Big Increase in Electrical Power for Electric Furnace

[UltraFusion]

Hello;

I have a confounding problem with my electrical power consumption at my cottage north of Toronto.

I completely close up the cottage for the winter, only leaving the electric furnace on in the basement, with the basement mounted thermostat set to its lowest setting (ie. about 40 oF).

The basement is very well insulated. Nothing else is on at the cottage over the winter and we do not use the place over the winter.

For the past many winters my electrical usage for the winter months ranges around 1250 KWH - however this last winter the consumption jumped to 3400 KWH - and I'm totally puzzled why...

FYI - for this past winter the weather was (a bit) less severe than previous yrs so I would have anticipated the consumption would be similar if not less.

Everything is the same this yr as in previous yrs. There is no add'l places (windows, doors etc) where heat c/b leaking out, and again no other power was left on, etc.

The thermostat is working properly. When I did go up to chk on the place a month or so ago the ambient temperature in the basement was actually what it is supposed to be (ie around 40%) - meaning the furnace didn't appear to be running more than it should (and boosting the temperature).

Also the furnace appears to be working normally - ie. blower fan etc is working properly...

The power utility will be chkg the meter, but my guess is they may not find or report any issue with it.

So what on earth could be causing my power usage to jump by a factor or almost 3 times?? - Considering the only "culprit" has to the electric furnace (or the meter!!) can anyone suggest what c/b misbehaving with it to cause this issue...?

Any and all comments and suggestions very gratefully welcome.

Cheers, Glen

 

[UltraFusion]

Have done some deep thinking on my problem - and have come to the thought that the problem may be the blower fan (ie. the motor itself or the control/switch being either faulty or intermittent)
It seems to me that if the fan wasn't coming on properly (not running at all, or running slowly or intermittently) when the thermostat called for heat, the furnace elements would heat up but the heat in the furnace wouldn't get efficiently distributed through the air ducting back to the thermostat location.
Therefore the furnace elements would need to run for a long time before enough heat "drifted" to the thermostat location to shut down the heating cycle.
This would obviously cause the electricity usage to spike.
Considering this may be the fundamental problem, the question becomes how to troubleshoot it...
If the fan motor etc has down right stopped working then it's pretty easy - but I suspect (but haven't yet been able to get back on location to verify) that the fan is working either inefficiently or may be intermittent.
If the fan is running slow then that s/b obvious by monitoring when the furnace runs (and and the fan doesn't)...
If the fan is intermittent I guess it will just take watching it over some hours or days to see what happens (and what is causing it)...
Another idea I have is to disconnect the heating elements and continue to cycle on (and off) the thermostat so that the furnace can "run" (ie blower fan) without chewing up a bunch of power - and that way really be able to monitor the fan operation...

Thanks for letting me think out loud...

Any ideas on other furnace failure possibilities or ideas on trouble shooting the fan issue are greatly appreciated.

Stay well...

 

[James]

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place near the thermostat for a week and then view the results, you might find that the thermostat is sticking on and the temperature in the room is going considerably higher than you are expecting.

 

[UltraFusion]

EL-USB-2 | USB Temperature And Humidity Data Logger | Lascar

Experience the EasyLog EL-USB-2 from Lascar Electronics, an innovative USB data logger for accurate, efficient temperature and humidity tracking.

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place near the thermostat for a week and then view the results, you might find that the thermostat is sticking on and the temperature in the room is going considerably higher than you are expecting.

Appreciate your comment. You got me thinking. I'm ordering an Eiltech GSP-6 Temperature Data Logger that can log 2 temperatures, so 'll put one sensor near the furnace and the other near the thermostat, and that way I'll be able to accurately access what's going on for any temp differentials etc...

 

[James]

different make but you have got what I was trying to achieve.
let us know what you find please.

 

[davesparks]

Start with the some things, check that nothing else has been left switched on by mistake.
Then do a rough check of the meter, run the furnace on full blast for a measured length of time noting the meter readings at the start and end of that period of time. From this you can use the rated power of the furnace to calculate roughly howany kWH should have been used and compare it to what the meter has recorded.

 

[UltraFusion]

Start with the some things, check that nothing else has been left switched on by mistake.
Then do a rough check of the meter, run the furnace on full blast for a measured length of time noting the meter readings at the start and end of that period of time. From this you can use the rated power of the furnace to calculate roughly howany kWH should have been used and compare it to what the meter has recorded.

Thanks again for the comment - should have mentioned that a few days ago "Hydro One" (our electricity provider) had a technician go out to my cottage and tested the meter with a couple of different load tests (we had a good phone chat while he was there) and he determined the meter accuracy was good - but as a double check I will run a test or two as you suggest...

 

[davesparks]

Thanks again for the comment - should have mentioned that a few days ago "Hydro One" (our electricity provider) had a technician go out to my cottage and tested the meter with a couple of different load tests (we had a good phone chat while he was there) and he determined the meter accuracy was good - but as a double check I will run a test or two as you suggest...

Don't expect the figure obtained by the above method to be precise, it will only give you a rough idea of whether the meter is a long way out or not.
I don't know exactly how your furnaces work in that country but it's highly likely that it won't be drawing its rated power for all of the time it is running.

 

[UltraFusion]

Don't expect the figure obtained by the above method to be precise, it will only give you a rough idea of whether the meter is a long way out or not.
I don't know exactly how your furnaces work in that country but it's highly likely that it won't be drawing its rated power for all of the time it is running.

Have done some extensive troubleshooting and there is definitely a problem with my furnace - in fact looks like 2 problems.
1) one (of 3 total) or more of the the sequencer solenoids are intermittent/faulty. The first sequencer in fact has a wobbly connection (and some signs of over heating) for the heater circuit and occasionally throws off a spark!! ...
2) Also the fan blower occasionally fails to start up -

FYI - after the furnace has been 'resting' for a while and you step up the thermostat the furnace will start running - sometimes all three sequencers will work and you get full heat and sometimes only the 2nd and 3rd ones will operate and you get 2/3 heat, but the fan blower motor starts and runs normally.

Now it gets interesting - when the furnace shuts down (after running properly) - and you try to restart it (or just the blower (in "summer" mode) within a few minutes the fan motor doesn't run. There is power to the motor and the motor gets warm but it doesn't spin... The elements heat up.
Now you shut down the furnace and wait say 15 mins and restart the fan motor and it behaves properly.
I deduce from this that fan motor (haven't looked closely at it yet) has a centrifugal starting mechanism and maybe it's sticking a bit and takes time to slide back into it's resting/starting position... I feel very confident at that.

Now the question (in addition to swapping out all the 3 sequencers) is how do I fix the fan motor? Will a little lube on the mechanism do the trick - I'm guessing it will help (in the short term) but what are the longer term reliability implications? Would thinks it's probably better to either replace the motor with a new one - or have it rebuilt...

Welcome any comments and advice..,
Stay well...

 

[James]

I think some pictures of controls and fan motor including name plate would be really usefull from this point forward.