HVAC 089 fixed orifice piston closer look inside 

After readimg that paper I like the cap tube over a piston. However I still prefer a TXV or EXV

@@love2hvac I posted reply to that with another paper I found by the same author, more elaborate. I tried to put the website name but youtube made a link so it might have gotten dumped for that. THEORY AND FIELD PROBLEMS OF THE CAPILLARY TUBE By HENRY EHRENS is the name of the paper.

I dint see the link you posted but I found it and I posted it to your reply and to the description on the capillary video. Thank you for that. I love this kind of information and discussions!

@@love2hvac The paper cited in my comment above is different than the paper I posted about originally. Apparently a fuller version. Very interesting as it has quite a few troubleshooting scenarios. Even a description of an invention that used to be available for testing cap tube and compressor efficiency before adding refrigerant when changing a strainer.

Thank you

Exactly! I will be getting to it soon. I am building the ground work first.

@@love2hvac I see 😊 and I'm following along. Hope you don't mind me using your techniques to teach others 😉.

Some can come out others are permanently, you can replace the fitting or unsewat it and clean it then rebraze it

First I would check airflow. It's the most overlooked part of Air conditioning. Next I would look at refregerant restriction such as filter drier, kink in line, screen, or piston is too small.

I dont understand how those bad installers keep getting away with it.

@@love2hvac money talks (but the other way around 😂)

If the AC was exposed like furniture, cabinets, doors, and landscaping people would spend much more money on it.

@@love2hvac now I understand why they started with wall mount minis 😂

There are a lot of Hacks out here that don't have a clue about what they're doing and earning a good living.

The compressor is moving volume of refrigerant and changing the pressure from a low pressure to a high pressure. It cannot do that alone, it works with its teammate the metering device. The metering device restricts/meters a volume of refregerant and causes a restiction of hi pressure and low pressure. The compressor needs the metering device to be able to build the high pressure and to create the low pressure differential. The low pressure is causing thebrefregersnt expansion to allow the refrigerant to boil. The evaporators job is to make sure to boil all the refregerant to a superheated vapor to protect the compressor and the condening coil is designed to reject the heat the evaporator collected and the heat from the compressor. Evaporator coils are some times much larger and sometimes smaller depending on how much dehumidification is needed. Some equient matches a 3 ton compressor to a "4" ton evaporator. The evaporator is nothing more than a heat exchanger. Using a larger evaporator allows for more superheated vapor and can boost the effecency. But the metering device would still need to be the 3 ton matching the refregerant volume of the compressor. Let's say you have a 4 ton evaporator coil and left the 4 ton metering device in on a 3 ton compressor. The larger opening would allow more refregerant threw and less pressure on the high side. It may not be able to build enough pressure on the high side to raise the saturation temperature high enough to reject the heat needed. Then it allows too much flow in on the evaporator causing the suction pressure to be to high meaning the suction saturated temp is too high and it wont be a low enough temperature to dehumidify a tech would add refregersnt to raise the head pressure but that ends up flooding the evaporator coil with refergerant that gets back to the compressor.

@@love2hvac Good deal follow up question. Ive worked on a trane unit with a 7.5 ton compressor and a 5 ton metering device oem txv Can you explain the benefits of this?

Do you have some model numbers?

On an AC, or HP in AC mode no. On a heat pump in heat mode possibly.

Not necessarily

I am so sorry to hear that. Yes that will damage the system but it's difficult to prove and fight. I really hate that people are out there doing that.

Can you explain exactly what gets damaged and why? The compressor now is making a buzzing sound and the evap coil sounds like rushing water.

Without a metering device the compressor will experience liquid floodback that washes oil away from the top bearings. Without lubrication on the top bearing and orbital scroll metal to metal wear occurs greatly reducing the life of the system. Second, not pulling a good vacuum leaves moisture in the system. The moisture reacts with POE oil that turns into an acid that eats away at the evaporator coil, condensing coil, Cooper lines and compressor windings. When copper is eaten away from the system, it floats through the system until it plates on the hottest part of the compressor causing copper plating on the bearings until it's so thick the compressor can't start anymore.

Thank you for the great feed back.

Chatleff is a piston style metering device. Aeroquip are stainless steel hydraulic hoses and valves made by Eaton from what I can tell. Maybe a name not used in Australia for a refrigeration fitting.

Chatleff uses the teflon seal. It's been a while since I've worked with the Aeroquip but I believe they use an o-ring inside similar to the preset line connections. I will have to look it up.

Thank you!

Some do some do not

some you can, some you cannot very easily

@@love2hvac Sorry my english is not very good

@@love2hvac me refierro si se puede cambiar la red interna.

@@love2hvac If not easily, how would you go about?

Wait for my video on it.

If you take it out you will have low subcooling and low superheated with poor cooling and sooner or later a dead compressor

@@love2hvac how would you know? Have you ever tried it?

@@CubanMofo I have seen systems where someone did the exact thing. One was a new install and 4 where to replace dead compressors only to find someone at some time took the metering device out.

@@love2hvac weird they would get rid of it in a new install.

rx11 or soaking it in 91% alcohol