what a great video, this is how you do tuts online, show on how to troubleshoot the unit show how to find the problem, and show solutions, no steps skeep, great video...

Thank you. Some people way over-diagnose to arrive here, while others way over explain the process to the point you get lost in the diagnosis or explanation. Others under-explain the diagnosis because they are referencing knowledge in their head that they have and I don't. This hits right where I can understand it best. I have a 21 year old unit I'm not spending any more money on. I'm having it replaced. But that doesn't mean I don't want to solve the puzzle of what is wrong. I have an Amana with indoor and outdoor TXV. It seems to run fine in cool. But the outdoor unit trips off in heat. Sometimes it will run a cycle or two or a day or two in heat. Then the next time it turns on the outdoor unit will trip off after a few seconds or a few minutes. I know this from changing the contactor and changing the capacitor and trying again since it was cheap to try. I know it is impossible to know without having someone come out again to hook up some guages and diagnose, but I think the outdoor TXV is the problem. I would think if the bypass check valve were stuck or a pressure switch were bad it would cut out consistently. The only thing near consistent I've seen are the times it kicks on again after a successful few cycles and trips off in seconds. I saw it do that a few times consistently and thought well the contactor or capacitor might be about gone. When I realized it wasn't the problem I cut it off, put on the emergency heat and put in a service call. They sent a guy out to check it. When we put it on it ran fine and the pressures looked OK, and the electrical checked out OK. I explained it would eventually start tripping out again and he just said well it could be a lot of things, it might be the compressor going and it's pretty old to be spending much on fixing it, and I already had the latter part in my mind anyways. Does this sound like outdoor TXV to you? I am tempted to cut the stuff off the sensing bulb, have a look and re-wrap and attach it with fresh stuff.

@AIRMANHVAC

2 жыл бұрын

If it heats fine when it is working, I wouldn’t look at the txv as the culprit. Sounds like a pressure switch or maybe even the defrost board or defrost components if its old enough to have the relay/timer defrost set up. I would want to catch the issue or be ready when it happens with a volt meter and check my low voltage coming in on the Y circuit and see where it stops. Obviously it’s not getting to the contractor when you’re having this issue.

@DusterMtnEX

2 жыл бұрын

@@AIRMANHVAC Heat seems OK to me and the big line is hot to the touch. Yeah it's my luck it don't happen when a contractor is here. First guy I wasn't here, checked it out, checked the coils said they were clean. But said a spider family must have spent the summer under the cover and the contactor looked pretty burnt. So I OK'd that to be replaced. Then when it quit that night the next day I went and got a capacitor and did that myself. Then I called another company out and made sure I was here and it didn't trip then either. I think I would have to do the ugly thing of leaving it where it trips off and the backup eventually comes on until someone gets here. Yes, it has TXV's and a copeland scroll but still has the old style 30/60/90 defrost board. That is something I have replaced myself other places I've lived. I have also replaced the nice ones with the sensing bulb on a Rheem. But for the obvious failure to defrost. I hadn't considered the other electrical controls. The pressure switches look like the thread on a schrader type. As old as this thing is the parts may be cheap, like save it back in electricity by the time the new one gets put in. Thank you for responding and getting my wheels turning.

@DusterMtnEX

2 жыл бұрын

I couldn't sleep tonight so I decided to use the time to test it and get a better answer than "Heat seems ok to me". So I set the defrost to 30, cranked it up and started collecting temperatures. At 35F outside, 70F inside, the insulated line is running about 110F where it's uncovered before entering the air handler. Little line room temp. Return air is 70F, supply air coming out of the vents is 95F. Outside it starts frosting at the TXV and it spreads to the capillary lines, and then forms frost bands on the outdoor coil. But it doesn't get real bad of course because the timer is set to 30. It ran cycles, satisfied, then ran a long cycle and went into defrost. Switched back and kept going no problem. I read through the service manual and is says the high pressure control resets manually. So thinking that would mean it would lock out I thought I could used that to say OK low pressure. But it does not state what that procedure is. So I may be resetting it not even knowing by going to the thermostat and changing over to emergency heat. Then coming back later and testing again. I dunno. Looks like it's not going to trip out again until I am asleep or a few days from now. Who knows. I guess it could be an intermittent pressure switch. I haven't been able to find the parts either. It's old so I will have to call the tech and see if he can find and price them. Or maybe it could be a piece of metal flash finally fell of somewhere where it is not really circulating and not really lodging either, just occasionally finding it's way to a spot turned the right way to make a restriction. I had an old retired HVAC guy tell me he ran into this once where several techs had been called in on an intermittent problem. He said he pumped it down, opened it up on the inside and and a little odd shaped piece of trash fell out that had one flat side. Said he put it back together and it ran for years and they stayed a customer from then on. He guessed that little piece of trash was hanging out just kinda free-balling around and every once in a while it would get in just the right position while also being turned with the flat side the right direction to cause enough restriction to trip it off. I may not get to solve this puzzle before the new one is installed, which will bug me.

Thank you I love the content

Great job

I have seen the broken cap tube on outdoor units before. Especially Rheem.

By the way, very good video and love the beard.

I had come across this maybe once or twice in 15 years. Then found two in one week. One of them was a rub out on the line feeding the bulb on an old lennox. The other just age on an 03 r22 Trane. Weird stuff.

You did all that nice work but shocked you didnt change the heat side liquid line drier .

@AIRMANHVAC

Жыл бұрын

Rick, I’m shocked too. It happens.

