Today the temperature is -20C (about 0F). My set point for heat is 70 and the thermostat is set on AUTO. The furnace is a 6 ton Water Furnace. The house temperate is at 69F. It has been running at stage 2 since last night at 69F never reaching the set point of 70F. My average daily use of electricity is 100 kws. I measured the air temperature from my ducts and it is at 90F. Is this normal that it cannot get to the set point of 70F and what are the consequences having the furnace run at stage two for so long?

Is this your first winter with the system? Where are you located?  Any trees around your house (just kidding)?  Based solely on your comments so far, everything may be fine. To be more confident, it would be best if you could go through the "Problem with your heat pump? Start here..." thread at the beginning of this forum and answer as many questions as you can.

Assuming everything is in order, long run times do not present a problem for the system. If the indoor temperature drops more, supplemental heat (if you have it) may come on depending on the thermostat settings and logic. Keep in mind that supplemental heat is usually more expensive than running the geothermal system, so let the geothermal system run until it can't maintain the setpoint within a few degrees of the thermostat setpoint. Long run times take some getting use to (one full heating season for us.)

At some point of outdoor temperature, wind, etc., the system will not be able to keep up, and the indoor temperature will continue to drop from the set point.  That's when supplemental heat (or auxiliary heat) should kick in.

Only way to know would be to delve deeper into the design. Do you have a auxiliary heat coil?
j

It is my first time so maybe that could be the issue. I'm up in mid western Ontario and by the way the furnace did slip into stage 1 as soon as I wrote to the forum., but only after 8 of more hours on stage two. I do have an auxiliary heating system. Sorry to have troubled you with this request.

No need to apologize. :-) Lots of people ask questions regarding operation, maintenance, concerns, problems, etc. I still ask occasional questions about our system or responses (like I'm about to do now.) Feel free to write in.

When it's cold outside, you may notice the system go from stage 1, to 2, to 1, and back to 2, etc, without stopping between stages. This can be normal too. It would be good to get loop temperature readings periodically, if nothing else.

Tonnage would help me judge whether 100 kWh / day is excessive - on first blush it seems not so bad.

Do what you can with the checklist and get back with us

It was just pointed out to me that Mike S has a 6 ton Waterfurnace...my bad. I recently switched to a laptop with a much smaller monitor than I've been used to and I've been occasionally missing details like that - time for a new big monitor!

A 6 ton WF in high gear with 30F EWT ( a guess based on it being -20C outside) will use 4.25 - 4.5 kW plus loop pump(s) Calling it 5 kW would mean 100 kWh in 20 hours.

Is the 100 kWh / day what the unit is using or the whole house? If it is whole house, then I wonder if power use is too LOW.

90F LAT is pretty good...is there another source of heat in play, say wood or gas?

Michel Starenky,

WaterFurnace is represented by a distributor in Ontario. The name of the distributor is Eden Energy Equipment. We would suggest contacting them at (800)665-3336, as they will be more than happy work with you and your contractor to find a resolution.

WaterFurnace International, Inc.