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Topic: Aquahot controller technical question (Read 225 times) previous topic - next topic

Aquahot controller technical question

First let me say, there is nothing wrong with my system. I was reading the AH technical service manual to learn more about the system, and had a question about a certain possible interlock the controller might or might not  have. (ref page 68 DC voltage checks and low voltage)

IF the supply voltage for the controller drops below 11.5 volts (Pin B4), will the controller stop the system from running?

As the manual instructs on how to check for low voltage or in turn low RPM related to low voltage. I am assuming the controller has no way of stopping the unit from running at any voltage.....But would like to know.


My system, AHE-100-02S
Mike in AL
2001 U295
8.3 ISC 350
Build 5918

Re: Aquahot controller technical question

Reply #1
The Control Unit that runs the burner looks at the voltage from the flame sensor to determine there is a fire.  When the incoming voltage to the burner gets below 11.5, it is easy for the flame sensor voltage to go below 10 volts.  The control unit will determine the flame is not sustainable at voltages below 10 volts.  The control unit then faults, turns off the fuel, cools for 3 minutes and stops the burner till someone turns the burner off and back on to remove the fault.

Newer heaters have an electronic control board to run the heater.  It has a low voltage light that will stop the burner during low voltage conditions.  A micro switch must be pushed to turn the low voltage light off to restore operation.
Rudy Legett
2003 U320 4010 ISM 450 hp
2001 U320 4220 ISM 450 hp
1995 U320 M11 400 hp
1990 Granvilla 300 hp 3208T
Aqua Hot Service Houston and Southeast Texas

 

Re: Aquahot controller technical question

Reply #2
Rudy,

Thank you for the detailed explanation.
Mike in AL
2001 U295
8.3 ISC 350
Build 5918