Vapor fire 100 excessive blower speed

[SmokyBriskets]

Have a Vapor Fire 100 up and running and was a bit surprised by how much airflow is being blasted out the registers, even in low speed the airflow is still pretty high. Has anyone used a motor speed controller to attenuate the blower speed (and the noise) and if so did you switch the motor on the blower and use a variable frequency drive? (not sure if the original motor that shipped on the blower allows for using a controller)

There's only 7 registers connected using 6 inch round pipe to a 12x8 main trunk in which the VF-100 is roughly in the center of -- that may have something to do with it...

 

[Micdrew]

There’s guys here that are running a variable speed blower that I believe speeds up/down depending on the air temp in the plenum, sounds like you may have some undersized ducting? That’s probably why the blower is loud? im not an HVAC guy so I could very well be wrong, I can’t remember what lamppas specs on duct sizing are 180 sq inches rings a bell, you could add a duct in the basement if you don’t already. Hopefully the guys that have more knowledge then me see this and help you out.

 

[brenndatomu]

There's only 7 registers connected using 6 inch round pipe to a 12x8 main trunk i

That's way small.
Are you sure that it is running on low speed? Wouldn't be that hard to hook to the wrong speed tap at the motor...the blue low speed wire should be hooked to the red wire from the motor.
Could try a higher MERV filter(s) to slow things down a little...I'd worry about restricting air flow too much and getting things too hot though too...especially in a power outage situation.

 

[SmokyBriskets]

Probably should have described the ducting a little more accurately. The furnace is roughly centered in the basement with a 12x8 duct attached to the front side of the plenum at the top/right. There's a 10x10 square opening in the top of the plenum, mostly centered, that connects to a different section of 12x8 duct. The plenum and ducting is all sealed up with some 3M foil tape rated up to 300F (4 registers on one section and the other has 3)

When adjusting the thermostat to a higher temperature the blower speed does increase so the red and black wires appear to be right. I never looked at where the motor wires attach to on the blower motor itself, is it possible that something isn't connected right with that?

No cold air return ducting, just taking air from close to the basement floor and leaving the basement door open. Still need to add a box to take air from higher up. Thinking of adding a low resistance washable electrostatic filter as a first stage filter and moving the filtration to cold air snorkel box which would free up the filter space in the blower box. What do you think about adding an axial fan to move air (maybe put it where the air filter normally goes?) might have to add flapper valves to the fan baffle so the original blower wouldn't over rev the fan.

 

[brenndatomu]

Have you checked your static pressure?

 

[SmokyBriskets]

Don't currently have a manometer will need to get one but I also don't have a method for measuring the air flow velocity.

 

[JRHAWK9]

I had to drastically slow my blower speed down in our place. It made a noticeable difference in how the furnace heats the house. House much prefers lower volume of "hotter" air vs high volume of "warm" air.

I just used an ICM head pressure controller to turn my blower into variable speed. Something similar to this one. Been using it now since around 2016 or so. I use an adjustable ohm-pot to skew the temp the controller thinks it's seeing to where it works best for me.

ICM ICM327HNC Head Pressure Control | eBay

Function High Temperature Bypass, Heat Pump Override and Adjustable Hard Start Timming and Motor Cutout Speed. Pressure Low, Cutoff and Liquid Slugging in Low Ambient Condition. Hard Start Timing (Sec.).

www.ebay.com

 

[JRHAWK9]

If the OP has more questions on my setup, he can read more about it -HERE-.

 

[brenndatomu]

What do you think about adding an axial fan to move air (maybe put it where the air filter normally goes?) might have to add flapper valves to the fan baffle so the original blower wouldn't over rev the fan.

I wouldn't...just asking for trouble.

was a bit surprised by how much airflow is being blasted out the registers, even in low speed the airflow is still pretty high.

So what's the problem, really? Noise?

The ICM 326 has its own built in power supply...saves a bit of wiring, and in some cases (furnace model dependent) loss of power on overtemp
Here's one...and its in your backyard @JRHAWK9

ICM ICM326HC Head Pressure Controls Heat Pump Bypass 120-240 VAC (loc:BH@) | eBay

Box shows wear from storage. Photo's are of the actual item for sale.

www.ebay.com

I can't remember all the differences in the models, but I think I've used a ICM 325 before too. (also Totaline P251-0083, and 0083H...neither have built in power supply though, but tend to be a lil cheaper than the ICM's...I've used both, they work fine)
This blower mod works well, very well, but when the furnace is hot and doing its thing, your blower will still be running 100% speed.
And just FYI, the controller tends to induce some hum into the blower at low speeds...not on every blower, but most...and depending on how your duct system is built, sometimes that carries though the ducts a lil bit...for us, the house has to be pretty quiet to hear it...no issue for us.

 

[JRHAWK9]

The ICM 326 has its own built in power supply...saves a bit of wiring, and in some cases (furnace model dependent) loss of power on overtemp
Here's one...and its in your backyard @JRHAWK9

ICM ICM326HC Head Pressure Controls Heat Pump Bypass 120-240 VAC (loc:BH@) | eBay

Box shows wear from storage. Photo's are of the actual item for sale.

www.ebay.com

interesting!

when the furnace is hot and doing its thing, your blower will still be running 100% speed.

I guess it depends on how one has it setup. Mine never sees even close to full 120V. I'm also running a ball bearing motor and have mine slowed w a y down.

And just FYI, the controller tends to induce some hum into the blower at low speeds.

yep, they tend to "talk" a little bit.

 

[JRHAWK9]

but when the furnace is hot and doing its thing, your blower will still be running 100% speed.

I guess it depends on how one has it setup. Mine never sees even close to full 120V. I'm also running a ball bearing motor and have mine slowed w a y down.

Follow up on what I stated above.

I just looked back at a previous PM when I metered my voltage being sent to the blower when running the furnace on full output during a cold snap back in Dec '22.

It was only seeing 72 VRMS............ So safe to say my motor never sees 80V....probably not even 75V. I stated in my message back then that the motor was still making the humming noise at that 72V as well. I know I also metered the voltage being sent to the blower at shutoff and I know it was low......IIRC, in the ~40V area. So essentially I'm speed controlling my blower from only ~40V to ~75V at ALL times.

 

[brenndatomu]

Follow up on what I stated above.

I just looked back at a previous PM when I metered my voltage being sent to the blower when running the furnace on full output during a cold snap back in Dec '22.

It was only seeing 72 VRMS............ So safe to say my motor never sees 80V....probably not even 75V. I stated in my message back then that the motor was still making the humming noise at that 72V as well. I know I also metered the voltage being sent to the blower at shutoff and I know it was low......IIRC, in the ~40V area. So essentially I'm speed controlling my blower from only ~40V to ~75V at ALL times.

Yeah, you are WAY lower than me...mine hits 120V for a while when hot.

 

[JRHAWK9]

Yeah, you are WAY lower than me...mine hits 120V for a while when hot.

yeah, I'm not sure why it works so well for me and why I don't see good results pushing a full 120V volume worth of air into the house. My supply temps drop WAY lower and it simply does not heat the house as well when I am pushing that much air through the Kuuma. Has to be the way the ducting is setup/sized in our place.