System short cycling, not keeping up, very high electric bill, and extremely high head pressure.
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- Опубликовано: 19 авг 2021
- System was going out on high head pressure. I washed coils, and thought I was done, but head pressure kept climbing, and temp drop never got above 11 degrees. I eventually settled on replacing TXV
#hvac
#hvaclife
#txv
I found that the micros are charge sensitive. Same issues. Ended up removing 10 ounces and brought the pressure's to livable. Micros need to stay in autos not HVAC
I haven’t seen a TXV cause insanely high head pressure like that. Usually liquid line restrictions don’t allow for return gas to the compressor so there is actually nothing for the compressor to compress to cause head to continue to climb. I would deep clean that coil and ensure proper airflow from the condenser fan.
Before you go replacing anything, try cleaning the condenser coil from the inside out.Could be a cheap fix.
Good job Curtis.
Nice job and video like always
Remember when you have a micro channel condensing coil, you must blow the water out of the channels after cleaning because it will hold water inside the channels and cause super high head pressure.
Nice work
One of our technicians had the exact same unit with the exact same problem 2 years ago. He replaced the TXV and it still didn't work. I went out there and found the problem was actually the indoor coil (micro channel) was completely slammed. To look at it it didn't look that bad. But once I started back spraying it from the blower side down, you would not believe this stuff that come out of it. The plugged coil was dropping the low side pressure so much that the other technician just kept dumping gas into it trying to get the pressure up and it ended up being 3 lb overcharged. The key here is.... Both coils are micro channel. That system probably only holds 4 lb and a few ounces. When you're dealing with a system that has micro channel coils inside and out you have to think of the charge in ounces instead of pounds. A few ounces of refrigerant can make the same difference that a pound of refrigerant would make in a system with regular plate fin coils. I think you should try heavily cleaning both coils (especially the evaporator), remove the entire charge, vacuum the system and weigh the refrigerant back in according to the data plate. 😎👍
Appreciate the advice.
He didn’t know what subcooling was? NEVER. EVER. EVER. Charge by suction pressure. Rookie mistake. Your guy needs a lesson on checking charge 🤣
Sounds like a winner approach!
It sounds good to me what you say, because txv works off of suction pressure.
@@jeffreywhitlatch1409 No...they don't. Spring pressure and suction pressure close the valve. Bulb pressure opens the valve. Airflow issues causes your saturation temp to plummet so the TXV closes down due to the bulb pressure dropping, sometimes far enough that you will see a very low suction and high superheat at the outdoor unit. The superheat at the evaporator outlet, however, will be proper. Airflow issues show up in your subcooling. When your TXV closes down you stack liquid in the condenser and your subcooling will go up. When you dump charge in because your suction is low your subcooling will skyrocket. First rule of troubleshooting is make sure everything is clean.
I had one like that couple weeks ago but install crew had just installed a new coil
High subcooling is always an overcharge. I’ve never seen a high pressure switch fail closed before. That’s kind of crazy. If I find a unit running crazy high subcooling I immediately go into “Some dipshit misdiagnosed a bad TXV and charged by suction pressure” mode. I just did one a couple weeks ago. Unit was running a slightly low suction, 30 degrees of superheat, and 30 degrees of subcooling on a circuit that should run 10. We are slammed and I didn’t troubleshoot any further. Replaced the TXV, found the unit grossly overcharged, and upon disassembly, the push rod was 100% stuck in the TXV due to oil breakdown.
Replacing TXV and adjusting the charge repaired your issue?
@@edwardgarza5104 yes. Someone charged it by suction pressure because the rod in the TXV was bound from sludge. It will happen again though. I don’t go out of my way to clean the system up for customers who intentionally run their equipment until the condensers are completely impacted. New TXV, drier, and a fresh charge. Whatever shit is floating around in the system from oil breakdown is still in there. 🤷♂️
Good vid ...
