No delay of Blower ON for Rheem electric furnace?

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Old 11-09-13, 12:18 PM
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No delay of Blower ON for Rheem electric furnace?

Rheem Electric Furnace/Model# RBHA-17j15sfa (an older unit)

Is it normal for this blower to not have any ON (start-up) delay when the t-stat turns the unit on? (compared to a standing pilot gas furnace that heats the heat-exchanger up first, then turns blower on?)
 
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Old 11-09-13, 03:01 PM
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http://www.rheem.com/documents/rbhk-...n-instructions


Heating (electric heat only)
• When the thermostat “calls for heat,” the circuit between
R and W1 is completed, and the heater sequencer
(HR1) is energized. A time delay will follow then: The
heating elements (HE) and the indoor blower motor
(IBM) will come on. Units with a second heater
sequencer (HR2) can be connected with the first sequencer (HR1) to W on the thermostat sub-base or
connected to a second stage W2 on the sub-base.W1 on the furnace board MUST be connected for heating blower operation.
If the thermostat is configured for electric heat, it will energize the fan immediately.
If the stat is configured for gas heat, the sequencer in the unit will start the indoor fan after a delay.
 
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Old 11-09-13, 05:44 PM
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On this particular unit, 24vac Red wire leaves transformer mounted on furnace cabinet, goes to t-stat, comes back on White wire from t-stat, connects to three individual wires at furnace cabinet, two of which feed the two heat sequencers (brass quick disconnects at base of sequencers) - the third one feeds the hot side of Fan Relay coil.

The opposite side of the heat sequencers (brass q-d's at base) and the common side of Fan Relay coil all connect to common of transformer mounted on cabinet.

As I've described the wiring connections above, the Fan/Blower will energize immediately with a call for heat, but there will be a slight delay (per the timing of the heat sequencer) of the first heating element(s) turning on. Correct? This would give an initial blast of room temperature air, before the sequencer energizes the first heating element(s). Is that normal/acceptable?
 

Last edited by plumducy; 11-09-13 at 06:09 PM.
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Old 11-09-13, 06:14 PM
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Does the diagram on the unit show the controls as you have them?

The drawback to your setup is the delay on break controlling the heats strips will be without fan operation when heating demand is removed.
 
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Old 11-09-13, 06:31 PM
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No wiring diagram for this unit. I believe this is a 15KW unit. It has a total of 3 individual heating elements (crescent moon-shaped), wrapping around the inside of the blower housing. I saw online where someone called them Calrode ( look like oven heating elements). Smaller mobile home.

I believe you're talking about when the t-stat shuts off the call for heat, the sequencers cool down in reverse order, and will be without the fan during the shut-down sequence. Two heat sequencers for this unit. Will that be a problem for this unit?
 
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Old 11-09-13, 08:53 PM
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This delay on break issue would be of greater concern to me than the lack of a delay on make.

I have seen that setup work for decades without issue but I wouldn't want it on my house. It would drive me even more crazy.
 
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