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  1. #41
    Well, as part of the electrical "check-up" I have been doing I took amp readings at various times on various circuits and have been balancing them out between phases to offer a more balanced load to the electrical... You could tell it was originally done based on the original design, but with the rec-room changes and other things being changed throughout the years it wasn't kept up and re-balanced until I did it...

    Well, part of that discovery was finding out the furnace blower (which we run 24/7/365 for air quality) was sucking down 11amps continuously. In looking at things I noticed the motor was original from 1989 and was rated at 9.6 amps. It is also a shaded-pole design that is amazingly inefficient (best source I could find said the most efficient shaded-pole designs could achieve 32% efficiency, with most falling into a 28-30% range). They are so inefficient that today nothing bigger than 1/6hp is ever made shaded-pole. This is a 1/3hp, 1050rpm, 4 speed 48-frame blower motor. In looking up a replacement, AOSmith (now Century motor) makes a drop-in PSC motor with an internal capacitor. It is rated at 5.7amps with a 6.0amp max draw, 4-speeds, etc, with a 60-65% efficiency (found conflicting sources for that one). So I had one shipped, pulled out the old blower and after a short time modifying gear puller arms and coming up with a set of shims to use as grab arms, I pulled the blower wheel off the original motor, got it all apart, cleaned it all up, and got it all back together.

    The result is much stronger air coming out of the registers, and it is only drawing 5.0-5.1 amps while running (that reading was taken at the panel 15 minutes after it was running, I will have to recheck it tomorrow). So I am saving about $70-80/mo already with the new motor compared to the old one.

    I also considered a ECM motor replacement for ultimate efficiency, especially considering they make a really nice one (the Evergreen IM) that would be a drop-in, but alas I already had the direct-model replacement on the way by the time I saw it. Since that uses a control-signal from the thermostat controls to control the motor speed, it sparked an idea. The way my current setup is done is that when you let the blower auto-control by the furnace it runs at high-speed for cooling, medium-hi for heating and if you set the fan manually on it runs at high all the time (regardless of other settings). Well, I don't think for air circulation off of heat or cooling mode I need to run the blower at max speed, so I am building a circuit to manage the speeds. I will set it with a rotary switch to select what speed I want for air circulation (probably will be low or medium-low), and it will provide overrides based on the heating or cooling mode being activated. If cooling mode is active it will override the rotary switch and run it at high all the time for maximum air circulation. If heating is active it will use the rotary selection for circulation, but once heating is commanded it will shut off the blower all together and allow the furnace to control the blower for proper startup and running. That way I alleviate the problem I had in the past in regards to backdrafting down the flue (since with the blower off it won't be creating a suction in the area), and it will allow the plenum to come up to full temp and then turn on the blower the way the furnace was meant to operate (which will optimize perfomance and longevity). All around it takes care of all the issues I have, as well as save me the most in regards to running the blower at the proper speeds that are needed all the time.

    Oh, I am handling the cooling season/heating season changes by a "state" that is set when either the cooling mode or heating mode is commanded. Even in the event of a power failure, upon restart whichever mode is commanded first will set the current state. In spring/fall when you can have a flip-flop of states I don't think it is a big deal for the blower to run at varied speeds until it settles in, one way or the other.

  2. #42
    Grandpa Grocery Getter 2.0 wrath's Avatar
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    Why not put a separate blower in that uses a synchronous motor for continuous operation?
    Buy made in the United States. Otherwise your job might be next. Unless you already wear black shoes and a visor with golden arches on it to work in which case your fellow american has already failed you.

  3. #43
    Quote Originally Posted by wrath View Post
    Why not put a separate blower in that uses a synchronous motor for continuous operation?
    I don't know if that is possible without reducting the air handler. I know it would be the most energy efficient method, but since I have two main trunks that run off the central handler itself (one goes east and feeds the front room/dining room/front hall/main level bedroom, with another that goes west and handles the rest of the house and is 2x the size of the eastward one), I am not certain the best way to integrate one without a ton of rework.

    Honestly, I am doing the whole fan-controller because I don't want to mess what is currently there, just optimize it as much as possible. I mean, honestly, the air handler and everything was meant as a "backup" for heat and primarily setup for A/C... Hell the furnace was installed in '89 and never even used until '94... They used electric heat exclusively before then... The run to the master suite is the biggest duct (8") and they even modified how it ran initially. It initially was the first off the westward trunk, had 3 90-degree transitions right away, which they changed since they capped off that initial 8" 90-degree port and tapped in with a drop-down so it had a straight shot with only 1 90 off the main trunk, then 2 more 90s and then goes up to the cold (ie, unheated) storage area behind the master suite, it runs in insulated ducting to a in-wall run that is y-split on the far side of the room. Works great for cooling the master suite, sucks for heating it (takes forever to come up to temp, and even then is colder output than anywhere else in the house) and with the blower fan running constantly it just acts like a cooler since it is going through cold areas (unheated spaces, outside walls)... I have that turned down to about 1/4 for the winter months, thus using electric heat in the master suite, but I have it full open in the summer.

    All of that is why I believe that cooling was much more of a priority than heating for the ductwork. With the main suite damper full open all the time, like I did all last winter, I noticed that the main suite would still need ot have electric heat running to get it liveable and with all that cold air in it was basically pushing all the warm air from that room to help heat the rest of the house.

    For the sake of finishing off the rest of the utility area, if keeping that damper mostly closed works for winter (and it has been working great since the electric heat hasn't run no-where near as much as it did last year), I may re-duct that run back to using the initial 3 90s since that piping will sit up high enough for me to put in drop ceiling in that area. I will have to see how it is for the summer next year with cooling running like that. I don't liek the idea of adding in an in-duct blower motor for just that room, so if it works good enough with the 3 90s, great. If not I will just rehook back up the setup I have now. I have a funny feeling that the reducting they did was an attempt to get more heat into the master suite in the winter once they started using the furnace. And I will say, about the only thing we notice being cold is the walk-in closet that is part of the master suite. But, it is also ducted for heating/cooling so if the heat has kicked in recently enough it isn't bad at all in there, but on the downside, if it is at it's coldest point it is eye-opening being about 3-4 degrees colder than the room itself.

    And, yeah, I know, if I shut the air circulation blower off entirely and have the furnace only kick in the fan when it is heating or cooling it might just work good enough, but I like how stable the entire house is temperature wise with the blower running continuously (as well as the increased air quality since the wife is an asthmatic) and I do believe it helps make sure the lower level doesn't get too cold as well. I think the lower level would be quite a bit colder if the air wasn't circulating all the time, thus necessitating me to run the electric heat down there to compensate, so I view it has 6 of 1 a half dozen of another kind of scenario. The previous owners used the downstairs as a rec room, so if it wasn't used all the time (like it is now) maybe the priority wasn't the highest to keep it up to temp, thus they wouldn't have minded using the electric heat as needed in that area.

  4. #44
    After reading this I am glad I went into PT and not electrical.

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