Pennsylvania Aux heat kicking on with heat pump

Discussion in 'Maintenance and Troubleshooting' started by Kenstone, Nov 2, 2019.

  1. Kenstone

    Kenstone New Member

    Hi everyone, I just had a brand new Carrier Infinity series installed. The install was finished about three days ago. One thing I've noticed is that when I change the thermostat temp more than two degrees the Aux heat kicks in with the heat pump. In the settings there is an option to use "heatpump only" should I use this setting?

    The set up is a 3 ton unit for the first floor and a 2 ton split unit for the second floor. I have 3 wells at 300' each. This system has a desuperheater that is not active yet because our old heating system was oil. I still have about 100 gal of oil left so my old oil furnace is still heating our hot water but will eventually be taken out and hooking up the desuperheater. Would this be affecting the system to kick on that aux heat? or is that just standard if you attempt to change the temp higher than two degrees? Please let me know if you need anymore information.
  2. SShaw

    SShaw Active Member Forum Leader

    I don't have an Infinity, but that's typical behavior for heat pump thermostats. When you move the set point more than X degrees above the room temperature the thermostat will upstage to the next stage of heating. On WaterFurnace the default differentials between H1, H2, and H3 are 0.5 degrees. So, if you set the thermostat more than one degree above current temperature, the unit will go to second stage, etc. There should be a thermostat setting somewhere, where you can choose the differential. You could set it to a higher value. Sometimes this setting is hidden in the installer options.
  3. Kenstone

    Kenstone New Member

    Okay that makes sense, I will probably just change it in my settings to use only the heat pump. Should I have the company hook the desuperheater up now versus waiting to run out of oil? My only concern is that I have the 1 year warranty with my installer so maybe I should take full advantage of that year to ensure it was all hooked up properly and test the system. I have 10 year parts and Labor from Carrier but I'm sure that doesn't cover the install stuff.
  4. SShaw

    SShaw Active Member Forum Leader

    Setting to use heat pump only is an option, but depending upon the size of your heat pump relative to the house's heating load, you might not be able to meet the thermostat set point on the coldest days. If you connect the DSH now it will supply some of your hot water, so it will take longer to use the remaining oil. Not sure what water heater configuration you have now, but to properly utilize the DSH you will need to install an unpowered buffer tank before your water heater. If you need to replace the oil water heater when the oil runs out, this probably means if you hook up the DSH now, you will have to have them come back and re-do some plumbing when you replace the oil water heater.
  5. Kenstone

    Kenstone New Member

    They did an extra 300 feet of loop to ensure I have enough, so hopefully that pays off. As for the oil yes it is currently heating the hot water and the second floor hot water baseboard heat. The new split geo for the second floor is basically just running its fan to circulate air now. Yes when they come to switch everything over I will have a buffer tank and a Rheem marathon electric hot water heater for hot water. They already ran the plumbing its just a matter of moving the current buffer tank next to the new electric hot water heater and turning on the desuperheaters. The amount of oil i have left would probably last till January maybe February; however, I'm nervous that I'm not taking full advantage of testing the install for a full year especially the cold months. I did not pay for the oil, it was there when we bought the house so I wouldn't be loosing money.
  6. jlifton

    jlifton New Member

    If your buffer tank is metal, I would seriously consider having it upgraded to a Marathon tank before the install. My metal buffer tank lasted a little less than 8 years before it rusted out, almost flooding the basement. So if you're going to be in the house for awhile it would be worth the extra money for a fiberglass buffer tank. Just my 2 cents.
  7. gsmith22

    gsmith22 Active Member Forum Leader

    while I don't disagree that the Marathon tanks are nice, it is likely cheaper to have a well insulated metal tank and switch out the anode rod toward the end of the tank's warranty period. Companies have calculated how long it takes the anode rod to corrode and base their warranty period on that. Changing them out is relatively simple and the rods can be purchased online for like $40 to $50. You can effectively make any metal tank (water heater) last your lifetime if you change the anode rod every 5 to 10 years (interval based on how fast the rod corrodes).
  8. Kenstone

    Kenstone New Member

    My buffer tank is actually going to be a Triangle Tube Smart 50, its basically brand new from the previous hot water oil system. From what I've read they are very efficient so I will be using that for the buffer tank.

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