Lower voltage on one leg - Furnace blower?

[Beth Adams]

I've been having a "brown out" in one ends of my home every time the furnace blower motor runs (which is a lot in this frigid weather). (gas forced air)

Checked the voltage at the panel. One leg was 123, and the other 97.

So, if you had to take a first guess, would you suspect the blower fan motor of trying to die, or that there's a problem with the service?

One option is something I can have replaced easily, and the other requires calling the utility and praying I'm right (or they charge you a ton).

 

[Reach4]

Checked the voltage at the panel. One leg was 123, and the other 97.

I infer that your blower runs on 240 volts. Not all do.

I would check to make sure the voltage was low on one leg at the incoming feeders, or at least on the output of other breakers. Normally the adjacent breakers are on different legs.

Your next step is to either call the power company, or call an electrician. Electrician is the right way, but that is going to cost you even if the problem is with the electric company. On the other hand the odds are that you will need an electrician anyway.

 

[Sponsor]

 

[LLigetfa]

Checked the voltage at the panel. One leg was 123, and the other 97

There may be voltage drop on the one leg due to the load not being well balanced and the service feed too small. Better would be to read the amps used on each leg. Of course it could also be a bad connection to that leg.

You probably should get an electrician in if you cannot determine the cause of the voltage drop. Unless you have a paltry 60 amp service, a single load should not be able to pull down the voltage that much.

 

[Jadnashua]

If you feel comfortable doing this (it can be dangerous!), pull the cover off of your panel and at least visually inspect the input power connections. Again, don't do this if you're not familiar working with high current power - tighten the clamps on the input power. Then, remove the breaker for the furnace and inspect the bus bar for arcing or corrosion. Note, circuit breakers can and do wear out...if the voltage on the bus is fine, it could be the CB is bad - if the voltage on the bus is not good, it could be the main breaker. Make sure that the leads of the power cable going to the furnace are tight in the breaker and at the furnace.

If the voltage on that leg is low on ALL circuits, it's probably either the input connections (could be at the meter, too), or the main input to the panel.

Depending on where the problem is, it may be the utility company's problem, or yours. Do any of your neighbors have similar problems? If so, it tends to point to the utility.

 

[Mr. Mint]

I had a similar problem where the drop from the pole was not properly crimped to the section that runs down the wall to the meter. It was arcing and causing a lot of radio static and then one pole went open, i.e., half the house was without power. The fix was to cut the old crimp connectors off and install new ones. The guy from the power company had a battery operated power crimper.