HVAC Blower Not Working (suddenly) - Ideas?

Yes, you’re ok, and that’s the only thing your thermostat ever does in cooling.

It makes to connections; R to G, and R to Y.

Voila! Cooling.

another, another thing…

Motors/ caps often fail in the way you’re experiencing----they will run, but have a really hard time starting.

If you can actually get the fan to run with a manual push you can do this:

  1. Put a [semi] permanent jumper from R to G at the furnace.

  2. Set your stat to cooling and the desired set point.

What will happen is this: The condenser will cycle on and off as needed to maintain the temp you set. The fan, however, will run continuously.

This is OK. It sounds like your fan will run, but has a hard time starting. If this is so, the jumper will have it run continuously. Healthy motors like that can run for years without being shut off. It’s also inexpensive: If that motor ran for 30 days, 24/7, it may raise your electreic bill $7-15. Maybe.

If the motor will run continuously after a manual push without tripping out----and you’re miserable----- this is a perfectly fine (and safe) temporary fix.

Thank you for your help! You’re a diety-send!
I can do the bypass (I have strippers, crimpers, switches, extra power cords), but:
As I am a slob, having the guts hanging out is not a problem - but will having the access panel open damage the blower long-term (now until noon)

Cap is 370V at 5uf, and, thanks for the warning, but I do know to short a cap before touching a lead.

For what it’s worth, this on-off cycles with the blower has, on rare occassion, started all by itslef - no hand job required - does that skewer the cap/motor probability?

You can run the furnace with the panel doors with little problem. A minor and a semi-major concern:

  1. Minor. The motor will draw more amps because it can get all the air it can handle. Will it cause the motor to over-amp? I doubt it.

  2. More serious. If this furnace is in the basement it will take it’s air from the path of least resistance; and that path might be your flue/chimney. IOW, it may draw air down the chimney and if you have a gas fired water heater flue gasses (read: carbon monoxide) may not ne allowed to draft/ leave through the chimney. Obviously, that means flue gasses are in your home.

A huge concern? No. But enough that it’s best to close just the panel in front of the blower if you’re able to.

I took a course in solar heating in undergraduate school. Sizing the heating system was based on a project called “The Arkansas Story House” designed by the local power company. At any rate, calculating the airflow to each room was based on the fan running continuously.

My guess is the cap. (but I wouldn’t be stunned by the motor)

They’re not available at Home Depot. You’ll need to find an HVAC supply house (that will sell to the public) or the internet.

If you can afford to wait, and want to PM me, I’ll mail you one.

I’d like to hear more about that. Can I simply Google “The Arkansas Story House”?

Apparently not.
Essentially we calculated the heat loss from each room of the house, Q = UA delta T.
Total heat loss determined the size of the HVAC. Some division of that determined how much went to each room. It was long enough ago that I impressed the head of the department by writing a FORTRAN program to do the calculations in my computer science class. It was a main frame in Fayetteville and we used punch cards. :slight_smile:

We were randomly assigned cities and obtained the heating degree days from a table. We calculated the cost of a loan to finance the solar heating and ran it against the cost of heating with oil for the duration of the loan.

I drew Fargo, North Dakota. Average Winter temperature, 20 F.

I designed by the book, and lost money. I double the size of the collector, and lost money out the ass. I halved the size of the original design and made money.

As I recall, the primary concerns of the Arkansas Story House were using 2" x 6" studs and 6" insulation, proper installation of the fiberglass insulation, i.e. stapling the edge to the outside of the studs rather than the inside, a true vapor barrier of plastic sheeting, exterior corners constructed with two studs instead of three, headers on windows and doorways of plywood rather than 2" x 6" that allowed for insulation and attics rather than flat roofs.
The fan ran continuously, the thermostat was in the return path to the fan and room vents were adjusted to reflect the calculations made for the volume of air each room should receive. The instructor and his father ran an HVAC company that successfully used the design for installations.

Well, THAT was interesting - I re-connected the stat wires to the circuit board, with a 24 ga jumper across R and G. When the stat turned on the condensor, it killed the fan. Jumper be damned, it killed it.
I’m not ready to pull the cap (my back is killing me) - this is an oval design but I have no idea what the terminals look like - are they all the same? ebay has several, most (if not all) seem to be 1/4" spade. Safe to assume that is what I’m looking for?
Thanks again!

Yes, they all have 1/4" spade terminals. One place you can buy HVAC hardware as a civilian is Graingers, if you have one near you. Their prices aren’t stellar but they are well stocked and carry a wide selection of equipment.

Graingers now sells to civilians? Last time I tried, my EIN wasn’t enpugh to convince them to sell me paint! (sign painter’s enamel, in case you’re wondering)

I could not get Grainger to sell HVAC equipment to me, an ordinary schmuck off the street.

Graniger’s policy is moot - first pplace I called will sell it. I didn’t ask for refrigerant - an EPA licemse os require to legally buy that suff.
Thanks again


That ain’t cool.

What? :confused: