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I am looking for suggestions before I call someone. I have an ancient janitrol central AC. It's a 2 ton, model CK24B or something like that. It's old and way undersized for the house. It mostly cools the downstairs which is 1400sq ft but has a couple ineffective registers upstairs which is another 600sq feet. I had quotes for a geothermal unit or another air source to be put in last year and they sized them at 3 tons. Anyways, it runs for 5 minutes and shuts off. I cleaned the coil, changed the filter, tried a different thermostat and verified the drain is clear. It had a new capacitor and hard start kit last year. The compressor and fans start normally, no dimming lights or tripping breakers so I don't think it's that. What else could it be? It's 95, humid and pissing me off. I know it needs to be replaced eventually but that's not going to happen right away. I would love to just DIY replace it and the A-coil but I don't have the license to handle R22.
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Jun 14, 2016 00:28
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Outdoor, I can't clean the indoor one easily. Now that the sun is off of it and the temperature has dropped to 85 degrees it's running normally again.
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Jun 14, 2016 00:46
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It definitely acts like a limit switch. I have a laser thermometer, is there anything I can check with that to narrow it down? The big tube going into the outside unit is the suction line, correct?
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Jun 14, 2016 01:20
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Will do. Thanks for the advice, I slammed a cheapie window unit from Walmart in the bedroom for tonight. It may be a couple days before I get back to this but I will.
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Jun 14, 2016 03:02
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I ordered a set of "Mastercool" digital gauges model 99661 today. Shipping takes a week but the deal was too good to pass up. Compatibility with about everything, vacuum sensor and a clamp thermocouple.
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Jun 14, 2016 16:52
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Ok, so the gauges I ordered did not come through and I borrowed a set from work.  It's about 85 degrees out, 71 inside. Unit was cutting in and out when I got home but stopped when temp dropped below 90. I noticed that if its above 90 and I run a window unit in the house it doesn't cut out.
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Jun 28, 2016 01:57
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The unit is labeled for R22. I haven't tampered with it since buying house in 2014. I did have the propane furnace replaced in January of 2015 but they did not touch the refrigerant. The readings remained constant for the 20 minutes I had the gauges hooked up. It was about 80-85 degrees out the entire time, the 90 was before I had a chance to go outside and hook up the gauges. When I purged the lines it did not smell of propane. I think it's still R22. I think I may have a weak compressor. Last summer it wasn't starting. It would crank 2-3 times and then stop. I could see the condensing unit shake when it tried to crank. I did not have a meter at home capable of reading capacitance so I threw a new cap and a 2 wire(Supco spp6e) hard start at it to see if it would go again, and it did. However, it's never held the temp set point and does not dehumidify very well according to nest thermostat.
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Jun 28, 2016 04:05
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Well I think I figured some of my issues out. The house is ca. 1900, so not designed for any sort of central heating/air. It's a typical hack job install, flex duct everywhere, goodman, leaks, and the previous owner improperly installed an outdoor wood burning furnace coil on the return side. This only makes the single 10" return even more inadequate. There is no way it's getting the proper amount of airflow. So someone added a return "register" in the basement, and it was open, which explains the humidity problem. The filter box is also inadequate and doesn't fit any commercially available filters. On the supply side, well, there are only a total of 10 registers. Only 8 work because the previous owner tied off the section of flex duct that goes upstairs and it collapsed and flows basically nothing. Add to that the fact there is no return upstairs and it's no wonder why it's always sweltering in the summer and freezing in the winter. Also, the pressure from tying it off has caused it to become disconnected from the trunk in crawl space. So yeah, leakage and all that. So I closed the basement return, and found that my digital caliper box was the correct size to plug most of the return leak around the filter. Immediately more cool air was coming out on the first floor. I let it run like that all night and no freeze up or cutout. I ordered a differential pressure manometer off amazon and I need to figure out exactly how much air this is flowing. I also need to open the metal around the A coil and get a model number and figure out what type of metering device is in use. Like everything else I touch it's a mess. Picture of the monstrosity. I had the furnace replaced in 2015. The new one has an ECM blower which compensates for some of my problems but not all. The makeup air connection needs to be installed as well. 
