"Gable" whole house fan

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ritelec

Senior Member
Location
Jersey
Hello.

I visited a potential customer yesterday.

He has a whole house fan GABLE mounted. There are two, I believe it's called, pillow block bearings on it that the shaft of the fan blade goes threw (Fafnir size RS).. they are rubber and one is broken so the fan was all wacked out..

I removed the belt to the motor. The motor spins...... I was thinking about using a nut and bolt with large washers and a hose clamp to rescuer the bearing and get the blades turning...


However, I'm not feeling right with such a fix... it may last a day or year or five... but it's an older unit and I don't want to make any guarantees and the "wiring"of it.

It's a Delco motor... It's wired off an old bx wiring circuit in the attic of an old house.

I did some research and I think delco stopped making motors in the 70's so I'm thinking this motor is 45 or more years old... I also don't see "TP" on it.


I'm thinking about running a new circuit to a new fan.. All my research is drawing a blank...
It seams there are a slew of Ceiling mount whole house fans but I can't find Gable mount whole house fans...

Only gable mount ventilators.

I'm thinking to replace the whole fan with new, but, I can't locate them, and, the existing fan is 36" and with the housing is 40". There's a scuttle to get into the attic which is 30 1/4" square..... from corner to corner is about 40 inches... with the trim removed it should be over 40" but would still be questionable if I could get it up and in...

So maybe the 36" fan, or since the opening is 30" Maybe I should go for a 30" fan ?? Would 6" of blade make that much of a difference? And again that's if I can locate Gable Mount.


So I'm also looking into replacing the two bearings and motor and belt...

Should the info on this motor get be to a replacement or would I have to crawl back up there to take some measurements and check rotation again?

Is there anything I should be aware of as far as class or rate of rise, ambient this or code that??


What do you think... try to remount the broken bearing and walk away? Rebuild it by replacing the motor,bearings and belt? Replace the whole thing with a new circuit?

Also to mention... turns out this has been broken for several years, but when it was working, the cover to the scuttle hole would have to get slid over. There are no louvers in the second floor hall ceiling, it's a scuttle hole.
I'm thinking about installing louvers in the hole or laying it on top of the ceiling joists so that they could slide the louvers over in the summer or wood over in the winter. Do you think the suction would be enough to open the louver, or would a motorized louver be required (or no louver and let them move the wood back and forth and no louver??).

Any opinions, suggestions, comments, MUCH welcomed.

Thank you..
 

iwire

Moderator
Staff member
Location
Massachusetts
Unless the fan or housing are bent I would replace bearings

If you don't know of a bearing shop in your area Grainger's will have them. Maybe $15 each.

If the motor is shot replace that too. Again Grainger's will have a suitable replacement.
 

PetrosA

Senior Member
I'm with iWire on this, fix it, rebuild it, whatever. Even in it's sorry state it's probably still better than what you'd get new and it won't cost that much.

I'm pretty sure you can get louvers that will work with that fan's suction. It's going to depend somewhat on whether or not anyone added ridge vents or other attic vents over the years. If they did, passive louvers probably won't work.

I wish I had a nice big whole house fan...
 

mgookin

Senior Member
Location
Fort Myers, FL
Is the purpose of the fan(s) to ventilate the attic or to ventilate the home?

If those fans have been there 50+ years without any air connection to the building, they may just be there to ventilate the attic when that gets hot which should help keep the occupied space from getting as hot as it otherwise would.
 

Jraef

Moderator, OTD
Staff member
Location
San Francisco Bay Area, CA, USA
Occupation
Electrical Engineer
Is the purpose of the fan(s) to ventilate the attic or to ventilate the home?

If those fans have been there 50+ years without any air connection to the building, they may just be there to ventilate the attic when that gets hot which should help keep the occupied space from getting as hot as it otherwise would.
Yeah, I agree. A "whole house fan" usually means it sucks the air out of the living space, INTO the attic. A gable fan exhausts the attic heat to the outside. Putting in a smaller fan would just make it take a little longer, but if there are gravity fed shutters, having less pressure / flow may not allow them to open fully, so check that out.

