Circuit Examples - PENN Controls - A19BAC - A28AA - Electromechanical Temperature Control - A19 Coiled Bulb Control - A28 and A36 Multi‐Stage Temperature Control

A19BAC, A28AA Single and Two-Stage Space Thermostats for Farm and General Purpose Applications Installation Guide

Brand
PENN Controls
Product name
A19 Coiled Bulb Control
A28 and A36 Multi‐Stage Temperature Control
Document type
Installation Guide
Part number
996-238
Document revision
F
Revision date
2019-03-07
Language
English
Figure 1. A19BAC typical heating control circuit

Figure 2. A19BAC typical ventilating or cooling control circuit

In Figure 3, RBH, RYH indicate HI-TEMP. RBL, RYL indicate LO-TEMP. D is the differential between stages.

Figure 3. Switch action of the A28AA two-stage control

Figure 4. An A19BAC in control of heating and ventilating systems

Figure 5 shows typical wiring for the control of a two speed ventilating fan. When control temperature reaches the dial setting, the low temperature switch starts the fan on low speed. If the space temperature continues to rise, the high temperature switch supplies power to the high speed motor winding while disconnecting the low speed winding.

Figure 5. A28AA wiring for control of a two speed ventilationg fan

Figure 6 shows a typical hookup for a two speed volume fan application. The fan starts when the temperature reaches the dial setting. If the temperature continues to rise, the damper motor is energized by the high temperature switch.

Figure 6. Typical hookup for a two speed volume fan application

Figure 7 shows typical wiring for a combination heating and cooling system automatic changeover. A temperature increase to dial setting turns off the heating system when the R-B low temperature switch contacts open. An increase of approximately 3F° (1.7C°) turns on the fan or cooling system through the R-Y contacts of the high temperature switch.

Figure 7. Typical wiring for a combination heating and cooling system automatic changeover

Figure 8 shows a typical hookup for two stage heating. On a temperature drop to dial setting the first stage heating turns on. If the temperature continues to drop about 3F° (1.7C°) the second heating stage turns on.

Figure 8. Typical hookup for two stage heating