Do in-duct booster fans work

[makolber]

My experience is that the motors fail if they are used in ducts with hot air. The thermal protections cut out.

I would set the air handler blower in the furnace to a higher setting.

Mark

[trader_4]

e:

nfo.php/products_id/563

summer temps would never go under 76 77 degrees i talked to 4 hvac special ist they all said it would cost over 4000 dollars to fix the issue. well i decided to try something a little different i used a 10 centrifugal fan pum ping 1100cfm used an ribu1c which is just a relay powered of the thermausta t and just like that problem fixed my temps now hover at 68 plus the fan is whisper quiet. dont listen to these hvac people all they wanna sell you is an expensive piece of tin metal, my setup has been running for 2 years now no issues and also have installed it on 4 friends systems with no issues

otor-DB6GTP/202797339

-Fan-DB208/100080191

I took the measurements at the 4 registers that put out the air from the rectangular duct where the booster fan was installed, which is the only logical place to take them. No significant difference at all.

[trader_4]

If you have that option, in many cases you don't, particularly for cooling. The older blower motors used the highest speed for cooling to begin with. The newer ECM motors may have a higher speed setting, it's certainly worth checking. But even that may not help, because you're just moving the air around faster, not changing the relative proportions. Move enough air downstairs to get the thermostat to turn off and it still turns off, leaving the upstairs probably just as hot. What is really needed is to get less air downstairs, more upstairs. Shutting off some downstairs registers in areas that get cold first can help. You just don't want to cut down the airflow too much by closing too many.

A lot of this could be solved for little upfront cost when it was installed. What should work would be a dual stage compressor, an automatic damping system, and an additional thermostat for upstairs. If the lower level is cooling off and nearing the desired temp, the unit could switch to low stage and put most of the air upstairs. Doesn't seem like anyone does that though. More common and expensive solution is to use two furnace/AC systems. That brings it's own problems, because the second system winds up in the attic.

[Ashton Crusher]

Is it possible there were a lot of leaking joints in the ducts between where you put the blower and the outlets? I'm surprised it didn't work a lot better. Only other thing I can think of is that there is a really significant restriction somewhere in the duct system back of where you put the booster and it's just not going to let air thru.

[trader_4]

rote:

the summer temps would never go under 76 77 degrees i talked to 4 hvac spec ialist they all said it would cost over 4000 dollars to fix the issue. well i decided to try something a little different i used a 10 centrifugal fan pumping 1100cfm used an ribu1c which is just a relay powered of the thermau stat and just like that problem fixed my temps now hover at 68 plus the fan is whisper quiet. dont listen to these hvac people all they wanna sell you is an expensive piece of tin metal, my setup has been running for 2 years now no issues and also have installed it on 4 friends systems with no issue s

l-Motor-DB6GTP/202797339

ter-Fan-DB208/100080191

DB205/202797334

Not in the part I can see in the basement. After that, they go up to the second floor through walls.

I'm surprised it didn't

I think it's that the squirrel cage type probably don't work at all. Just to be clear, this is the type:

false

Only a small part of the blower extends into the duct and I was even wondering how effective it might be when I installed it because of the design. The fan type that go inside the round ducts seem more likely to work to me.

[shopgacct]

I too am considering a booster fan for the the ductwork to an addition to the house. I don't think I would want to use it all the time and will install a switch to turn it off. Will a deactivated fan impede airflow?

[trader_4]

Sure, anything like that in the airflow causes more resistance. I put in one of the squirrel cage type blowers, where you cut an opening in the bottom of a square duct and put it in. It extends part way into the duct. I was trying to get more airflow to the upstairs. I initially though it worked. But later I bought one of those air velocity meters to actually measure the air flow. No difference with and without it on.

[clare]

yes

[Richard]

replying to Christopher Nelson, Richard wrote: Before you add a booster fan, make sure your blower wheel is clean and set at the proper speed for A/C, also when you are in the heating mode, and your filter is clean. Cleaning the blower wheel is a necessity.

[Mickey]

Your reply is too late.  The OP and his 400+ gerbils died of heat stroke.