Heat pump 13 stuck check valve
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- Опубликовано: 29 дек 2023
- 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!
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.
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…
Thank you! I am so glad they are helping!!!
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!
Great video.
thanks ty,,,, when you make electrical & control wiring related videos??
It's coming!
Work and bills keep getting in the way
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?
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
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?
Sometimes a magnet works, some times tapping it but those are often temporary.
👍👍
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.
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!
@@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.
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?
Throttling it in, very short burts allowing to to expand to a vapor before reaching the compressor.
Thanks Ty and happy new year!
HAPPY New Year!