Heating strips run all the time wether I turn them on or not.
tboone0307
| Posted in Energy, Heating & Insulation on
Ive just moved into a rental with a heating pump. I dont know the name/manufacturer of the pump but can get it easily. The previous renter had a SMUD energy analysis done because her bills, just for heating the place were around $300 a month. SMUD stated that the heating strips are running continuosly and this is a big part of the problem The heating company that contracts with the rental agency states this is normal for this type of unit. Is this true or is there something wrong. From what I can tell the unit is probably as old as the house which was built in the 80’s. Any feedback
Replies
Not to the best of my knowledge
The ones I've seen were controlled by the thermostat. The heat pumps on the Folks house that was built in the 70's, had a manual switch to enable them, but they were still called by the thermostat.
Continuous operation would seem to be a huge safety hazard.
thank you for the information and the reply
Heat pump.
Heat pumps system will call for the back up heat strips only when it cannot keep up with the demand load. Depending on the age and condition of the unit and the design outside air temperature the older one worked in heat paump mode down to about 32 degrees F. Newer ones can work at lower outside air temps.
Low refrigerant pressures can become an issue for them durring cold weather. Also a dirty condenser coil is as bad for a heat pump durring the heating cycle as it is for one in a cooling cycle.
I have heard the HVAC guys use that BS many times. It is a standard explanation because it is a PITA to trouble shoot, leak check and charge a unit in freezing weather.
That is the first thing that comes to my mind, but i have also seen the wrong T-stat installed or mis-wired on heat pumps.
Time to call a rebutable contractor, but first get the manufacture information off the unit and look up the specification on the web site. Some sites even have trouble shooting guids that can help point you in the right direction.
Basically, be an informed consumer. The more you know, the better your BS detector works when dealing with anyone.
also thank you for the information. a lot of what you are saying makes sense. I will get the make and model and look it up. Ill get all the information I can before this heating company comes back out.. Thanks again.
A heat pump thermostat (when in heat mode) is supposed to have two signals it sends to the heat pump. The first signal says "gimme heat", and the second signal says "gimme heat RIGHT NOW!". In the simplest thermostat designs there are simply two "real" thermostats inside, one set a degree or two llower than the other. So if the temp drops below the setting of the first thermostat then the heat pump should come on. If the temp drops below the setting of the second thermostat then the resistance strips should come on as well.
It of course happens that the "normal" way to test a heater is to come in, crank up the temp 5-10 degrees, and see if it comes on. When you do this with a heat pump the resistance strips will inevitably come on. So testing a heat pump requires a more subtle approach -- the thermostat must be inched up slowly, possibly over a period of several minutes, to see if just the heat pump comes on. (And some digital thermostats are probably designed to detect that you turned up the heat and automatically turn on the strips because they figure you want the temperature to change NOW!)
I'm guessing that many HVAC guys don't want to spend the time required to do a proper test, and likely there are many who've never actually seen the strips not operate because they know no other way. So they would have no idea whether the unit is working properly or not.
If you're somewhat technically inclined you should be able to find the "gimme heat NOW!" wire, either at the thermostat or at the heat pump, and disconnect it. This should stop the heating strips (if not, there's an electrical problem in the heat pump's air handler), and you should then be able to tell if the heat pump working alone can keep up with the heat demands of the structure. If the heat pump keeps up OK, but reconnecting the thermostat wire causes the strips to come on, then the thermostat is likely bad. If the heat pump can't keep up, and the outside temp is above 35 or so, then the heat pump is failing or is undersized. And if essentially no heat is detected from the heat pump with an outside temp above 45 then the heat pump is simply not working, even if it's making noise and drawing electricity.
Where are you located? You're generally right. Back up heat shouldn't routinely come on. Maybe you got the wrong stat? Maybe someone changed it at some point w/out getting the right type for heat pumps. Maybe you got other issues (e.g. clogged condenser coil or evap coil) as someone else pointed out.
You have good reason to be concerned. Get the landlord to have it looked at.