MPO-IQ Control
(prior to Sept 1, 2012)
As of Sept 1, 2012 the control parameters have changed to meet new federal compliance. Compare the control parameters between Pre and Post 9/1/2012.

The MPO-IQ control for the Burnham by US Boiler three pass oil boiler has some nice features built into the control. these features may save you some money on the installation and will add the system efficiency to save even more fuel dollars. The IQ control for the oil boiler is different than gas IQ control as far as available features.

The available selectable features are circulator pre-purge, circulator post purge, two input connections and two pump connections which can be used for Indirect water heater or second zone of heat, and frost protection. The IQ control also has adjustable parameters such as high limit, high limit differential, F or C. The IQ control utilizes Honeywell's 3 button press to enter parameter enter mode.


A quick explanation of these features are as follows;

HL - High Limit - shuts the burners down when the boiler water temperature reaches the high limit setting. Default is 180f. Range from 140f - 220f.

dF - High limit differential - When there is a heat or DHW demand and the boiler shuts down on high limit the differential is how far the water cools off before the boiler fires up again providing there is still a demand on the boiler. Range is 15f - 30f.

Pre-purge – If this feature is turned on, factory default is off you will be required enter a time between 1 and 30 minutes. When the boiler receives a call for heat and the boiler water temperature is above 140F, (next control version this will be adjustable) just the circulator will start and use residual heat from the last cycle first. The benefit of this is to allow the burner to have a longer run cycle. The burner will fire when the timer counts down to zero or the water temperature drops below 140f or the indirect water heater gives a call to the boiler. During the cold months this could count for about a 10% savings.

Post Purge – Pump Overrun Time (also called “off delay” or “post purge”) continues pump operation after a call for heat has ended, sending excess heat from the boiler into the priority zone.  Ensure system piping and zone panel settings allow water flow to the priority zone after the call for heat ends.  The  Pump Overrun Time has a factor setting of 0 minutes and is field adjustable between 0 and 10 minutes.

2 Zones – Choose ZC or ZR -You can connect two zones of heat or 1 demand for heat whether it be 1 thermostat, zone valves or a multi-zone relay and an indirect water heater. The IQ control will accept two inputs and control 2 circulators without any additional relays. If one of the inputs is an indirect water heater it also has priority. The use of a multi-zone relay for more than one heating zone would still be considered 1 zone of heat and the indirect water heater could still be wired directly to the boiler control.

Frost protection - When enabled, frost protection starts the boiler when the water temperature is below 40 F and stops the boiler when the temperature rises above 50°F. Frost protection only protects the boiler from freezing, circulators are not started due to frost protection. Frost protection may be enabled or disabled.

IQ control

The IQ control (boiler aquastat) is used in conjunction with the OCP (Optional Control Panel that will allow plug in modules which consist of pan Outdoor Reset manual or automatic reset Low Water Cut-off and/or automatic or manual reset secondary temperature limit. Some states and municipalities require Low water cut-off and/or secondary limit controls. The manual reset low water cut-off and manual reset high limit is CSD-1 certified. CSD-1 is a commercial requirement big feature of the US Boiler IQ oil control also offers status displays and troubleshooting. Included is communication cable which should be plugged into the right side of the boiler and to the primary control on the oil burner. The IQ control will display ERR (error) codes and also ERP (error codes on the primary control, and you can even read the resistance on the cad cell relay on the IQ control.


IQ and OCP Panels - No Optional Cards displayed
IQ Control Display
Error Codes on the IQ Control
If you had a new Burnham boiler installed recently click here

Disclaimer: The information found on this website is for informational purposes only. Any and all preventive maintenance, service, installations should be reviewed on a per job situation. Any work performed on your heating system should be performed by qualified and experienced personnel only. Comfort-Calc or it's personnel accepts no responsibility for improper information, application, damage to property or bodily injury from applied information found on this website as it should be reviewed by a professional.