Heat pump 13 stuck check valve

Heat pump with a stuck check valve.
Indoor vs outdoor, stuck open vs stuck closed.
From taking a test to diagnosing a live systems lets explore a variety of stuck bypass check valves in a heat pump application.
Some of these will be be more applicable than others but the idea is to get you thinking about the heat pump cycle.
Outdoor check valve stuck open in AC mode
Outdoor check valve stuck open in Heat Pump mode
Outdoor check valve stuck closed in Heat Pump mode
Outdoor check valve stuck closed in AC mode.
Indoor check valve stuck closed in AC mode
Indoor check valve stuck closed in Heat Pump mode
Indoor check valve stuck open in Heat pump mode
Indoor check valve stuck open in AC mode
Special thanks to JD Kelly student of HVAC for the awesome graphics!

[@JasonKurtz-uc2xy]

Hello Ty. I always dreamed of being a student of yours. You have a wonderful personality and I love the way you break things down. We’re probably around the same age, but I’m just starting out in the field. It’s been overwhelming and daunting at times, but I presume it’s going to be like this for awhile. You are a great teacher and a great man. I love the inner joy that you bring when you surround people. You are like a beacon of light. Even though we don’t know each other personally, it an honor and a pleasure knowing you from the social media platform. Take care.

[@kentuckyhillbilly455]

Thanks for still being around. You are a valued member of the HVAC community. I have definitely learned a lot from your videos. This isn’t my line of work but a lot of it applies

[@benefits941]

currently in school for hvac you are great help

[@RATCHETMAN1001]

tom lech sent me to watch you, i do automotive ac i thought because the way we are taught we were doing ac correct( boy was i wrong) in my industry is so far behind. i love what you are teaching. not every thing applies to us but most of it does. i thank you and tom so much. wow wow wow

[@love2hvac]

Awesome!! Tom is great. We have lots of people on the HVAC side that don't know either. It's about learning and sharpening our skills. I love it when people want to learn!

[@RATCHETMAN1001]

@@love2hvac im 67 and most of my life i love to learn new things.i dont no if i would want to be a teacher cause so many dont want to learn and that would disappoint me i think.but watching and learning from u guys gets me excited like a kid with a new toy. i ll keep watching till i get the info i need ,many thanks

[@chesstime356]

Another good video as always I like your videos. I think I will be watching this video few times again to get more out of it. I do most of the time residential maintenance work… heading towards fully service technician…

[@love2hvac]

Thank you! I am so glad they are helping!!!

[@JanosHoyos]

Hi Ty 2 months ago i asked you about doing combustion analysis and you responded remind me closer to heating season which is now. If you do decide to do a session on combustion could you please address troubleshooting, diagnosis and adjustments. Thanks and have a great day. Best regards Victor

[@nakiapringley5391]

Great video.

[@jimmylanders2175]

Happy New Year Ty! Love your teaching and videos. Other than gauge pressure and temps and SH and SC, can you also do a temp across the metering device to prove prior to change out?

[@love2hvac]

A temperature reading across an open check valve is a great way to check. It should be the same temperature, if not it's likely restricted If the metering device is engaged there will be a temperature drop but there is in value in what it should be

[@mtbbiker6401]

Hi Ty. I have a Trane Heat Pump. There is a bypass check valve at the outdoor unit which I believe is a ball type check valve that allows refrigerant to bypass the outdoor TXV. There is no such bypass valve in the indoor unit. This means the indoor TXV must have a built in bypass when operating in heat mode. Is this the case? My mom also has two similar Trane Heat Pumps. One has a similar bypass on the outdoor TXV but the other unit does not have this extra bypass routing, only the outdoor TXV. I guess there are TXVs designed to allow flow of refrigerant in both directions. My outdoor unit was making a chattering noise while running and pretty loud after the compressor shut down for a few minutes (in cooling mode). I diagnosed the noise coming from the outdoor check valve. Apparently this is a known issue with older Tranes (2010). Trane released a clip on magnet part to help eliminate the noise. I suspect that after the compressor shuts down, refrigerant is flowing back through the valve which causes the noise after shutdown. Hopefully it won't harm any other components. I have posted a video of the noise on my channel.