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Jun 29, 2016 17:32
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I am pretty sure that your R wire should be on Rh and not Rc. Edit: also my 2nd generation nest has worked fine for a long time without the c wire. rdb fucked around with this message at 16:39 on Jul 28, 2016 |
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Jul 28, 2016 16:34
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ExplodingSims posted:No, Rc is correct for cooling. My bad. I was thinking since he had both Auxiliary heat and emergency heat that it was a dual fuel type system. Although I don't know where you would put heat strips in a furnace.
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Jul 28, 2016 19:24
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So I finally broke down and had a local shop with a good reputation come in and fix my return and supply ductwork. They also replaced my old 2 ton goodman A/C with a 3 ton carrier heat pump that matches the newer carrier propane furnace I had installed 2 years ago. I may have them come back and drill another hole through the house for the furnace air supply, but to my knowledge it's never been hooked up that way. Before:  After:  Feels so good not having to worry about propane cost so much any more. I had the tank filled yesterday, 400 gallons at $1.47 a gallon, should last the whole year. My next purchase will probably be my own 1000 gallon tank. To add to the discussion, I live nearest to Evansville, Indiana. My REC currently charges $0.10516 per kWh. The heat pump has a COP of 2.64 @17F and 3.92 @47F. It's cheaper 100% of the time to run the heat pump the way things cost right now, although it won't keep up with the demand much below freezing.
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Jan 25, 2017 03:18
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So it turns out my Nest thermostat sucks balls with a dual fuel heat pump. I really need an ecobee3. The only thing a nest will do is switch between the two based on a outdoor lockout temp. It doesn't take into account how long temperature takes to rise or how far below the set point it is. Which is kinda funny because when I had it hooked up to the gas furnace and outdoor wood boiler it would, so the functionality is there just not enabled for all setups.
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Jan 26, 2017 23:12
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You may want to check with the leasing office before you put a window unit in. I had a roommate once that refused to put the AC below 85. And the thermostat was downstairs near where he sat while my bedroom was upstairs with west facing windows. Long story short, no window units allowed but portable ACs were ok.
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Mar 19, 2017 03:59
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angryrobots posted:So recently found out that my electric co-op is offering a $500 credit for installing a "dual-fuel" electric and gas hvac unit. The ones that are basically an electric heat pump, but instead of heat strips they have gas for backup heat/2nd stage. I dunno how new these are, but I've been out of the loop or uninformed about them until recently. I had a heat pump put on top of my propane furnace. Sort of the opposite of your situation but the same end result. It's probably saved 200 gallons of propane since it was installed in January. The house stays comfortable enough and the electric increase was only $30 a month or so. Well worth it. For reference house is 2000sq ft, early 1900s construction, no insulation. Normal usage was 600 gallons of propane per year.
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Apr 10, 2017 14:33
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Last one is a carbon monoxide hazard and should be fixed ASAP. And yeah it needs to be replaced. That pipe probably heats up too much for tape.
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Jul 21, 2021 02:00
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Both the hybrid systems I have owned run propane when it calls for defrost. Carrier and amana, although both newer. You hear the reversing valve and the furnace fires up and warm air still comes out without the meter spinning like crazy. The best crossover is somewhere around 35-38 for me personally. Whenever it gets to the point where it just feels like cold air coming out of the vents. Also as far as brands go they usually all have a copeland scroll compressor and the coils probably came out of the same Chinese factory. Its the warranty and installer that matters most. I hear of lots of problems with inverter driven compressors and infinitely variable furnace controls but thats just hearsay. Personally I just go with a good compromise between COP/SEER and cost. Not the most expensive unit but a couple notches up from the EPA minimum.
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Aug 1, 2021 22:38
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| # ¿ Apr 26, 2024 19:22 |
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B-Nasty posted:I think a 2 stage compressor, controlled by the thermo, is a nice sweet spot. The lower stage for higher COP heat when it can handle the load and better humidity control in AC mode. Thats exactly what I put in my new place. Its 16.5 Seer on one stage and 15.5 on the other. Cheap dual stage amana 4 ton with a 96% afue propane furnace for defrost and cold nights. It was $15k for that and all sheet metal ductwork on a new build. I think its about the sweet spot and more importantly gives options if propane or electric jumps in cost. My neighbor suggested geothermal and it would have run about $5k more, but I didn’t want the added complexity of the ground loop, circulating pump and liquid heat exchanger. I can replace fan motors, control boards, capacitors and contactors on my own, the geothermal stuff I would be hesitant to mess with.
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Aug 2, 2021 02:05
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