T'stat clicks on/off rapidly causing the A/C compressor to turn on/off
HU-116970229
2 years ago
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wdccruise
2 years agolast modified: 2 years agomike_home
2 years agoRelated Discussions
outside unit won't turn on (miller heat pump)
Comments (4)I looked up your wiring diagram and it appears y and w need to be jumpered. im assuming this is because Y doesnt serve as first stage heat in heat pump mode like 99% of other thermostats do. im also assuming w isnt wired to the aux heat and only W2 is wired to aux heat. normally on a heat pump stat Y is used to engergize the contactor in both heating and cooling modes and the O terminal switches the reversing valve accordingly. i..e.. in cooling mode Y energizes bringing on the unit with O energized to switch the reversing valve to provide refrigerant flow for cooling. in heating mode Y energizes bringing on the unit with O de-energized to provide reverse refigerant flow for heating. your stat does need the jumper in order for W to bring on the unit in heating mode with W2 providing the signal for aux heat. the stats i usually work with have a W/W2 terminal that serves as first stage heat OR second stage depending on setup configuration or dip switch settings. im assuming W is only jumpered at the stat and isnt connected to the aux heat. if so this could work. I normally work with honeywell or totaline stats which are congfigurable without the need for jumpers. your stat is kind of a cheapo but if it serves its purpose more power to ya hehe. I'd (if i were you) call a different tech out and ask him to look at tracing the safeties. I would try to explain how to trace the control circuits but that task is best left to a qualified professional. good luck Here is a link that might be useful: Ritetemp 8050C stat wiring...See MoreA\C compressor stops; won't restart until system down for 5 min.
Comments (21)"The last time it acted up i checked and had the 24 volts coming from the thermostat to the board but no voltage from the board to the contactor which is what made me think a pressure switch may be locking the voltage out" I want to be clear about something... When you say "the board", do you mean the control board that sits inside your furnace\blower? If so, that's what I mean as well. That board does a lot of things (including the timed shut-off delay mentioned below) but as far as I know, all it does to turn the condenser unit on or off is sent 24 volts over two lines to the unit, specifically the contactor within the unit. There certainly may be more complicated control systems out there but that's the way traditional A\C systems were set up. In such systems, the control board has absolutely no idea of what any "pressure switch" inside the condenser unit is doing, no idea of whether you have no coolant in the lines, no idea of any sort of problem or situation that might exist within the condensing unit. When that control board wants to turn on the condenser unit, it simply sends 24 volts down those little wires. If you turn your thermostat down far enough to signal that you want the room cooler, the thermostat sends a signal to the control board in the furnace, which then turns the blower on by the coils, and then sends the 24 volts to the condensing unit. If in fact you have "no voltage from the board to the contactor" despite you adjusting the thermostat to start the cooling cycle, then your first concern would be to understand why the board or the wires from the board aren't working properly. If, on the other hand, you mean some sort of control board within the condenser unit itself, one that acts as a second brain (third if you count the thermostat) in the system and takes into account information from within the condenser such as high and low pressure readings before sending the 24 volts along to the contactor, then sure, you might well have an issue with that particular board or the pressure sensors or perhaps a whole bunch of things. Don't know. What I do know is that if you are indeed talking about this sort of internal control within the condenser itself and when you think it should be triggering the contactor but you can't detect any juice between the internal board and the contactor, then your problem isn't the contactor. The only way you can determine whether a contactor is bad is to send 24 volts to it. If you do that but the 220 volt lines within the unit aren't energized, then it's the contactor and indeed, because contactor issues can be all about carbon buildup on the contacts, you might have the symptoms you describe. But if the contactor isn't getting the 24 volts at all, you need to look for another answer. I strongly suggest that you turn this over to a repair tech given that you're no longer talking about replacing a $12 contactor in 15 minutes. Nick in Palm Springs...See MoreNew a/c but doesn't perform like other a/c systems
Comments (26)So yesterday buddy comes over to look over things with the a/c system and I think we've got things nailed down properly now. The superheat for the given ambient temperature and heat loading from the indoor coil was way off (5F) vs. the 14-15F that it was supposed to be so he had to remove some of the refrigerant (I was quite surprised how little he had to remove to get the superheat up) and we even went as far as measuring the furnace's CFM flow rating using a differential manometer. I'm pushing roughly 1000CFM across a 2 ton coil so which is a tad bit on the high side but my colleauge says it's a margin of safety for the a/c to not freeze over as we have relatively little humidity in the air would means that on the cooler days we wouldn't be heat loading the coil enough which could lead to freeze up. I personally would like to try running my furnace on the lowest speed to get the 855 CFM but I'm not sure how that will affect the superheat. Presumably I would imagine that if a system is charged properly using the superheat method for fixed orifice systems that blower speed shouldn't dramatically impact the superheat values to the point where they're completely out of whack. I would guess that superheat would rise but isn't that sort of a given? I mean hotter days for example would increase loading so therefore superheat should rise no? For the record the pressure reading on the manometer with the furnace on medium low with a 3M 1500 series filter installed has a -0.44 in wg static pressure difference. With no filter the static pressure diff changes to -0.55. Humidity was still somewhat of an issue yesterday night when it was raining but it was quite cool outside. I had to drop the tstat to 21C to force start the a/c on but after just 20 minutes the house was nice and dry and less stuffy. Just for the sake of my understanding does TXV technically do any better or worse job of temperature/humidity control over a fixed orifice system IF both systems were installed properly and charged to near perfection? I have a friend that is looking to install a/c and his contractor insists on having TXV and says that fixed orifice is evil and should never be used. I find that rather extreme to make a claim like that. I've tried to do my own research online and although it's a given that TXV is the way to go I think it has a lot to do with the fact that it will better protect the compressor from liquid flooding + it's more forgiving for techs that do an incorrect charge on the system - critical charge isn't nearly as important on a TXV system vs. fixed orifice. Thanks,...See MoreWrong t-stat settings
Comments (7)My installer is responsive. Unfortunatly they have been out here several time this year. Unfortunatly again each time is a different tech who changes things different from the last guy. They have swapped out a lot of parts, some fixed a leak in the coil and some which were not causing any real problems. When I ask the same questins to the different techs in many cases I get different answers. Anyway I'm losing confidence in them so I am looking for answers on my own so I can me more educated. I also found out that becasue the t-stat is wired the way it is that the emergency heat feature is bypassed and will not function. I have verified this to be true because when I turn on the emergency heat nothing happens....See MoreHU-116970229
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2 years agoElmer J Fudd
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2 years agolast modified: 2 years agoAustin Air Companie
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2 years agoElmer J Fudd
2 years agoAustin Air Companie
2 years agoCharles Ross Homes
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2 years agoElmer J Fudd
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2 years agoElmer J Fudd
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