@mikaelg5840

Жыл бұрын

Or purge with nitro during brazing

@robertmarshall8369

10 ай бұрын

what is a heat side liquid line drier?

@HVACRTECH-83

6 ай бұрын

​@@robertmarshall8369no such thing lol who knows

@DJV94022

4 ай бұрын

Thats because the lennox has it inside the condenser..so youll have to cut out the old one which is not ona very accesible spot ..install a bypass 3/8 copper tube. Braze it back up and go back inside the house to install it (florida) or near the ports if you dont care.

I had this happened to a Lennox rtu heatpump and it was the filter drier that was clogged.

12:32 - What challenges do you foresee by leaving the old filter drier? Also, I didn’t see your nitrogen tank during the braze (maybe it was hidden from camera view).

May I recommend you start purging with nitrogen while brazing to prevent oxidation, also replace your filter drier anytime you open up a system. Good work practice.

@AIRMANHVAC

Жыл бұрын

I recommend the same.

@zacharyreed45

6 ай бұрын

I dunno why, these recommendations always irritated me. Best practice, sure. Absolutely required, no. Here's my recommendation, installers quit cooking the TXV and bulb. It's either flooding, starving or hunting... weeeee

@HVACRTECH-83

6 ай бұрын

​@@zacharyreed45wit any system utilizing poe oil it is absolutely necessary to purge while brazing,as well as replace driers any time system is opened. If you're not doing it, you're doing it wrong. Period. I recommend doing it on all systems regardless anyways

If you hooked your high side hose up to the liquid line instead of the vapor line, it would allow you to check subcooling in either mode without having to move your temp clamp. I always like to see if i have sucooling before the txv or not. Tells you alot. The issue can be inside or on the way to the outdoor unit somewhere.

@AIRMANHVAC

5 ай бұрын

I have yet to see a manufacturer list a recommended subcooling in heat mode. All I have ever seen is a graph with the outdoor/indoor ambient with a correlating pressure for those temps. So, yes you can check the subcooling in heat mode but there are no guidelines offered by the manufacturer for comparison to show whether it is charged properly.

@HVACRTECH-83

5 ай бұрын

@AIRMANHVAC I havnt seen a recommended sc for heat mode either but you still want to check it in heat mode. If you have zero, that's a big problem, then again if you have 20 or more,that's also a problem. I guess it depends on what the symptoms are. If someone overcharged it and you have really high SC you're not going to have shit for a temp rise inside. If you have real low or none your just going to ice up outside super fast as well as have shit for temp rise inside. Idk I always check both sh and SC in both modes. Also the best way to see if it's the txv or not

How long was that line set my friend?

Can’t believe u didn’t change tht dryer 😮

Would a bad odu txv cause my hot vapor (suction line) pressure to go over 600psi (410a) in heating mode?

@AIRMANHVAC

Жыл бұрын

Possibly, I find it more common that the system is overcharged in those cases.

New split unit heat pump. Indoor coil has a orfice nd outside has txv. Unit cools perfect. On heat the head pressure climbs to 500 within minutes while suction stays the same at 100 psi. Properly charged. What’s the issue?

@AIRMANHVAC

Жыл бұрын

Dirty Filters - Dirty evap coil - Inadequate air flow across the evap coil or it’s overcharged. I’d weigh the refrigerant out and compare that to the factory weigh in.

@nickelgracing9313

Жыл бұрын

@@AIRMANHVAC it’s all new. Factory charged.

A liquid line restriction has the same symptoms as a restricted TXV do temp drops and sub cooling have to be brought into play. Or some guys just go ahead and replace the TXV and filter drier and say bad TXV. When all the while it was a restiction.

@AIRMANHVAC

Жыл бұрын

Hey Robert, system operated fine when set to cool mode but not heat mode. After replacing the txv, it worked fine in heat and cool mode. Did you watch the video and see the sensing bulb was no longer attached to the txv? No question that the txv was the issue on this particular call.

I'm trying to follow along and I pretty much get it but what's confusing me is you're using the words condenser coil and evaporator coil when talking about a heat pump instead of saying indoor coil and outdoor coil. So I'm kind of guessing or assuming that you're talking about what I think you're talking about So it's starving the outdoor coil.

@AIRMANHVAC

2 жыл бұрын

You got it!

Hello , what if my pressures are equalized in heat mode and normal in cooling mode ?

@AIRMANHVAC

Жыл бұрын

You probably aren’t using the correct port for suction pressure. On heat pumps, you should have a true suction port. On most equipment it will be near the usual service ports….on Trane, American Standard, Rheem and a few others; you’ll have to remove a panel to access a true suction port.

@AIRMANHVAC

Жыл бұрын

This video may help as well kzread.info/dash/bejne/h41tqqmKaM_dnNY.html

@FernandoLopez-bq3zf

Жыл бұрын

Thanks for the info, appreciate it.

Why is Bible bloopers watching a Txv video😄

Weres the nitrogen purge

Pretty common on Lennox

Could a bad txv in the outdoor unit cause the high and low pressure to rise together to high levels and shut down on high pressure? Reversing valve is good

@AIRMANHVAC

Жыл бұрын

The outdoor txv should only affect pressures during heat mode. From what you’re describing, it sounds overcharged. I’d recover/weigh out all refrigerant. Then weigh it back in according to the manufacturer’s specs.

@ricardomeirelles4382

Жыл бұрын

@AIRMANHVAC we did that. It also works without issues in a/c mode. It's nuts, I've never seen a heatpump do this before.

Next time you should consider removing the filter drier from inside the heat pump and installing it close to the metering device inside the home. Also, a triple evacuation is best.