Broan D SERIES ELECTRIC FURNACE General Requirements And Specifications Cont’D, Operating Options

GENERAL REQUIREMENTS AND SPECIFICATIONS (CONT’D)

		240 VOLTS – SINGLE PHASE				TEMP. RISE @ 0.20 IN. W.C.
MODEL NO.	KW	BTUH	AMPS INCL. MOTOR	HP	BLOWER	°C	°F	*SPEED	RPM
21D10	10	34120	46	1/3		21	70	MED-LOW	814
21D15	15	51180	67	1/3		24	25	MED-LOW	814
21D18	18	61420	77	1/3	10” x 8”	27	81	MED-LOW	814
21D20	20	68240	86	1/3	(254 mm x 203 mm)	33	91	MED-LOW	814
21D23	22.5	76842	94	1/3		36	97	MED-LOW	814
21D25	25	85003	107	1/3		37	99	MED-LOW	814
21D27	27	92130	116	3/4	12” x 8”	36	97	MED-HI	707
					(304 mm x 203 mm)
*FACTORY SETTINGS.
SUBJECT TO CHANGE WITHOUT NOTICE.

10” x 8” (254 mm x 203 mm) BLOWER

	FLOW		STATIC PRESSURE
SPEED		(INCHES OF WATER COLUMN)
	RATE
		0.2	0.3	0.4	0.5	0.6
LOW**	CFM	756	749	740	729	713
	L/s	357	353	349	344	337
MED-LOW	CFM	1035	1018	997	971	935
	L/s	488	480	470	458	441
MED-HIGH	CFM	1177	1157	1132	1102	1063
	L/s	556	546	534	520	502
HIGH	CFM	1301	1276	1247	1207	1145
	L/s	614	602	588	569	540

WARNING:

12” x 8” (304 x 203 mm) BLOWER

	FLOW		STATIC PRESSURE
SPEED		(INCHES OF WATER COLUMN)
	RATE
		0.2	0.3	0.4	0.5	0.6
LOW**	CFM	727	699	667	636	606
	L/s	343	330	315	300	286
MED-LOW**	CFM	912	897	878	853	823
	L/s	431	423	414	402	388
MED-HIGH	CFM	1216	1200	1181	1157	1129
	L/s	574	566	557	546	533
HIGH	CFM	1640	1601	1558	1513	1466
	L/s	774	755	735	714	692

**These speeds can only be run with heater off, for cooling/ventilation purposes only.

OPERATING OPTIONS

The furnace is shipped from the factory in a “Standard Heating Mode” (all switches in the Down position). When the thermostat calls for heat, the automatic controls will be activated and the furnace turns “ON”.

The blower will run at low speed or higher speed (as selected by

SPEED SELECTOR switch).

HIGH

LOW

SPEED SELECTOR

As the furnace heats up, it automatically switches to a medium speed when additional elements are activated by the electronic control, if it was initially set to run at low speed. The timing of this blower speed change will depend on whether COLD or MILD is selected on the SEASON SELECT switch.

You may, however, change from the Standard Heating Mode by using the controls built into your furnace.

MILD

COLD

SEASON SELECT

The SPEED SELECTOR switch is used to control the fan speed		During spring or fall, you may require less rapid response when
(ventilation). Even if there is no call for heat, the ventilation can be		the thermostat calls for heat.
controlled by the thermostat; the fan speed is determined by this		When MILD is selected, it takes more time to bring all the elements online.
switch.		When COLD is selected, the heating elements come online faster.
LOW – The blower motor will operate at low speed.
		MILD SEASON (First Stage)		COLD SEASON (Second Stage)
HIGH – The blower motor will operate at a higher speed.
		Slow Response Sequence		Rapid Response Sequence
		Element 1 - Heat on instantly		Element 1 - Heat on instantly
		Blower on after 3 seconds delay		Blower on after a 3 seconds delay
	Elements 3 and 5 after 1 minute delay		Elements 3 and 5 after 10 seconds delay
		Element 2 after 2 minutes delay		Element 2 after 20 seconds delay
	Elements 4 and 6 after 3-minute delay		Elements 4 and 6 after 30 seconds delay
	NOTE: Elements 4, 5 and 6 only where applicable.

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