Electro Industries WARMFLO II, Installation And Operations

01/10/2008 7 

HI321 

Caution – 24 volts common grounding – 

the installer must determine whether the furnace fan 

center COM screw terminal has a good ground bond (not simply furnace skin).  If the fan center 
COM is not adequately grounded, use the pigtail green wire (WarmFlo board, upper, C tab) for a 
ground bond to the Electro-Mate cabinet power source ground lug.  The upper right circuit board 
mounting screw is a static ground protection point. 

CONTROLLER SETUP OR PROGRAMMING 

RV Logic Selection, Setup Required 

 
Since this model uses the reversing valve thermostat wire to disable WarmFlo and the gas furnace during 
cooling, it is extremely important the installer knows the RV logic of the installed HP unit and the pin 
jumper at the center top of this controller board is properly selected. 
 

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The HEAT and COOL represents when the reversing valve is high or at 24 volts.  Example – 
pin jumper between center and “COOL” means the reversing valve wire is at 24 volts during 
cooling. 

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The factory default is pin jumper setup for cool = high. 

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Important

 – if there is operational difficulty during defrost with the reversing valve (O) wire 

changing states during defrost or a RV logic high during heating application using stat B 
screw, you must have a wire connected to the DF (W1) tab representing a high voltage during 
the outdoor unit defrost mode.  A high input at the DF (W1) tab disconnects the RV (O) input 
wire and also affects the WarmFlo “E” tab. 

Using roomstat “B” function for units which are setup as heating = high RV logic

 – with this 

arrangement you 

must

 provide the shorted pin jumper on the upper left side of the board marked “Stat-

B”.  When received or all applications using cooling = high RV logic, the two pegs are open and the pin 
jumper is simply “hanging” on one of the pins.  For this application the two pins must be shorted.