Heat Pump 12 Hight Pressure trips only in Heating
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- Опубликовано: 28 авг 2024
- Basic diagnostics scenario, High pressure trips only in heating mode but operates normally in AC mode.
This does not cover all the possibilities but a few to get you thinking about the heat pump cycle.
1st is the indoor and outdoor temperature low in the HP operating range. I have had techs call with this issue while the indoor or outdoor temperature was too high. generally the outdoors temperature should be below 70F and the indoor temperature below 80F. If the temperatures arehigh such as some days in the spring fall or in summer, this could cause the pressure to rise too high.
2nd, airflow! In cooling mode, low airflow will still be an issue but the customer may not notice but in heating mode the indoor (now condenser) coil is much smaller. With lack of airflow across the coil, the temp rises and the pressure follows. Airflow is usually more critical in Heat Pump mode than AC. This can be dirty blower wheel, blower speed, dirty coil, dirty or restrictive filter, blocked or undersized ductwork return or supply, too many registers closed and more.
3rd Indoor bypass check valve stuck closes or missing.
Even a fixed orifice can clog in one direction but not the other. Many residential TXV's have an internal bypass check valve inside. If this becomes clogged or restricted it will not allow the refrigerant to bypass causing a pressure drop and restriction. Some older TXV and all large commercial TXV use an external check valve that can cause the same problems'. If the TXV used does not have a bypass check valve at all then it will be an issue in heating mode.
4th a restriction in the liquid line such a a clogged filter drier or a kink in the liquid line.
5th The outdoor metering device is clogged up or malfunctioning
6th The outdoor coil has a restriction inside the tubing. This is more of an issue with micro channel
7th Overcharged. since more refrigerant is used in the cooling mode than heating mode, an over charge may show up in HP mode where the extra refrigerant as nowhere to go.
I have been a HVAC service tech for over 30 years, I worked on every thing from 500 ton chillers to 9,000 btu ptec units and this guy knows his stuff! A welcomed sight. Thank you sir! Merry Christmas Ty.
Thank you and Merry Christmas Robert!
It's not just that you are a great teacher. You have such great energy with a big smile that is enjoyable to see. Thank you.
I do love this stuff. So many things I had to learn the hard way over the years. Thanks for the compliment!
Nah this dude is so toxic is unbelievable. He literally spends his time on Facebook groups responding to every single post like the troll he is. We just kicked this twat from our group for attacking several business owners
Great lesson,Ty. Thank you for yet another year of fantastic and educational videos. You sir “moved the needle” in HVAC education.
Thanks Charlie!
Always enjoy your video’s. Always use to say when on doubt weigh it out!!
You are awesome! I wish I had someone like you to coach me when I was learning back in early 2000!
Wow, thanks!
Such a blessing
ACIQ inverter heat pump. says during heating mode, initial turn on ever. re-torque the flares while hot. Interesting for sure. Thanks for the tips over the year.
Thank you for the heads up! I looked through a few ACIQ instaltion PDF's and I cand find that. Which model is it that shows that?
@@love2hvacquick start guide 2023 V1.0 on hvac direct site. For aciq-24-hpb. "To ensure no leaks are present startup the unit in heating mode. While the unit is operating retorque the flare
adaptors (while unit is HOT). It is recommended to use a digital torque wrench."
Also note the dip switch settings in this quick start are not correct. Read what's on the unit itself. I confirmed this with hvac direct. Side not too, the indoor coil ACiQ-24-ACL vapor side is 3/4 like the HPB manual calls for. Very nice unit, super quiet.
Good video Ty. Thanks for sharing.
Great job Ty your a good teacher always like and learn from your videos have a merry Christmas and a blessed new year
Thanks Tim! You have a Merry Christmas and Happy new year as well!
Thank you for your time and tips. I was at this call just last month 38 years old GE heat pump, maintenance tech in summer from other companies overcharged the system which was not even necessary because it was basement his suction was low apparently added a charge, therefore in heat mode they started having issues, again 2 companies went out there couldn't figure it out guess too intimidating bunch of old Relays, wanted to sell new system, I went out there figured it out overcharged, pulled some out, no issues since then.
Integrity is gone
Thank you for doing right by the customer!
Unfortunately many of these companies want us to be salesmen instead of tradesmen.
They will hold weekly sales training up rarely technical training.
TY your one of the best technician and teacher I do like your videos nice videos
Unit was overcharged, thanks again!
Great informations. Learned many things from this channel. Thank you Ty.
Glad to hear it!
Great tips, Ty. Thank you.
Another great video. Thank you!!
Mr.Ty Branaman The Mr.Beast of Hvac .
Will you planing marking these great videos about walking cooler and walking freezer.
I have been learning from a lot and apply on job make money for my family.
I am gratefully appreciate your teaching!
Yes I will be doing some cooler videos. I'm trying to get some old panels and parts to make a demonstration
@@love2hvac Can’t wait.
And thank you so much again Mr.Beast of Hvac/R
Thanks and Merry Christmas
MERRY Christmas!
Great video Ty. Thanks for sharing with us
Thanks Jason! I have to get over there so we can hang out sometime.
@@love2hvac i would very much enjoy that
I have also seen that somebody uses a copper pipe that is too small for the liquid line and acts as a big restriction.
