Blower motor died on a 18 year old Furnace: Update 2

vferdman · 2005-12-22T04:09:03+00:00

Well, it's been over 24 hours and my home is quiet and warm with thenew furnace motor. I have replaced it yesterday and everything is wellso far. I hope it stays that way.Now another question. How does one adjust the dampers in a 2 storyhouse. I understand that in the winter I need to favor downstairs withthe air flow and in the summer the upstairs. I have two dampers tocontrol the left and right side of the house downstairs and a thirddamper to control up/down distribution. I have set the bottom two tobe almost all open and the up/down one to be almost closed, which woulddivert most of the air flow downstairs. After 24 hours with the newmotor and these settings the temperature is within 1 degree betweenupstairs and downstairs. I am happy, but what do I do in the summer?Just the opposite? I noticed when installing the motor that theheating wire went to the high speed and the cooling wire went to theslow speed on the old motor. I wired the new motor the same way, butam wondering why is the cooling slower?Thanks as usual, love the forum!Vladimir

Dec 22, 2005 22 Replies

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mm 20 years ago

How does this apply to auto heaters?

You're the first person I've seen mention that one can get iiuyouc, almost the same result with lower velocity and higher temp.

I like to put my car fan on one of the lower two speeds, because it makes too much noise in the higher two.

I figure that at lower speeds, the air spends more time in the heater core, and gets hotter, so that makes up for the fact that there is less hot air.

Am I right, and do you have a guess about how much heat speed 2 puts out compared to speed 3? It's a Chrysler at the moment.

Remove NOPSAM to email me. Please let me know if you have posted also.

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trader4 20 years ago

"I figure that at lower speeds, the air spends more time in the heater core, and gets hotter, so that makes up for the fact that there is less hot air. "

Yes, and no. Yes the air gets hotter at slower velocities. And no it doesn't make up for it. While the air coming out will be significantly hotter, you still get the most heat by having the max blower speed. Max blower speed forces more cold air into the heater which extracts more heat from the heater core.

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Edwin Pawlowski 20 years ago

Any auto with automatic heat starts the blower on low speed when the water hits about 110 degrees. This gets heat into the car as soon as possible, but at lower volumes. On mine, it steps up again at about 125 and again at about 150.

In any case, there is only so much heat available at a given temperature of the heating coil. Lower speeds give a higher relative air temperature due to the increased residence time, but overall heat output would be less than the optimal combination of coil temperature and air flow.

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