Heat-Timer® Corporation

DIGI-SPAN® MC-Elite Series

Modulating Controls for Current, Voltage, and 135 Ω signals


Simple Affordable Modulating Set Point or Reset Controls for Temperature or Pressure. Well suited for radiant and process applications, the MC-Elite changes the position of a valve, burner, or variable speed drive in response to changes in sensor readings.

Temperature, Pressure, Vacuum, or Humidity. The same MC-Elite control can be connected to an array of temperature, pressure, vacuum, and humidity sensors. This makes stocking MC-Elite easier than ever. Each MC-Elite is field selectable for a broad range of parameters. Just select or stock the sensors you need with your control.

Standard and Customizable Reset Ratios. Utilizing the standard outdoor reset ratios or set point is built-in the MC-Elite. In addition, the controls come with a customizable reset ratio for applications where a standard reset

ratio would not suffice.

Enable/Disable. No Need to turn the control power off. The Enable/Disable terminals allow the use of external devices or switches to activate/deactivate the control operation.

Simplified Menus on an Easy-to-Read 2-Line Digital Display. Now, with two 16 alphanumeric line display and easy-to-ready menus makes setting and understanding control operation a snap.

Sensor Fault Output Status Selection. A feature that allows the user to select the output status when the sensor is disconnected or its reading is faulty.

Can be Powered by 120VAC or 24VAC. The Elite Series is normally powered by 120VAC. However, it has an alternative 24VAC power inputs. No transformers are required.

Radiant Heating. The MC-Elite Series can control a mixing valve to regulate the temperature of the water entering the radiant tubing.

Hydronic Heating or Cooling Loops. The MC-Elite Series can control either a mixing valve or a diverting valve to regulate the temperature of a hydronic loop.

Steam to Water Heat-Exchangers. The MC-Elite Series provides precise temperature control of water by controlling the amount of steam entering the heat exchanger.

Variable Speed Drive. The MC-Elite Series can be used to control the speed of a fan or pump to maintain a desired system temperature or pressure.

Modulating Burner Control. The MC-Elite Series controls the firing rate of a modulating boiler to maintain a desired system temperature or pressure.

Air Damper Control. The MC-Elite Series adjusts the opening of an air damper to control the space temperature or humidity.

  • Built-In Outdoor Reset
  • Customizable Reset Ratios
  • Muliple controls that can fit every hydronic steam or vacuum heating or cooling application
  • Built-in System relay
  • The same control can be used with avriety of sensors
  • Can be powered by 120VAC or 24VAC without the use of external transformers
  • Can be controlled remotely using an Enable/Disable input
  • Now with adjustable manual modulation for ease of service
  • Self diagnostics
  • Solid state sensors can be extended up to 500′ from the control
  • Accuracy of ±1ºF or 1% of full scale
  • UL Listed

MC-Elite Series Controls DO NOT COME WITH SENSORS.

MCA-Elite (4-20mA, 0-5V, 0-10V, 1-5V, 2-10V signals) 929160-UA
MCP-Elite (135 Ω signal) 929165-UA
MCF-Elite (floating signal) 929190-UA
Brass Tube Temperature Sensor 904250-00
3-in-1 Temperature Sensor 904220-00
3/8″ x 1/2NPT Well 904011-00
Humidity Sensor 904035-00
Vacuum Sensor 904317-00
Pressure Sensor 0-30 PSI 904310-00
Pressure Sensor 0-100 PSI 904312-00
Pressure Sensor 0-200 PSI 904311-00
Pressure Sensor 0-300 PSI 904313-00
Digi-Elite Wiring Enclosure with a switch 929135-00
Digi-Elite Wiring Enclosure without a switch 929137-00

My hot water outdoor reset control is giving me too much heat. What should I do?

Check if the control has any of the following:

  • Reset Ratio and Offset – If excessive heat occurs only in certain weather conditions, adjust the Reset Ratio and Offset. If excessive heat occurs year round, reduce the Offset.
  • Boiler Mode Settings – The control will only operate boilers their mode is set to Auto or Standby. Check to if any boiler stage is set to Manual or On.
  • Multi-Stage Control Settings – The Last-Stage-Hold will allow only the Lead boiler to stay on for an additional number of degrees. If the setting is too high, and only the Lead boiler is on, the system can over heat. Reduce the Last-Stage-Hold setting.
  • Domestic Hot Water Call – On a DHW call, the System Set Point will rise to the DHW Set Point or 200°F. If the increase in temperature is during DHW call, see about using any of the DHW Priority options available on the control.

At times I notice the pressure reading on my Heat-Timer Multi-MOD is slightly above the pressure set point. Does this mean there is something wrong with the Multi-MOD?
The set point on a Multi-MOD is not a high limit as it is on many other pressure controllers. The Multi-MOD is designed to control multiple full modulation burners to maintain a given system pressure (or temperature), not to be used as a system high limit. The Multi-MOD will not necessarily bring the boilers down to low fire as the pressure approaches the set point. Instead, the set point of the Multi-MOD is the average pressure the Multi-MOD will modulate the boilers to maintain. Therefore, it is perfectly normal for the pressure to rise slightly over the set point. Set the Multi-MOD set point to the pressure you would like the system to hold, not the maximum pressure the system should reach.

My outdoor sensor reading does not match the actual temperature.
The outdoor sensor measurement may vary based on its location and its sun exposure. In most cases it will never match a weather station that is located several miles away. most current Heat-Timer controls have a Trim feature which allows the sensor reading to be slightly modified just a few degrees to satisfy similar circumstances. If the difference was large, then check the sensor by disconnecting one of its wires from the control. The control should read OPEN. If not, contact technical support.

Why is my temperature sensor reading Open on the control display?
Remove the sensor wires from the control and check for continuity across the wires with and meter. If no continuity existed, check or replace the wires. if continuity did exist, then contact technical support.

Why is my temperature sensor reading Short on the control display?
Remove one of the sensor wires from the control. The control display should change and display OPEN. Then check the sensor wiring specifically around spliced areas. If wiring was good, then disconnect the sensor wires from the control and check the sensor wires with an Ohm meter. The readings should match the sensor temperature chart on the control manual. It not, then replace the sensor. If after removing one of the sensor wires the control read SHORT, then contact tech support.

  • Download the MC-Elite in Google Sketchup 3D format by clicking here.
  • Download the Wiring Enclosure Elite in Google Sketchup 3D format by clicking here.

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