Have you figured that out yet? 6 years old - could be one of those Copeland compressors oil with coagulant from 2014-2015 clogging up txv
Maybe I’m not following the piping close enough but did you put your liquid line temp clamp on the outlet side of the metering device?
I wish the micro channel commercial/residential packaged systems didn't have a condenser guard that way you could slap the coil and knock the water loose. Anyways, Rheem and their damn typical TXVs!
Good content. Could it be overcharged if your head pressure is too high. Clogged filter drier.???
Please explain what your doing and what delta t. condenser or evaporater.
TXV only lasted 6 years? Its an expensive part to replace...
Nice video thanks for posting! did you try shocking the TXV sensing bulb? I like to put it in ice water for 5 minutes and then in the palm of my hand for 3 minutes and see what that does to the pressures. On new TXV's i try to never completely front or back seat the adjuster, as that's just asking for it to stick in 10 years, IMHO.
No, I didn’t try that.
You should never need to front or back seat a TXV spring adjustment. If you do, the TXV is junk. Your rod is sticking due to oil breakdown or debris.
@@HVACGUY is it a rheem package air conditioner
@@jman0870 Right, that's true my intent was to say a TXV should never be left in front or back seat position, It will stick, and imho some TXVs ARE just straight up junk, more moving parts, I work on residential AC often so if practicable i switch to piston w manufacturer information
@@Falcon-eh8tq TXVs are incredibly reliable...I don't know where you got your information. The number one killer of TXVs is oil breakdown outside of installation errors. I don't know why you would ever set a TXV fully front or back seated. If you have to adjust one that far it needs replaced because it's stuck and you are effectively operating it as a piston or it is the completely wrong tonnage range/body type/powerhead type. Maybe you are still stuck in the time period where Copeland put a corrosion inhibitor in their compressors without telling anyone and it was gumming up TXVs?
Coil clean?
Do you charge for cleaning coils
You swinged the temp probes 19 times total.... lol
How did it get that high over 500 and not go out on high head pressure?? Yikes
Tell me about it. That was worrisome.
@@HVACGUY Well, if nothing else, a great pressure test for a micro channel coil. 700 psi though.. damn
410a high pressure switches are commonly set at 575-600, that’s how 😂 410a sucks.
6 years old ,it should still be under warranty?
Did you give the txv the old tap-a-roo
Can't wait for the video of the replacement.
🍺🍺🍺🥃🥃🍿🏌🏻♀️
Stay safe.
Retired (werk'n) keyboard super tech. Wear your safety glasses.
It was registered, so yes it is under warranty.
I was screaming at my monitor, "ICE!! ICE!!! Moisture in the system! Frozen ICE is inside the TXV"! SUCK it down and get that moisture out.
Oh well, since you replaced the TXV, you had to suck it down it anyway. Now they have a brand new TXV. Not a bad thing.
Too bad that HI-Pressure switch is shot. She won't short cycle now!!
I haven’t replaced TXV yet
Noncondensables thought did cross my mind.
Ice at those pressures..?
@@richardbartlett6932 YES! An ice dam can hold back over 25,000 psi. Each time the ice, inside the TXV, melts and reopens a pin hole for refrigerant flow, the temperature re-drops below freezing and a new ice dam re-plugs the hole.
@@richardbartlett6932 But, who knows, it could simply be F.O.D., (Foreign Object Dam), blocking the TXV's orifice hole. Or the TXV sensing bulb has leaked and is kaput. Or the TXV pintle is stuck closed from C.O.D. (Copeland Oil Crud). Who knows.
Why are you washing the coils backwards? Pushing that shit into the coil and helping at all.
TX filter clogged
Hope you found your knife!
No, it’s lost somewhere. But, I found an electrician hook knife made by Milwaukee at HomeDepot for $15. Good price, I’ll be trying it out.
When you come across a system with those symptoms, the FIRST thing you do is check and/or clean the coils.
#31 thumbs up
First 👍😎👍