[@love2hvac]

The Trane check valve rattle is a known issue for sure. I likely to damage anything and the magnet kit helps with the noise. The indoor TXV is usually built with an internal bypass check valve. Some Trane TAM models use an electronic expansion valve inside. They are programmed so the stepper motor of the EXV opens all the way for bypass. Excellent question!

[@mtbbiker6401]

@@love2hvac Thanks for the reply. I was a little perplexed when I didn't see external bypass piping on the indoor TXV like it has on the outdoor unit.

[@oscarguillen1729]

Are there any cases where the reversing valve or compressor will be the issue in a high suction pressure scenario? If so, would it be possible to make a video on how to troubleshoot such issue? Thank you for the videos you make and all you do for HVAC community!

[@jpechacek80]

3 ton residential package unit 410A . Compressor trips on over pressure in Heat Mode (>500psi). I blocked the outdoor fan with a cardboard so it wouldn't trip. (temporarily to measure) LO side P=110, T=38.6 (suction) Tsat=35.5 => 3.1deg superheat. HI side P=350, T=80 Tsat=105 (25deg subcool!) (Downstream from the TXV bypass ) After watching this video, I need to recheck upstream from the TXV bypass And look for a temperature difference across the TXV that is supposed to be bypassed in Heat Mode. If stuck, is there a way to get it unstuck without opening up the system?

[@love2hvac]

Sometimes a magnet works, some times tapping it but those are often temporary.

[@bernardocisneros4402]

Thanks for the video. Do you prefer using a manual (analog) or digital manometer?

[@VERYEASYTOLEARNHVAC]

thanks ty,,,, when you make electrical & control wiring related videos??

[@love2hvac]

It's coming! Work and bills keep getting in the way

[@mikev.1034]

👍👍

[@AngelRodriguez-qg5zq]

Thanks Ty and happy new year!

[@love2hvac]

HAPPY New Year!

[@NizarOkab]

On a previous 410a charging video, you charged the unit through the low side. Is it safe to add liquid knowing that’s it going to the compressor?

[@love2hvac]

Throttling it in, very short burts allowing to to expand to a vapor before reaching the compressor.

[@ddcws1]

I'm following you so can an internal txv check valve fail?

[@love2hvac]

Yes

[@ddcws1]

Reason I am asking is because we have had an issue with a trane package heat pump. Last March It was locking out on a in-timed defrost 8 and 9 fault. When testing we found the tech determined it to be on the cooling side. The indoor txv was restricting when going into defrost he replaced it. It happened again. I go out there and looks to be that there is a restriction on the cooling side. We just replaced a txv so I called Trane and they said indoor coil was plugged with the readings I gave them. Replaced coil w/new txv and tested and everything looked okay. Tested defrost numerous times and no issues. 9 months later (Dec) issue is happening again. Same thing in timed defrost. I tested it and no issues. Forced defrost things looked okay. Forced again and when it came out suction pressure fell below the low pressure switch cut out. Switch opens up at 35psi and I was near 30psi. Granted I had bypassed low pressure switch while currently testing thinking maybe it was the issue but it was good. Had no significant temperature drop across filter drier so Determined outdoor txv was issue. Replaced and no issues. I have a picture of the filter screen at old txv and you can see its plugged. Wondering if that was the actual issue the whole time. If the screen is restricted wouldn't that also affect it bypassing correctly?

[@ddcws1]

@@love2hvac When I did the indoor coil repair I flowed nitrogen. I always flow it anytime I do a repair. Just wanted to let you know.

[@love2hvac]

@@ddcws1 yes if the screen is clicked it would affect bypassing. Most of the Trane units have an external check valve outside

[@ddcws1]

@ it's a residential package unit. I don't believe there is an external check valve.

[@salvatoregiovanni8967]

Great content and scenarios, but for this content to be geared toward students, your presentation speed is waaay too fast. Slow down!

[@JanosHoyos]

Please