Jim, I sure don't know anything about heat pumps but it's my understanding that the outside unit is running for the heat, as well as the cooling, but that some valves reverse the refrigerant flow; i.e., instead of removing heat from the house and putting it outside, it's removing what heat there is outside and putting it inside.
Bird, yes that is true it does both - but I have an outside thermostat and have it set so that at 30 degrees and below only the furnace is working. The heat pump shouldn't be doing anything. As Pat as recommended, I've thought about bumping it back to about 35, but so far since I dropped it to 30 about 4 or 5 years ago, we've been happy. Just trying to get the bugs worked out of the new one. The old was great, never had any problems once we got the outside thermostat until the hail storm. We paid a couple of high electric bills this year because of the inefficiencies of the smashed coils and it couldn't keep up.
Thanks for the information, Jim. I'm just learning about my first heat pump and of course things are a bit different here, since we don't have weather as cold as you do and our house is total electric, too.
Geothermal.
jwstewar, It could be worse, the heat pump could be trying to cool and the furnace be trying to overcome it and heat. I have Three heat pumps, two with propane backup and one geothermal that of course doen't need backup. The geo unit is the only one I'm running for heat so far. The in-floor hydronics are heating the 1000sqft great room-kitchen-entry and the convection currents off the heated floors warm the loft and any upstairs rooms with their doors open. Once it gets below freezing for daytime temps I will probably have to turn on the other units when the spaces they handle are occupied. Meanwhile with below freezing nights and 50's in the day the second floor is only a few degrees cooler than the main floor, 76 and 72F respectively. So far so good. The basement however is slightly warmer than I want it and I have its thermostat shut off. I have to do some more insulating of exposed hot water bearing pipes to cut don't o this "accidental" heating.
Hope they sort out your heating situation before any equipment is damaged or fails leaving you in the cold.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
"I'm not from your planet, monkey boy!"
They showed back up Friday afternoon. The wife said he was here about 1 1/2 hours. I don't know how much of that time was finding the problem vs. fixing the problem - I know in the computer biz I can take 3 days to track a problem down and fix it in about 5 minutes. He just told her that "It should be fixed now." and left. He got the double running fixed, but now we are on to something else. When it is going to engage the furnace, it kicks the fan on for 5 - 10 seconds (don't know about the outside unit don't feel like getting out of bed to check it. [img]/forums/images/icons/laugh.gif[/img] ) and then the fan stops and you can hear the furnace preheating. Sounds like another call coming up.
The company has been around a long time, they were real nice and seemed like the did good work. We've had this problem. Mom & Dad also had them install a new Nat. Gas furnace and heat at about the same time they did ours. When it started getting cold Mom & Dad had no heat. They forgot to turn the gas back on. Me, thinking that still didn't sound quite right - they did have heat then though. I"m like it shouldn't be trying for the furnace as it is still 50 degrees. It turns out it was wired up wrong and wasn't using the heat pump until it probably got below 30. Not sure I would have them back to do another or not, not sure if these type of problems are the norm for the HVAC industry or not. [img]/forums/images/icons/confused.gif[/img]
Jim
I have a Rheem propane furnace that has a very loud fan that engages for 30 seconds prior to ignition of the burners.
This is supposed to clear any "residual" gas out of the burner chamber to prevent explosion. Once the furnace ignites, the first fan shuts down, furnace gets up to operating temp, & regular blower motor starts.
Marty
Is your experience "Norm for the HVAC industry..." Well Yes and No. There are a lot of folks out there in HVAC who really don't know and many of those don't know that they don't know. The typical HVAC installation is oversized for a few reasons: 1. They really don't know how to do good heat loss and or gain calculations to support an accurate estimate of heating and cooling loads very well (if at all) so they err on the side of PLENTY and 2. There is more profit in larger systems.
Unfortunately oversized systems are more costly to buy, maintain, and operate. They short cycle a lot and wear out prematurely, well beyond warranty but sooner than they should but that is OK with the HVAC guy since he gets to sell another unit.
The efficiency of Freon compressors starts out pretty low and improves during a run, achieving most of its ultimate efficiency value in 30-40 minutes or so. Grosly oversized units often don't run as long as 30 minutes before they knock the temp down and the thermostat shuts them down only to make another short run as soon as the space warms up and triggers the thermostat. This is the origin of multiple problems, 1. lots of short runs are harder on the equipment, 2. the unit never achieves good efficiency so it costs more to run it, 3. since it knocks the temp down so fast only a small percentage of the air volume goes past the evaporator coil for dehumidificatioin. Reduced dehumidificationi means more run cycles to achieve a lower room temp because wth poor dehumidificatioin you will set the thermostat lower to make the room feel comfortable. With good dehumidification you don't need as low of temps to feel good and the reduction of delta T (outside temp minus the inside temp) there is less heat transfer through the walls and windows (another small economy.) Dehumidification is a very important component of conditioning the air in the summer (unless you are in the desert.)
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
"I'm not from your planet, monkey boy!"
Well Pat, I sure wish I could find someone who knows this stuff like you do. We have to replace our central air conditioner (the heater inside is fine, but there is discussion about doing it as well) and I'm all for efficiency.
But I would rather go with what I am sure will work for me, which is basically what I have - but not broken.
Chris, be careful what you wish for...
How high up are you elevation wise in the foothills? What are your typica worst case wintertime overnight low temps. Not the absolutely lowest temp ever recorded there but the lowest overnight temps you would expect to experience for a few nights in a row? Do you know what is under you for the first couple hundred feet? Hopefully not a few inches of soil over solid rock down to the magma.
How rare and of what duration are your power outages. Do you expect to be involved in the increasingly severe and wide spread brown and blackouts?
Do you have or do you want to have any backup for electric heat, i.e. if you have a heat pump would you want some kind of backup for power outages?
Efficiency:
If you go propane, pay a bit extra and opt for higher combustiion
efficiency. Lean toward a fully condensing gas fired furnace. Do not consider a VENT FREE heater.
If you opt for a heat pump, pay a little extra and buy a higher SEER unit. A SEER of 12 (min) is now mandated. I bought Lennox units with SEER of 19.2 running R-410A refrigerant. These became available within the last 2-3 years. Don't know if there is anything better out there yet. My HVAC guy and I did the math and changed our initial design (multiple ground sourced units) to a single ground sourced unit and two air to air heat pumps. The ground sourced unit will have to last 20 years to break even with the Lennox air to air units. If my design didn't call for hot water I wouldn't have a ground sourced heat pump in my particular situation.
You need to find someone who can do the math rather than rely on hearsay or what worked for some good ole boy's neighbor's pastor's aunt.
If you are at all interested in hydronic heat, check into the RPA (Radiant Panel Association) web site where you will find knowledgeable professionals in design and installation.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
"I'm not from your planet, monkey boy!"
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