Heat Pump System Short Cycling
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- Опубликовано: 16 окт 2019
- This customer called with a complaint of the condenser unit occasionally going on and off rapidly (Short Cycling). Here is a short clip of what I found and the underlying issue with this heat pump system.
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Sometimes techs are in a hurry and only connect to the low side, easy to overcharge a system this way. Good video!
Love your videos. Wish you did more. Thanks for sharing
Agreed time and content is great. We need more
Close the liquid service valve and pump the system down. if the system does not hold a pump down and the liquid line service valve is properly closed. Replace the compressor. (Recip)
If the system holds a pump down cycle, inspect the metering device to determine if it is seated properly or too large.
If the system has a TXV, make sure the sensing bulb is properly insulated and in good contact with the suction line. If it is not, correct the problem. If it is, replace the TXV.
Great videos, definitely got a new subscriber.
Check the evaporator coil and remove the TXV's sensing bulb from the suction line. Check the subcooling, superheat and pressures again. ... Another test is to put the sensing bulb in ice water and checking the pressures superheat, and subcooling again. If they don't change, it's a bad TXV
Great video
2 years old... man that stinks. The underlying problem.... well said.
Good work
#Truth, great video! 👍
Ive been looking to get a pair of digital gauges how does the testo compare to the fieldpiece?
Some possible causes of low superheat are:
• Refrigerant Overcharge
• Metering Device Over-feeding
• Low Evaporator Air Flow*
• Oversized Equipment
• Low Condenser Air Flow
I explained what the issue was... and it has long since been fixed. 👍
Carrier has gone to junk. Great work!
Found a Carrier with the same problem today. Old 22 commercial system not really worth fixing. Hope all is well with You.
Multiple offender ❤️
I find this on carriers quite often and find the factory doesn’t clamp the bulb on real well. It might be as simple as that
Nope. Bulb was clamped tight with the factory locking metal band.
Yea joe I come across that on carriers too my brother.
Robert Cherry another thing is if they leave that grommet off the suction line and unit is pulling in hot air through that hole that is left
Any tip on what to check for. Ive found that its usually the txv gone bad.
What could be the problem if contactor at outside unit and relay in air handler keeps clicking when in a call for cooling? The unit is a Bryant and it's a heat pump
An evaporator coil that is receiving a higher than normal flow of refrigerant through the metering device will operate in a flooded condition. The system may experience high humidity complaints, compressor starting problems, or compressor failure.
Causes
Piston too large in fixed metering device
Dirty piston seat not allowing metering device to seat properly
TXV sensing bulb not insulated or in good contact with the suction line
Symptoms
The metering device isolates the high side from the low side pressure. When an overfeeding condition is present, the suction side of the system operates in a flooded state while the high side of the system operates in a starved state. The suction pressure will be high and the superheat low. The liquid pressure will be low and the subcooling will be low.
had a call like this at the same house 2 years in a row, the customer swears no one has touched the system, this last time, his next door neighbor pulls up and yells, "Hey Aaron!" to me, so I talk to him and he tells me that guy has had several people over to look at the unit, all the guy could do at that point was, drop his head and walk inside then pay the bill, the txv was working properly, the tenant just got a friend out that shouldnt be working on anything like this.
Does anyone know why is my heat pump freezes up when the temperature are below 34. It works find above otherwise. I call a tech and he added refrigerant assuming that was the problem. It still the same its cover in ice.
👍
Di minimus. 👍
You have to check your TXV Physically and your air flow by static pressure test and get your delta T - Do not jump right into conclusion that you have a bad TXV - First you though the issue was Overcharged system -that was not the issue - The issue was a TXV that went bad - You must check TXV before blaming others tech - Overcharged systems would affect compressor and cooling performance but would not damage TXV-
Dis you check the Air flow - Did you check if evaporator was clean -Static pressure - Did you get your delta T reading -
I explained what the issue was... and it has long since been fixed. 👍
Собираю себе самодельный тепловой насос на R22 фреоне. По принципу вода-вода
Your system was not overcharged - You just had a bad tXB - Check your TXV by the proper procedure
what if the reversing valve is leaking some past......
Then you would have different numbers.........
What is you liquid line temp?
I explained what the issue was... and it has long since been fixed. 👍
If you aren't getting superheat then you're TXV isn't doing what it's supposed to be doing it's probably bad.
Not exactly Dylan
Better just replace the whole system to be safe.
John I say replace it with a Goodman.
@Dylan Drymond That's not always the case.
the outdoor coil could just be dirty
Really? OK. Please explain how a dirty condenser coil would produce these refrigerant numbers.
@@HVACinSC clogged dirty coil could heat up and expand the pressure and look over charged, same way a dirty filter make a system to cold and makes the system look under charged another reason why a scale really helps and you know much you really take out
This is why you need to pay attention to temperatures of the refrigerant, Superheat and Subcooling instead of focusing on pressures alone. My green techs make that mistake all the time. If you pay attention to these important readings instead of just looking at pressures you will never get this issue confused with a dirty coil.
Not to mention that you should always verify the cleanliness of a system prior to diagnosing. Especially refrigerant related issues.
There is no way a dirty coil could give you the refrigerant numbers I showed in this video.