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whatsthis 04-01-2009 01:34 PM

Electric Furnace question
 
I had a new Electric Furnace put in last year. All has been well, except that a sequencer had to be replaced a few weeks ago. ANYWAY, I noticed today that although the furnace wasn't running (thermostatically controlled) there was a faint humming sound coming from the unit (Like that heard from a flourescent light) . When I isolated the furnace at the breaker, the hum stopped. My question is, should there be any draw when the furnace is not running ? This doesn't seem right to me :huh:. Any help would be apreciated! Thanks.

yuri 04-01-2009 02:10 PM

The 240 to 24 volt transformer inside it can hum and that is not a problem. Put your hand on the plenum and if it is hot then you may have a sequencer stuck ON. Count the revolutions on your electric meter. Then pull the disconnect for the furnace and check the meter again. If it slows down a lot then get it checked again or you may run up a huge bill.

whatsthis 04-01-2009 02:17 PM

Many thanks. The bill is a bit of a sore point at the moment, as we keep the temp at 68 from 6 - 11pm, 62 overnight and 64 during the day, but it rarely comes on during the day since we get a lot of sun and that really raises the house temp. and according to Hydro One we are using 300+ units a day , and with everything new (inc the furnace) and CFL bulbs, we can't figure out why this is so high! We are genuinely VERY careful with the electricity, and feel that we can't economise anymore (there are just 2 of us in the house) but are flumoxxed about this high usage, it almost feels like something is leeching the electric.

yuri 04-01-2009 02:24 PM

Manitoba Hydro does some limited free service for homeowners. Check with yours and see if they will check the furnace and panel if you talk nice to them. A stuck sequencer will run 5000 watts and that is a lot of juice. You don't have a grow op next door ??:huh:

whatsthis 04-01-2009 02:45 PM

:eek: Grow Op?!?!?! Oh I hope not! Mind you, you'd think it with the way things are going! My F in Law was a spark, and has one of those gadgets (don't know the technical term) that loosely clamps around a wire and tells you what the load is on it. If I was to put that on the main (actually the only) cable (Big red one!) would that show if there is a unnescessary drain on the furnace?

yuri 04-01-2009 03:34 PM

It is called an amprobe. The furnace should be 240 volts and have 2 hot 120 volt lines. You would have to carefully open the cover and check each of the big wires coming in without electrocuting yourself. BEWARE the main fuse/breaker on most electric furnaces is 100 amps or more so you would be toast if you touched the main line. Each element draws about 20 amps so if one is stuck on you would see that. If the motor is off you should have little/no draw. How old is your house and do you have any other continuos running fans/HRV/exhaust fans. DO NOT go into the main panel and start checking things, next stop is the Nuclear plant or generating station!

kenmac 04-01-2009 03:35 PM

Quote:

Originally Posted by whatsthis (Post 253508)
My F in Law was a spark, and has one of those gadgets (don't know the technical term) that loosely clamps around a wire and tells you what the load is on it.



That would be an Amp meter


OOps yuri beat me to the keys

yuri 04-01-2009 03:42 PM

http://www.amprobe.com/cgi-bin/pdc/p...main&type=elec

Wonder if they still make the good ole black one with swing needle. These new ones are too hard to read for this ole buzzard/me:wheelchair:

Actually I have a nice true RMS MA line unit with large numbers.

kenmac 04-01-2009 03:48 PM

Quote:

Originally Posted by yuri (Post 253533)
http://www.amprobe.com/cgi-bin/pdc/p...main&type=elec

Wonder if they still make the good ole black one with swing needle. These new ones are too hard to read for this ole buzzard/me:wheelchair:

Actually I have a nice true RMS MA line unit with large numbers.


I had 1 laying around for a while.. Don't know if I still have it or not.. Doubt they still make them ,, Seems everything is digital now days.. The thing about digital it is what it says. No having to read between the marks

whatsthis 04-02-2009 07:42 AM

"How old is your house and do you have any other continuos running fans/HRV/exhaust fans. DO NOT go into the main panel and start checking things, next stop is the Nuclear plant or generating station!"

Oh I'm not going near anthying that isn't well covered and insulated, believe me!:yes: The house is about 18yrs old, there is no continuous items running (bar fridge etc.) The Furnace itself is new,(about 6 mths now) but we had trouble with it a few weeks back and had to have a sequencer replaced. It was running for ages on the low speed and not kicking up to high. Anyways, we had a new one installed and everything has been fine since then, but I was wondering if during this period (say about 2 -3 weeks til the part was replaced) could the furnace have been soaking up the electric? Just a thought!

yuri 04-02-2009 07:55 AM

Could be. The fan running all the time can cost up to $1 a day to run. If they don't read the meter every month (estimate one month) that could change your bill when the true reading occurs.

whatsthis 04-02-2009 08:21 AM

Thanks for all your help Yuri, just one thing more I'd like your opinion on! Talking of the fan running a lot..... Our furnace has a "mild weather" setting where I think only half the elements actually heat. Now heres the question! Which do you think is most economic
1. Full power for a short (relative) time to bring temp up to desired level
or
2. "Mild" setting where the fan runs longer on low heat (1/2 power)?
I've been trying to come to a conclusion on this and I can't so I'd really be interested in opinions or actual facts on this thinking!:online2long: Thanks again!

yuri 04-02-2009 08:59 AM

The mild setting may be more even/comfortable heat but at a cost. The average fan motor draws about 360 watts which is 1/3 kw x your elec rate ie: 10 c/kwh hour to give you the cost. Don't forget to add GST etc. I believe the mild setting is better for mobile homes as the older ones were poorly insulated so a longer run time is more comfortable. The furnace does not cost more to run on either cycle except for the fan.

whatsthis 04-02-2009 10:58 AM

Again Yuri, many thanks for your info! Was trying to work out the logic of the whole thing. Seems to me that a short, intense "burn time" would be more economic than the furnace just droning on for hours on end at a low setting, but wasn't sure!

beenthere 04-02-2009 12:41 PM

That short run tme, may cost more.
Depends on how hot it heats the air. And where the duct work is located.

If the duct is located in an unconditioned space. You lose more heat, the hotter the air is.


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