Air conditioning trouble shooting
background: I are a handyman and am pretty good at figuring things out. I also have the Dewalt HVAC/R professional reference book that has troubleshooting suggestions. So I have done all the routine preventative maintenance on my units. I live in Central Florida in case location becomes a question.
Unit 1- Heatpump downstairs – Indoor coil Freezing up. I dont have anyway to check upstream and downstream pressure nor do I have the ability to check refrigerant level. but the book mentions outdoor check valve- I need a picture of what this is where it is and how to tell if it is stuck or not. Also mentions indoor expansion valve again where is it and how to tell if its defective or not. If someone could tell me if I have missed something also.
Unit 2- Heatpump upstairs – everything runs and the indoor coil starts to chill but temp never gets below 80 degrees. also outside where the relays are the magnetic switch makes a huge noise. I figure it needs to be replaced since the other units doesn’t make the noise. Magnetic switch switches off when the thermostat is changed to heat, so I am pretty confident it has something to do with the cooling cycle. I realize this could be low refrigerant causing both problems but am interesting in making sure its not something else before calling a service man.
to be clear, I appreciate the input given to me. I have cleaned inside and outside coils, made sure new filters are in and checked all wires and connections to make sure something didnt vibrate loose. The fans all work correctly and there are no fan belts. I have attached a picture of the noisy magnetic switch. The units are manufactured by Rheem, approx 20 years old. they service about 800 square feet each since I have one for up and one for down and my house is only 1600 sqft total.
Replies
#1 filter dirty
as I wrote all new filters and all fins and coils are clean.
With no gagues it's all a guess, but typically - low refrigerant will not freeze the the suction line all they way back to the condensing unit outside because the gas flashes back up to temp by the reaches the compressor. Usually low air flow will freeze the line set all the way back to the compressor.Where did you get that capacitor from? You should get the contactor at the same place, but as pointed out - make sure you get the same type of single pole device. The other hot leg feeds the windings in the compressor to keep the oil warm and the refrigerant from migrating.Curious - even if you get some gages and the unit is low, how are you going to charge it and where are you going to get the R-22 from ? I'm all for DIY, but on the sealed refrigerating system of HVACR, I say you call someone.
Curious - even if you get some gages and the unit is low, how are you going to charge it and where are you going to get the R-22 from ? I'm all for DIY, but on the sealed refrigerating system of HVACR, I say you call someone.
I am just trying to eliminate any possible switch replacement that I can do myself. If it does turn out to be refrigerant I will have to call someone. I will eventually get guages though because I start my hvac/r apprenticeship in the fall. Three years and I can take the Journeyman test. I just hate paying some schmo 75 to hook up his guages and 75 per hour to tell me its a relay and its fixed in half an hour.
it will freeze up for two reason. low on freon or no air flow, dirty filter. dirty filter cheap, thats why I mention it. now on heat during cold days the outside unit will freeze up. that is normal.
87656.9 in reply to 87656.7
it will freeze up for two reason. low on freon or no air flow, dirty filter. dirty filter cheap, thats why I mention it. now on heat during cold days the outside unit will freeze up. that is normal.
what about the check valves out side or the indoor expansion valve, are these something I can diagnose or check to make sure they are operating. If I am low on refrigerant does that mean leak?
What about the other unit that never reaches a cooling temp. the coils get really cold but the air temp out of the vents stays around 80 degrees. Also we like our AC thermostats set to 75 degrees which is about what the outside air temp is nowadays, cooler at night barely 80 as a high. Normally we leave the windows open but since Ive been messing with the AC we havent.
Had inside coil turn to iceberg.... turned out to be low on freon.
PJ
Everything will be okay in the end. If it's not okay, it's not the end.
the noisy magnetic switch is a "Definite Purpose " Contactor. my guess is Furnas ,maybe even SqD. dont bother trying to repair it after 20 years
they are relatively cheap, if you cant match with the same Mfr. any brand of "Definite Purpose" contactor with the same AMP rating and coil voltage will work,
BUT,
make a drawing for the terminal wiring too if you don't buy an exact replacement
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, wer ist jetzt der Idiot ?
That's a single pole contactor. They have double pole contactors which break both lines. The single one only break one line so you still have 120 volts probably going to a heater in the compressor. Just becarefull to test for voltage. A noisy contactor is only a noisy contactor. Doesn't hurt anything or affect the operation. Is it a sign of going to fail? I've seen noisy contactors noisy for years.
