Instruction manual
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APPENDIX A – OIL BOILER IQ CONTROL SYSTEM
IQ Control System Overview 
MPO-IQ Boiler uses a microprocessor based control system called the "IQ Control System". This "IQ Control System" consists of an 
IQ Oil Boiler Control in conjunction with an Oil Primary Control and an IQ Option Panel with optional "plug-in" IQ Option Cards.  
The IQ Control System fully integrates both factory and eld installed components, simplifying installation and troubleshooting.  
IQ Control System is designed to efciently operate the entire boiler system to save energy and installation and setup time, while 
ensuring adequate supply of heat and domestic hot water.
The IQ Option Panel works together with the IQ Oil Boiler Control to provide an easy and convenient means to "plug-in" an Auxiliary 
High Limit, Low Water Cut-off, and/or Outdoor Reset functions.
The Manual Reset Low Water Cutoff and High Limit IQ Option Cards are CSD-1 compliant, which simplies installations in areas 
where CSD-1 is enforced. IQ Option Cards snap onto the IQ Option Panel supplied on all MPO-IQ boilers and feature Plug n' Play 
connections.
IQ Oil Boiler Control: P/N 103851-01
The IQ Oil Boiler Control replaces the familiar Honeywell L7248 electronic Aquastat and contains several additional features. These 
unique features allow the IQ Oil Boiler Control to connect the boiler's control system together in a way that was not previously 
possible, greatly simplifying set-up and troubleshooting of the boiler.
IQ Option Card Major Features
• Plug-’n-play connection to MPO-IQ Boilers, only wiring required is to eld installed sensors
• Status and error codes displayed on built-in 3-digit display 
• Optional LCD touch screen display can also be used to read status and make adjustments
• Error codes can be displayed on EnviraCOM-enabled programmable thermostat
• Built-in diagnostics
• U.S. Boiler Company factory engineered and tested as part of a complete system
 LED display provides the following information:
 - Boiler Status - Standby, pre-purge, post purge, trial for 
 ignition, running, etc., 
 - Diagnostics - CAD cell resistance, run time hours and 
 cycle counts 
 - Error Monitoring - Including primary control and 
 connected IQ Option Cards 
 (Note: Primary control information is only available when 
 an EnviraCOM enabled primary is connected)
• Outdoor Air Reset Ready - Operating Setpoint is 
 automatically adjusted by outdoor air temperature and heat 
 demand type when an Outdoor Air Reset IQ Option Card 
 is connected. Also, Operating Setpoint is adjusted by 
 thermostat “sleep” and “leave” modes when a setback 
 EnviraCOM enabled thermostat is connected. 
• Warm Start Ready - boiler is started and circulator is stopped 
 when the boiler is cold and an external low limit is 
 connected.
• Smart Circulator Pre-purge - Upon a call for heat the 
 circulator is started and the boiler start is delayed. The 
 boiler is started without delay if the boiler is cold or there is 
 a DHW demand. Boiler cycling and resulting standby loses 
 are reduced by adjusting the circulator pre-purge time.
• "Energy Banking" Pump Overrun Time - The system 
 circulator may be run after the call for heat has ended to 
 “move” residual heat in the boiler to the system or indirect 
 water heater. 
• Second Congurable Pump Output - In addition to the 
 system pump output the control has a second pump output 
 and associated input that may be congured for Domestic 
 Hot Water or second zone demand and pump control. This 
 second output eliminates the need for an external relay for 
 DHW pump control or the need for a zone panel used for a 
 two zone home.
• Boiler System Display - well-known electronic aquastat 3-digit










