Hey all, first post.
I recently bought a house (8 months ago). It has a Nordyne 5 Ton split system heat pump with 30kW of backup heat (all electric). The home is newer, well insulated, with Insulated Concrete Form walls. Single story with finished/heated basement. I have about 1900 square feet upstairs and a little less (1700) downstairs all heated and cooled by this system. I also have a 30,000 BTU ventless propane fireplace in the living room upstairs.
Oh, and the house is located in the mountainous region of western/central Pennsylvania. I think we have something like 7000 heating/degree days. It's a colder climate, but not like Minnesota cold. My heat bills were pretty high this winter, even though we posted the mildest winter on record. I mean it was like spring temps all the way back in mid January. Crazy. When I bought the house, I was quoted an average electric bill of $150-175. Well, the cheapest summer bill we had was $160 which was in September and the highest about $214. Then fall/winter hit. $250, 300, 300, 350, 400, 200. That's Oct-Mar bills. Now if we would have had a *real* central PA winter I would have been thrilled with those prices. However, it was very, very, mild and I expected to do better (at least as good as that 150-175 average they gave me).
So I did a little troubleshooting, and quickly found out that no matter what I did, the compressor/fan in the outdoor heat pump would not turn on. I waited for the reset time, reset the power, and the thermostat had no emergency heat setting so I knew it couldn't be that.
So I removed the cover on the electrical disconnect on the heat pump to see if the fuse had blown or breaker had tripped. It measured OK… but I noticed low voltage wiring in that box with e-tape on the wires and no wire nuts. At that point, my instincts said call a professional, so I did.
A few days later HVAC tech from a local reputable installer/repair place shows up (not the original installer). I show him what I found and he makes some concerning sounds "hmmm, oh boy, eeks." He says, let me look at this and I'll see what I can do. About an hour goes by and I hear two voices in the basement. Well, turns out he calls his service manager to show him just how bad it is. I talk to the service manager, and he says, "Ryan, you might want to sit down for this."
First we talk about the wiring to the outdoor heat pump. Five splices, thermostat wire run in same conduit as 240V, heat pump not even wired to turn on! It was hardwired for cooling ONLY! Some of the wiring was just wrapped around the metal terminals (no wire terminators, crimped connectors or anything).
Next he showed me the return duct trunk. There was only one trunk, a 20x8 duct for the whole house. Based on what he calculated, it was 50-60% too small.
The new contractor I called in ended up fixing the thermostat wiring and adding additional 18x18 return ducting in the basement. They also replaced the indoor thermostat because it was the wrong kind. This increased the airflow through the unit, and enabled the outdoor unit to actually function as a heat pump.
Later I went over the installation manual like a hawk. According to the system spec from Nordyne, the three supply circuits should have a minimum ampacity of 59A, 50A, and 25A respectively. The installer used two runs of 8/3 (wg) for this. Red and black of run #1 fed circuit A, red and black of run #2 fed circuit B and the white wires from both runs fed circuit B. The outdoor unit was piggy backed off of circuit C inside of the air handler, by just wiring the 8/3 run from outside to the supply side of the circuit C breaker.
The new contractor didn't catch the #8 supply wiring, not that I blame them with everything else so out of wack. I'm not sure if it's up to code or not or even acceptable. The one table in the older Nordyne manual states #6, #8 and #10 for the three circuits if 75C rated wire is used. I believe at a minimum I should upgrade circuit A to #6 and wire the outdoor unit on its own circuit.
Also, the original installer blocked access to the filter door with the way he routed the return ducting, so he just cut a new hole in the back of the air handler for access to the filter. Boy is it a pain to remove that filter because of that.
Lastly, no outdoor thermostat was installed to force the unit to switch over in extreme temperatures so that needs added too.
Basically I think it was a total hack job of an install. I'm also looking into whether it needs a crankcase heater or other options that were probably not even thought about.