Electro Industries WARMFLO II, Installation And Operations

01/10/2008  

HI321 

W

ARM

F

LO   

II 

Dual Heat System 

Furnace Interface Controller and Control Voltage Installation 

and Operations 

Application – Heat Pump Multi-Wire Thermostat 

Basic or Single Speed Heat Pump 

WF-LGR4 

As in previous interface modules, this is the plug-in controller for Electro-Mate EM-WU***** or EM-
WD***** plenum heater.  Mechanical installation information is contained within companion installation 
manual EI703 or EI707. 
 
Also accompanying each system is a specific control program “chip”.  This is typically part of ordering 
information and should be listed on packing slip.  A listing of these “chip codes” is in the controller setup 
sections of this document. 
 

This is an upgraded and improved WF-LGR3.  Improvements are the response of field requests. 

ƒ

Thermostat wiring terminal block, pass through 

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Improved stat emergency heat function, no longer requiring extra relay 

ƒ

Reversing valve detection relay, positive WarmFlo and gas furnace interrupt during 
cooling (RV logic pin jumper setup required) 

ƒ

Front panel “cool” light 

ƒ

Equipped for ECM blower motor, direct Y connection 

ƒ

Faster defrost response 

ƒ

Easier single cable plug-in to the upgraded (10-pin connector) WarmFlo II board 

Reference Field Service Bulletin 1094 which relates to heat pump units with RV logic high for heating – 
this unit identified as “Rev A” and has a control board identifier “WFIH46708A” includes revisions 
relating to stat emergency “E” hookup and operation, cool light function, etc.  Also study page 7, 
determine the need for “stat-B” pin jumper. 

Any application

 – 

this design assumes the connected room thermostat cannot and does not output an 

emergency “E” function during cooling.  During any and all cooling operations, this controller board “E WF” 
and “E GAS” tab must be at 0 volts. 
 

Drawings: 

HH340 

HD320 

HH339 page 1 

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