Do AC Blowers Take Breaks?

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I turned on my AC few hours ago and set to blower to ON, as opposed to AUTO. The temp hasn't reached the set point yet, so the AC has been running since I turned it on.
I was down in the basement doing some stuff (unrelated to the AC) when the blower stopped. Curious, I went upstairs to check the thermostat and it was calling for AC and the blower was still set to ON.
I went back downstairs and after about 20 seconds the blower came back on. I don't think it was off for more than a minute. This is the second season with the AC and I don't recall this happening before, but since it was off for less than a minute, who knows?
Any thoughts?
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DerbyDad03 wrote:

Blower motor may have a thermal protection device (in the windings). If that is tripping (and then resetting after cooling off), it's not a good sign.
The motor may need lube or the blower may be overloaded from excess static pressure or running at too high a speed. Have a peek at the filters too.
Jim
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It _may_ not be a good sign. Depends on what the controller thinks it's doing.

Blower motors consume _less_ power when their flow is restricted, and generally run cooler. They consume more power the more air they move.
I built an air cleaner system. It was a 1/2HP blower motor in a wooden box with three stages of 16"x20" filters (1", 2" and 4" thick). The blower was originally part of a forced-air cooling system for a computer or some such that _needed_ the flow restriction of ducting to operate properly. It would operate for about 20 minutes then shut down for 5 minutes because the motor overheated. Putting a flow restricter that blocked about 1/3 of the inlet of the blower solved the problem completely.
So, that's not it.
It'd be a good idea to wait for this to happen again, and put your hand on the motor casing to see how warm it gets. If it's the thermal trip, I'd expect the motor casing to be very hot when it trips. The motor got extremely hot in my air cleaner until I thought to obstruct air flow. Now it runs quite cool.
If it's a thermal trip, it's more likely to be a stiff bearing somewhere rather than anything to do with air flow (because they were engineered together, and should be just fine). May need lubrication.
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
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Speedy Jim wrote:

If thermal protection is tripped, it'll take way more than a minute to cool off and reset. Checked filter?
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On Sat, 07 Jul 2007 16:55:43 -0700, DerbyDad03 wrote:

Thermal protect built into the motor comes to mind but less than a minute seems too quick for it to cool down and reset. Keep an eye on it because no, blowers do not take breaks especially with the fan set to "on".
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wrote:

In the summer of 1980, I was working in a place that did injection molding (some very hot machines). The big fans kept stopping and starting. I seem to remember them being off for less than a minute.
--
Mark Lloyd
http://notstupid.laughingsquid.com
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- In the summer of 1980, I was working in a place that did injection - molding (some very hot machines). The big fans kept stopping and - starting. I seem to remember them being off for less than a minute.
Ah, that explains it! When I said "I was down in the basement doing some stuff", it just happened to be injection molding that I was doing! So, if I stop using this machine, my AC blower will stay on?
http://www.elitemachinerysystems.com/images/prod_images/1181753957-3000Clamp2.jpg
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http://www.elitemachinerysystems.com/images/prod_images/1181753957-3000Clamp2.jpg
Must be a very deep basement for all your equipment.
It is also possible the power company had a drop in voltage that could cause that to happen too. Hard to track that down if it was momentary. If it keeps happening you may want to check the voltage with a good meter, after checking what others suggested, lube and filters.
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The ones that smoke take breaks often. <g>
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On Tue, 10 Jul 2007 07:50:43 -0500, kjpro wrote:

Well you have a point there :)
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wrote:

How many hours is "few"?
Just kidding. I don't care.

And be sure to buy my book _Injection Molding for Fun and Profit_ by MM.
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After you have checked what everyone has told you, then you may want to gave a call the company that installed the furnace and have it checked out.
You never know what they may find, a loose wire, a sticking relay or what ever since it sounds like the furnace is alittle over a year old.
-- Moe Jones HVAC Service Technician Energy Equalizers Inc. Houston, Texas www.EnergyEqualizers.com
turned on my AC few hours ago and set to blower to ON, as opposed to<BR>AUTO. The temp hasn't reached the set point yet, so the AC has been<BR>running since I turned it on.<BR><BR>I was down in the basement doing some stuff (unrelated to the AC) when<BR>the blower stopped. Curious, I went upstairs to check the thermostat<BR>and it was calling for AC and the blower was still set to ON.<BR><BR>I went back downstairs and after about 20 seconds the blower came back<BR>on. I don't think it was off for more than a minute. This is the<BR>second season with the AC and I don't recall this happening before,<BR>but since it was off for less than a minute, who knows?<BR><BR>Any thoughts?<BR></BLOCKQUOTE></BODY></HTML>
------=
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I have a question about my blower that might explain what is happening -
The furnace is a Ruud 90+ 2-stage unit. With the fan switch on the t- stat set to ON, the fan runs constantly at the low speed, but when the t-calls for cooling, many times (always?) the blower runs at high speed.
Is it possible that when the t-stat calls for high speed fan operation, it overrides the ON setting, turns the blower off for a few seconds (<30?) and then turns it back on at high speed? In other words, it doesn't go from low to high, it goes from low to off to high.
I may do some testing when I get home tonight, but I thought I'd throw the question out first.
Thanks!
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wrote:

Yes, the blower (can) operate at different speeds for different stat settings.
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stat -- settings
Thanks, but that's not what I asked.
What I asked was this:
If the blower was constantly running at low speed because the fan switch is set to ON, would it briefly shut off (i.e. stop for 20-30 seconds) before switching to high speed if the stat called for A/C and high speed blower operation?
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On Sat, 14 Jul 2007 21:55:53 -0700, DerbyDad03 wrote:

If the stat is calling for AC then no, the blower should not turn off even for 30 seconds.
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wrote:

You sure?
Ever had a board with a 30 second fan start delay? :-)
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On Sun, 15 Jul 2007 14:49:06 -0500, kjpro wrote:

No.
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wrote:

What brand of equipment? Got a model number?
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It's a Heat Controller Conquest 90 Max Model number GTUA75-E3A which I believe is made by RUUD.
Thanks!
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