So that entire pillow block made of rubber, it's called an HVAC pillow block, because you don't want the fan vibration transmitting into the house framing. You can also get what are called "silent pillow blocks", but they are not going to be AS silent as that one, and your customer may end up complaining. Those type had no lube fittings, they were "permanently lubricated" with "long lasting" grease. Still, they do not last forever and with that motor being a Delco, it's safe to say it's WAY past the life span of those bearings now. Bottom line, re-using them is just asking for trouble.

In a limited access place like that, I would tell the customer they only want to pay for this once and replace the bearings, belts, motor and wiring now in one swell foop. Fixing one component only is just going to mean another call out later.
 

ritelec

Senior Member
Location
Jersey
Thank you.

I checked all over the internet and can't find new table type whole house fans.

Amazing. Only the type that go in the second floor ceiling. Also went to lowes and Home Depot. Only ceiling. Also went to grainger. Only ceiling. What gives.

So. Of knowing the exact replacement as lathe frame size is not visible. At grainger I located a motor that fits two of the frames which is about 280. I'll try to track down the rubber pillow block bearings but standard steel were about 45. They make one for air handlers which are supposed to be quitter at 85 a piece. Belt is about 15

All together about 500 bucks. So I'll give them a number. If they go for it I'll figure out what's needed. 4 hours of free estimate is enough for now.

I am thinking about something though. If there's a fire. Should provisions be made to shut the fan off.

I've never seen such a thing (except for smoke duct detectors in commercial) but it kinda makes sense. Smoke detector somehow tied into a relay ???


Thanks all
 

ritelec

Senior Member
Location
Jersey
To add one more thing. The louvre in the ceiling.

If I lay it on the access hole I'm not sure it will open.

The fan is in the gabble about ten feet to the side of the opening

When the fan comes on I think the breeze will go as the crow flies ti the fan through the louvre and they will only crack open enough for the breeze to go through and not fully open as if the fan was straight up above it.

Thinking maybe motorized. Or a rope touted above with pulleys to the closet to open the hatch.

But again. Not getting too deep into figuring it out till I get the okay
 

GoldDigger

Moderator
Staff member
Location
Placerville, CA, USA
Occupation
Retired PV System Designer
The simple reason that most if not all current whole house fans are designed for mounting inside the attic over a ceiling louver is that it allows you to have normal passive ventilation in the attic space (soffit vents combined with roof or ridge vents.)
To get the best performance from a gable mounted fan you would have to seal or omit all of those normal roof vents.

FWIW, a ceiling mounted fan, which has the motor and pulleys on the exhaust side of the fan venture, can be mounted on a gable penetration by boxing out the wall so that there is room for the motor on the outside facing part of the fan. (That would then also require adequate weather protection in the form of louvers or other means. Those means would also improve the appearance of the gable from the outside.)
 

ritelec

Senior Member
Location
Jersey
Good info. Thank you.

We will see how it goes.

I guess if the fan were ceiling mount the exterior louvers could be left on the building andante they would open up.

Thing is. There is no space in the hall ceiling. The fan would have to go in the scuttle hole

I'm not sure if they added any roof or soffit vents since it's been or not been working. So hopefully it did something they were pleased with that they want again. ????

Thank you.
 

GrayHair

Senior Member
Location
Nashville, TN
Good memories of a whole house fan!

Good memories of a whole house fan!

I grew up with a whole house fan; until I was thirteen. Would love to have one now :D but I'll be gone by the time the trees could provide enough shade.
 

Buck Parrish

Senior Member
Location
NC & IN
I have both in my house. I have the whole house fan right above the louvers in the hall upstairs . It's controlled by a Rheostat in the hall.
Then I have the gable vent fans. I have one thermostat controlling both gable fans. I've got one gable fan blowing in and one blowing out.

The gable fans don't cost very much and they come with a thermostat.
 

gadfly56

Senior Member
Location
New Jersey
Occupation
Professional Engineer, Fire & Life Safety
Replace the Pillow Block

Replace the Pillow Block

Look here for a replacement bearing. Looks almost identical to your photo.
 
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