Tec-Note: Troubleshooting modulation motors

Publication No. 1-07-184
download this Tec-Note in PDF format

Pages: 1, 2, 3, 4, 5, 6, 7, 8

Figure 2. Top view of Honeywell mod motor M7284C-1000.

Model Differences
The following table identifies the models of mod motors used on Heatec HC and HCS heaters that have modulating burners. There are important differences in the way the switches and cams are configured. Figure 2 shows the motor now used.

Key differences	Honeywell mod motors
Key differences	M7284C-1000	M9174C-1025	M9184F-1034
Heatec heaters used on	HC & HCS 12-06 & after	HC & HCS prior to 12-06	HC & HCS early units with modulating burners
Color of low-fire cam	Red	Blue	Red
Wiring of low-fire proof switch	Normally closed	Normally open (held closed)	Normally closed
Wires used, low-fire proof switch	Red=common Yellow=Normally closed	Red=common Yellow=Normally open	Red=common Yellow=Normally closed
Color of high-fire cam	Blue	Blue	Blue
Wiring of high-fire proof switch	Normally open	Normally open	Normally open
Wires used, high-fire proof switch	Black/red=common Black/blue=Normally open	Black/red=common Black/blue=Normally open	Black/red=common Black/blue=Normally open
Resistor board or resistor harness	(Not used)	Yes	Yes

← previous page next page →