This document provides information for programing and re-tuning Honeywell UDC3300 controllers (Figure 1) used on Heatec HC and HCS heaters (Figure 2). It applies to all sizes of HC and HCS heaters.

This document along with Honewell manuals applicable to Honeywell UDC3300 controllers are furnished with Heatec HC and HCS heaters. Note: printed copies of Honeywell manuals are now being replaced with a computer CD, which contains PDF versions of their manuals. If you need help on how to use the buttons on the controller, please refer to the applicable Honeywell manual. You can call Honeywell for technical assistance at 1-800-423-9883. Their web site for assistance is www.honeywell.com/imc.

Before attempting to retune the controller make sure it is properly programmed. The settings that apply to Heatec HC and HCS heaters are shown in Figure 3, parts 1 and 2. The information shown in figure 3 is the same as that shown on the laminated sheets stored inside the control panel. In case there are any differences, use the information shown on the laminated sheets.

On many heaters the controller’s preset values provide satisfactory modulation control of the burner, so it is not necessary to re-tune it. However, it should be re-tuned if the temperature of the thermal fluid constantly overshoots its proportional band (PROP BD) causing the burner to frequently cycle on and off.

Re-tuning should be done only after the heater and thermal fluid circuits have been filled with thermal fluid and purged free of air and water.

There are two methods of re-tuning. One method is to use the Accutune function of the controller, which automatically tunes the controller. The other method is to manually reset three the functions shown in Figure 4. Again, do not re-tune the controller unless the heater shuts off and on frequently. Instructions for using both of these tuning methods follow.