Carrier / Bryant HVAC System Issues

[Traderfjp]

Hi,

I have a Carrier heat pump with a gas Carrier furnace for backup. I think the unit is about 13 years old. I noticed that my outside condenser was starting to ice up. I figured that maybe I was looking at it before the defrost cycle. Today when I came home I noticed that the condenser outside was extremely iced up with the ice and frost about 3/4" thick on the outside of the unit. Surprisingly it was still making heat. I turned off the system and scraped off the outside frost. Then I turned on the AC to try to defrost the coil manually. I went outside to watch the condenser and I noticed that the the fan of the condenser turned on for about 5 seconds and then shut right off. I tried turning the unit on and then off again, and waiting but the condenser did the same thing. I'm wondering if it could be a relay issue or a defrost thermistor (which I think means the whole board has to be replaced). Not sure. but there isn't an options for turning on the defrost cycle manually. The furnace is a 58MVP, the condensing unit outside is a 38YDB. I had the unit checked last year and the refrigerant was at a normal level. And the unit is not throwing any codes. I did try to turn the heat pump back on for heat and no such luck but thankfully my furnace is working so I do have gas heat. Any help is appreciated. Not sure how to change profile info but I live in NC now not NY.

 

[Fitter30]

Pages 19-21 safe web site. DO NOT turn the ac on to defrost unless you want to buy a compressor and maybe more. With no fault lights on would have waited another 15-30 minutes just to see what would happen. In the manual find resistants for temp sensors, time settings dip switches and manual defrost contacts.
https://data2.manualslib.com/pdf5/1...?c7d46c1c861c7af941dbb5aab94fbb77&take=binary

 

[Sponsor]

 

[Traderfjp]

Thanks for taking the time to post. Interesting enough my system wouldn't allow me to run the system in AC mode. Maybe there is a lockout or something. I'm running my system on backup gas heat. Anyway, once the ice melted mostly off the condenser I put the heat pump on and the condenser made heat with no problem. I didn't like that the condenser still wasn't completely cleared of ice so I only ran it for 10 minutes. I have a service guy coming tomorrow to check it all out. From my research it could be low freon, bad airflow in the house, clogged drain tube, bad thermistor, bad sensor, etc. While he is working on my condenser is there anything I should have him replace the capacitor just to be safe?

 

[Fitter30]

Times for defrost are adjustable.

 

[Traderfjp]

I had a service guy out just to check the system out. He thought the defrost sensor was bad. He forced a defrost cycle and then left. He didn't have the part on his truck. Anyway, after he left I decided to flip the heat pump back on. It ran well and when I went outside to check out the condenser I noticed that the unit initiated a defrost cycle. So now I'm wondering if the heavy fog and extra cold temps just iced the condenser more than the defrost could handle. They are probably going to want 350.00 to replace a 25.00 part. I'm thinking that maybe I should just replace the main board, capacitor and sensor and keep the old parts are backup. It'll probably cost the same as just replacing the sensor which I'm not even sure I need. I may take your advice and try to change the defrost timing to be more agressive. Any advice is appreciated.

 

[Fitter30]

Page 20 of the manual if you did in fact looked at fault light and was no failures I'd see what happens for a few days. Sensors that go out of range generate a fault code. Both coil and ambient sensors can trigger defrost and without comparing resistance to temperature have no idea which could be at fault. Some sensors come in matched pairs.

 

[Traderfjp]

Page 20 of the manual if you did in fact looked at fault light and was no failures I'd see what happens for a few days. Sensors that go out of range generate a fault code. Both coil and ambient sensors can trigger defrost and without comparing resistance to temperature have no idea which could be at fault. Some sensors come in matched pairs.

Thanks again. I went out today and didn't see any codes. The unit is going into defrost mode as it should. We had a lot of fog and then freezing temps so that may have been the cause of the excessive ice build up. I didn't want to short anything out so I used hot water to defrost the unit the best I could. I also changed the defrost cycle to 60 min instead of 90. When I was out there the unit went into defrost mode. After about 5 minutes I felt the pipe that goes into the heat pump and it wasn't hot. I'm wondering if my unit has a different problem then the sensor that the repair guys diagnosed but honestly he didn't check my smart thermostat for setting, he didn't check line pressure or anything else. I thought I would run it like this for a while to see what happens.