CapillaryTube, what exactly is it ?

I have often wondered, just exactly what is a capillary tube? is it a modulating refrifegerant control or a fixed oriface metering device ?

It responds to the load as the TXV does, but also looks and feels like a fixed oriface.. so just what the heck is it ?

Fat Eddy

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Reply to
Fat Eddy
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Ive often wondered what a spammer getting nailed is. is it like a bitch getting slammed to the ground and getting rolled, or it it like a newborn puppy whinin for momma?

Reply to
aka-SBM

Yea, I'm getting tired of his spam too. He posts under another name as well and responds to his own posts Rich

Reply to
geoman

and when you get REALLY tired of it, you'll quit yer bitchin and stop reading his posts. maybe.

Reply to
gofish

So you really don't know ? you have no clue what it is do you .

Reply to
Fat Eddy

Wait, you forgot something:

[ Fat Eddy [
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So what kind of money-per-click are we talking about here?$?

-zero

Reply to
zero

I know....but I ain't telling

LALALALALA

Reply to
daytona

It's a wire with a small hole going right through middle. Some people use them to meter refrigerant, others use them to pick their teeth with. :-)

...Ron

--

68'RS Camaro 88'Formula 00'GT Mustang
Reply to
RSCamaro

Some clamp em down to see if they can get by without a piston....

Reply to
aka-SBM

The cap tube is a fixed metering device that is the correct diameter and length for the load it is designed to handle. The outdoor temperature affecting the head pressure, to a small extent, affects the rate of flow. There needs to be a strainer or filter dryer just ahead of the cap tube as it is easily plugged.

A TXV is far superior for regulating superheat and subcooling of a variable load.

- udarrell

Reply to
udarrell

he knows this without going to hvactalk.com ! Amazing

Reply to
geoman

Nah, ya' don't need one. Just put a pinch-off tool om the liquiid line, and squeeze it down until the superheat is satisfactory. But it only works after installing a used run capacitor, about 50% over sized.

Reply to
~^Johnny^~

But there is a strong argument out there that says they are a modulating metering device, theoretically I suppose they are, they do modulate flow to the evaporator in response to how much subcooling they have in the capillary tube itself, the more subcooling they have the more refrigerant they will meter through the tube, the lower the subcooling and the less refrigerant passes, it tends to modulate , where as a fixed oriface has no ability to respond to the load.

Fat Eddy

Reply to
Fat Eddy

The capillary tube does not have the ability to directly adjust to the heatload on the evaporator coil as the TXV does. Therefore, if "for any reason" the heatload drops way off which also lowers the coil's pressure compared to the highside resulting in increased flow into the evaporator coil. Therefore, if the outdoor ambient is very hot it will flood the evaporator with liquid and slug the compressor. Alternatively, the TXV will throttle the refrigerant flow down in a direct attempt to maintain enough superheat to help protect the compressor.

The cap tube does not stop the flow of refrigerant when the unit cycles off, which reduces pressure differentials and starting torque but also can reduce the life of the compressor due to some possible compressor slugging on startup.

Both the cap tube and the Fixed Orifice will respond to an increase in the evaporator load in respect to how much that increases the highside pressure and thus the flow through the restriction. However, I see very little difference between those two devices; the TXV is far superior to either of them. Eddy, I would like to see that strong argument that a cap tube can modulate subcooling or superheat in a proper way. - udarrell - Darrell

Reply to
udarrell

Not looking to argue it, its just that it is classified as modulating metering device due to the action and reaction that happens within the bubblee length of th etube,,, it makes it a modulating refrigerant device the same class as the TXV, however is no where near as efficceint as the TXV.

Fat Eddy

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Reply to
Fat Eddy

Naw thats too easy.

Reply to
ftwhd

Its a fixed metering device.

Reply to
ftwhd

Is not

Fat Eddy

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Reply to
Fat Eddy

Its classified as a fixed meter device and a TXV is classified as modulating. I suppose you could say a cap tube is more of a pressure reducing device but I wouldnt try to stretch that to mean modulating.

I know where you are trying to go with this modulating bit but it doesnt really modulate open to closed or vise versa the way a TXV does.

The inlet pressure determines the flow rate and the modulation of the flow rate is dependant on the bubble length of the cap tube.

Reply to
ftwhd

Thats not true, the flow rate is determined by the quantity of the bubbles in the bubble length. and thats what modulates, the amount of gas in the tube, because vapor travels at a different speed than liquid does.

Reply to
Fat Eddy

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