Heil dual fuel system heatpumps stop at 45 F. ?????

[eric76b]

Hello all .. I just bought a house a year ago, it was built in 1999 that has a Heil dual fuel system. It is a two story house with two Heil heat pumps, and two Heil LP gas furnaces. I notice once the outside temps go below 45 F. it switches over to aux and the LP gas furnaces come on and take over. House has two Robert Shaw 9520 thermostats. My last gas bill was over $1000.00 bucks for a month use off of 500 gallon tank. We did have a cold month but there was days it was above 35 F. Maybe I would of saved some major bucks if it would use the heat pumps!! What can be done to make them work more at lower temps around 35 F.? Or is there something wrong with my system? Just trying to get some ideas on this to look for before I call a tech and spend more $$$$$$$$

Thanks

[Pascone10]

Theyre are controls switching over to command to the furnace. This can be done a couple different ways. Either way I would call a pro to evaluate your systems. That a lot of dough for 1 month. Maybe you have another issue that can be corrected. Have your bills always been like this? What changed?

[eric76b]

Yeah I will definately get a pro on this. I think maybe they can check the balance point and maybe change it. Or I need different thermostats. Had Amerigas do a leak check on gas lines and no leaks. I usually turn my furnaces down to 60 F. when I leave for work and run them at 65 to 67 F when I come home. Maybe my system has lost it's efficient ability.

Thanks

[BaldLoonie]

There should be an outdoor thermostat that can be turned colder for more HP use.

Of course if you want to stop using so much gas, leave the temp alone when you go to work when it is heat pump weather. Chances are, the stat brings on gas to warm the house back up chewing up your savings. If you leave the temp up, the heat pump comes on occasionally to maintain. Cheaper than using a bunch of LP.

[eric76b]

Thanks guys I looked at both heat pumps and the one for the upstairs has a honeywell thermostat and its set at about 32 to 35 F. So I ll test that today and see if it comes one at 35 F. The other had none but I went underneath the house and looked at the control board the furnace, heat pump, indoor stat conects to and it looks as if it has a temp settings on it. It is set at around 40F. So something to look at. I dont want to turn this into a diy thing but at least I can get some concept at what I'm looking at when the tech comes over this week. I hate being in the dark on things..

[heaterman]

What are the efficiency ratings of your LP furnaces?

[rihvactech1]

i would call a pro about this and make sher they know how to work on heat pumps. i would look for some one that has a (nate cert) in heat pumps. they can get a little trickey. you can also get in tuch with the compeny who maked your heat pump and see what the heat pumps is rated for in temps lower then 45 b/c it might have ben desind when it gos lower then 45 the heat pump can not keep up this is unlikly but is possble i run my mom and dads heat pump till it gets to 30 out then nat gas is more effichant
i know lp is like 5 bucks for a galon it is one of the more higer priced heat choices

[BaldLoonie]

Still think the big warmups causing the LP furnace to run are the culprit!

[eric76b]

my heat pumps are Heil High Efficiencey 5000 series
Furnaces are Heil DC90 High Efficiencey furnaces
Can these run at lower temps?

http://i53.photobucket.com/albums/g69/compclocker/heil/100_1912.jpg

http://i53.photobucket.com/albums/g69/compclocker/heil/100_1917.jpg

http://i53.photobucket.com/albums/g69/compclocker/heil/100_1909.jpg temp adjust little unit set at 35 F.

http://i53.photobucket.com/albums/g69/compclocker/heil/100_1919.jpg control board for the bigger heat pump and furnace with balance point set at 40 F it looks like.

[BaldLoonie]

Slowly set them lower until you reach the point you are no longer comfortable and they are running non stop. The heat pumps can take it. With electric backup, they never shut off and may be running well below zero in some areas.

[eric76b]

I still can't get a tech to come look at this. I tried setting the balance point to 30 F. on the heat pump for the downstairs, on the heat pump / furnace control board. Today it was 37 F. outside. Temperature in the house was 65 F. I set the thermostat to heat at 67 F. Soon as it came on it went to the gas furnace for heat ran until I saw the temps reach 67 F. Then the heat pump came on? Ran for a for minute or two until it squeezed out the temp to 68 F. Shouldnt the heat pump come on if temp is past 30 F.? Since I'm not an expert at this at all. I'm asuming that the duct sensors are sensing the ducts being cold and is using gas heat to get the temps up. Once the temps are good, then it uses the heat pump to final out the temps. But that's what it seems like it is doing. Or the system is just jacked up. I'm not sure. Any Ideas on this? :confused:

[carls]

Get the costs of both electric and your propane, calculate the cost of energy produced by the heatpump at its low temp rating and calculate the cost of energy produced by the LP and go from there to see what your changeover temp is. My electric is about .06/kw and gas is .85 per therm. for me thats about 10 degrees but I set mine at 20 for comfort reasons.

[beenthere]

I still can't get a tech to come look at this. I tried setting the balance point to 30 F. on the heat pump for the downstairs, on the heat pump / furnace control board. Today it was 37 F. outside. Temperature in the house was 65 F. I set the thermostat to heat at 67 F. Soon as it came on it went to the gas furnace for heat ran until I saw the temps reach 67 F. Then the heat pump came on? Ran for a for minute or two until it squeezed out the temp to 68 F. Shouldnt the heat pump come on if temp is past 30 F.? Since I'm not an expert at this at all. I'm asuming that the duct sensors are sensing the ducts being cold and is using gas heat to get the temps up. Once the temps are good, then it uses the heat pump to final out the temps. But that's what it seems like it is doing. Or the system is just jacked up. I'm not sure. Any Ideas on this? :confused:

Don't turn the stat up buy 2 degrees. So boards will automatically bring on the furnace when you do this. No matter what the switch over temp is set to.

[eric76b]

I'll keep an eye on this when I get back this evening from work and see if I can get this balance point set ok. Thank you. A willTech hopefully be here next week.

[eric76b]

Yep your right the heat pump ran at a one degree setting. Also on the Robert Shaw tstat it has 1, 2, 3, degree difference. It's set at one degree does that have anything to do with heat pump working any better?

Thank you

[beenthere]

Its probably a deadband/droop setting. Allows the temp to drop more before bringing on the heat.