell's heaters have an additional Newell installed fan as I have had eyeballs on both of those heaters.
The high limit thermostat is set well above 207 degrees F so it is not going bad. The control thermostat can fail closed and heat the heater up to the high limit set point. You would know the control thermostat had failed closed since all heating with the diesel burner would stop till you manually reset the high limit thermostat.
I do not recall if your 12 vdc high limit thermostat is resettable. There will be a reset button on it if it can be manually reset.
The diesel burner blower motor will stay on 2 to 3 minutes after the control unit (silver brain box) turns the fire off. This shut down purge cools the combustion system and flushes the system with fresh air. The purge cycle is a timed event and not controlled by a temp sensing thermostat. The blower could be described as an internal fan as it is inside of the burner.
The control unit stops the fire when the control thermostat reaches set point, high limit thermostat opens or you turn the diesel heat switch off inside the coach.
There are no other installed fans to cool the heater provided by Aqua Hot. Neither Ashley's or Chappell's heaters have an additional Newell installed fan as I have had eyeballs on both of those heaters.
The high limit thermostat is set well above 207 degrees F so it is not going bad. The control thermostat can fail closed and heat the heater up to the high limit set point. You would know the control thermostat had failed closed since all heating with the diesel burner would stop till you manually reset the high limit thermostat.
I do not recall if your 12 vdc high limit thermostat is resettable. There will be a reset button on it if it can be manually reset.
Rudy Legett
2003 Foretravel U320 4010
ISM11 450 hp Allison 4000R
Factory Authorized Aqua Hot Repair Center
Southeast Texas Area