The unit freezing could be lack of freon but usually what happens, in a non-tx valve situation, instead of having a coil full of freon at X degrees you have a smaller amount of freon at a colder temp and as you have less freon the temp gets even colder but over a smaller area so what you end up with is a really cold lump in one small area.
Usually afrozen coil is not enough air flow. Check the blower fins and make sure it is clean. Maybe the fan speed is too low. Maybe they have put fido's bed over the return air. Maybe the heat registers are all closed. Maybe the room they are trying to cool is already to cool and there is not enough heat coming back to the coil to defrost it. Maybe the underside of the coil is plugged with dirt.
The one that isn't getting cool enough, other than a refrigerant leak I would check the outside unit. You say it's clean and the fan runs, how about shrubs too close so it can't breathe.
Roger
see the photos, no shrubs both fans run same speed the one that freezes and the one that dont. I made sure all fins inside and out were clean.
Sorry. The part where I said fins I meant the blades of the squirrel cage fan of the inside blower. Also did you check the backside of the inside coil for dirt. I'd like to hear how you did that messy job.
And, Brownbag was very correct in saying if it is heating mode the outside unit would of course ice up.
Ice ups are usually a simple fix............................once you find it. Keep looking.
roger
I removed the green housing (see pics) from the sides and used a hose, hose end sprayer with nozzel removed (works like a pressure washer very effective) and a wet dry vac. I guarantee inside and out the fins on the outside units are spotless, even the tight spots around the compressor. No shrubs nothing is blocking airflow and I get good airflow from the vents. All new filters. Used my air compressor to blow the dust off of the blowers fins.
So apart from what I have done it just may be not enough refrigerant? I am checking the defrost cycle now to see if it will cut off and defrost. I may also be paranoid I have attached another pic of the inside coil frosty maybe that will help. I wish someone could send me a diagram of what everything is so I could better understand the layout and what the parts are. I would even be willing to photo my units insides and let someone label them for me.
Also did you check the backside of the inside coil for dirt. I'd like to hear how you did that messy job
I have my 9 year old son crawl into the register box and vac the bottom of the fins, Not really but have thought about it.
Actually I have an AC company come out and remove them and clean them once a year ususally by end of May before summer really kicks in. I also religously change the filters I will be very surprised if it is that. Gonna call them out and see what they say. Will let yall know.
Last night I typed a huge detailed message to you but it went poof, soooooo this one is a lot shorter.
You gotta check underneath/inside that "A" coil for dirt. Tricky thing to do for a beginner. The system looks like a restrictor orifice type (non TX valve) (TX= thermal expansion valve)
Are you sure that frosted one is a heat pump and not just an a/c?
Because it is a non TX valve system I'll ask this question: has anyone added refrigerant lately? By adding freon, the lowside pressure rises and up to a point you can still be cold enough to frost the evaporator but have too much freon which floods the evaporator and could give you a frosted look. You can a have really cold frosted look or a not-so-cold frosted look.
If someone has added too much freon and it is a heatpump you wouldn't "notice" any problem even though it wouldn't be very efficient BUT you would notice a problem in a/c mode because either it would freeze up or things wouldn't get cool. Actually in both cases you would notice it wasn't cool but in heat mode the unit would cycle longer to maintain heat and you probably wouldn't notice that.
What you are learning now will last you a lifetime.
roger
what I did was I left the AC filter in place and used my compressed air nozzle to blow through, I didnt recieve any noticeablely large amounts of dust. I get them cleaned once a year usually at the beginning of June and am fanatical about keeping the filters changed usually every month. My money after much help from the forum is there is an issue with the regrigerant. Probably that scumbag tech that ripped me for 225 bucks for 1.45 hours, replacing a blower switch and hoseing off the outside of my outside fan housing. I actually cleaned it later. the guy probably leaked out refrigerant so Id have to call them back out again for more money. Sorry if I sound bitter.
this goes back to what I saaid couple months ago. Find a dealer that has thirt trucks. over thirty employees, Been in business since 1975. They will cost a little more but will stand behind their work, and will do it right, they live off reputation.
yes , they are both labeled as Heat Pump. and I can hear the valve switch when we toggle from ac to heat.