Other thing I have seen is that tam7 air handlers have something called enhanced mode which basically what it does is to run 50% airflow for the first minute or so to allow for the coil to warm up and it ends up going out on high limit for the first minutes until the blower is running at 100% airflow. What I do in those rare cases is to remove the blower delay.
Merry Christmas Ty.
This is true, there is a commercial building I consulted for that ran 3/8 to the wall then 1/4 most of them way and again 3/8 before the air handler. some over 100. It was a mess they hose to reduce the charge and deal with performance loss rather than change all the liquidines.
I did not know you could turn the delay off on the Tam7. Thanks, will check it out.
You have a Merry Christmas
He's looking at the wrong meter device!!! Ty should be looking at the meter device at the outdoor condenser. Remember Ty said everything works "great in cool mode" but in heat mode the system turns off due to high pressure. That would be the metering devise at the outdoor condenser. Merry Christmas all.
You might want to rewatch the video and take some notes.
Merry Christmas
Great video
Airflow cfm might be ok but if it can't get the room air and it's leaky before and after the unit, pressure can stay high.
Hi Ty!
In walk in cooler or freezer in wintertime should use weight method in charge or checking refrigerant?
Thank you and have a bright future.🌹
If it has a head master it will affect how it's charged in low ambient.
With the variety of condensor evaporator matchups and accessories, it's difficult to get manufacture numbers on weighing in.
In any case when it's pumped down, the receiver should never be more than 80% full.
Ty, what’s your feeling about looking for a restriction using temperature probes before and after any suspected part? ( drier, txv in bypass, etc)
Temperature is a great way to find a restriction. Pressure is the best way but we don't usually have the luxury of a pressure port before and after. It is possible to have a restriction without a temperature drop as Bryan Orr found out in a lab test.
Hi Mr ty
Is it possible to explain about the heat pump system with good pressure and the suction line is hot above 150 degrees but supply air temperature is not going to be above 80 degree
👍👍
Can you please do a video on heat pump going out on high pressure in cooling but work in heating
So what if liquid line pressure is slightly high in cooling but still cools and in heat runs for 5 min if that and trips and resets itself
So if we have a pressure drop across the TXV we have a restriction. And since the relationship between pressure and temperature is there, we'll also have a temperature drop. Can we use clamp probes across our TXV to see restrictions like a liquid line filter drier? I just encountered this issue on a new install (I'm a warranty tech) and I opened up the TXV to get flow and it worked. But what's going to happen when we go back into cooling season, I'm sure I'll have low superheat and have to adjust it again. It seems like most of our problems are installation induced.
A TXV is suppose to have a pressure drop across it when it's metering.
When it's in bypass either an internal or external check valve should open bypassing the TXV so there is no pressure or temperature difference in that mode.
In cooling mode the outdoor metering device is bypassed and the indoor will have a pressure and temperature drop.
In heating mode the inside metering device should be bypassed and the outdoor metering device used.
If you are saying you have a TXV indoor, and you had to open it all the way up to work in heating mode, then there is a problem. Either the check valve inside is stuck closed, an external check valve is stuck closed, or it is the wrong TXV for the application that does not have an internal check valve.
#1 look to see. If it has an external check valve inside. If it does it may be stuck closed. If the external is stuck closed replace it and go to #4 If it does not have an external check valve...
#2 check the TXV model number with the manufacturer. If it does not have an external or internal check valve for bypass, replace it with one that does.
#3 if it does have an internal check valve and it's causing a restriction in heating mode, replace it as the internal check valve is likely stuck.
#4 there is a reason it stuck so a system clean will need to be performed. Flush with nitrogen, check and clean the strainers of the indoor and outdoor metering devices, flow nitrogen while brazing, replace the biflow liquid line filter drier, pull a very deep vacuum and recharge.
Wow! Thank you for such a detailed response. You're one of the few that actually responds and I learn so much when you do. HVAC is truly one of the most difficult trades out there. It's non stop.@@love2hvac
can reversing get stuck and send high pressure on both lines(high and low ) on heating mode? both pressures rise equally on my gauge on heating mode, but on cooling mode works just fine
Both lines will be high pressure in heating mode. You will have to use the true suction port for your suction pressure. I have a video on that in this same playlist.
@@love2hvac yes, but pressures should be equal and rise the same, to the point to stop the compressor?
@@eretza666 not all units have a high pressure switch.
Reversing valves rarely fail but are often blamed. They are misdiagnosed way to much. I have been to 100's of calls where company A said it was a bad reversing valve and I find something completely different. In all the years I have had to change 6 3 of those where overheated when someone tried to change them, 2 from debrise and 1 that was leaking refrigerant to the atmosphere.
A failed reversing valve cannot send high pressure to the suction and discharge at the same time.
@love2hvac thanks , that's what I needed to know .Rules out reversing valve, now if the txv is not by passing, that should be the cause for pressure to rise if air flow is fine and everything else is clean (coil.filter)
Done you think? Thank you for replying
All information presented good BUT BUT speak slowly PLEASE ! I had to pause the video all the times ! You're explaining complex technical issues so please give time for people green techs one as well as seasoned techs time to digest the info you're trying to convey Many many thanks.
Maybe the person needs a new home
what genius created micro channels save a buck or 2 on power bill ? less Refer needed to transfer heat ....I don't know & yes Carrier cheaped out putting piston In LL service Port directly connected & not @ distributor another Genus move -Harpy HVAC_KIng