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The thread is 11 years old.
Please don't awaken the dead.
Could be literally.

Goodman Factory TXV Kits Definitely have a depressor on the flare, but I still have a habit of removing the valve core just to be safe.

No - still about schrader core left in and no depressor.

are you talking about if the stem were leaking?

What I believe happens is very small amount of pressure from the high side enters into chamber where it never enters the low side. Hence keeping higher than normal closing force.

Now if the equalizer were never connected would be the only way to have wide open valve.

ive never witnessed a clogged or capped off tube. but going by the troubleshooting guide i linked it saids a plugged tube would have low suction and high superheat

if its plugged it would be the same as not connected

Originally Posted by SBKold

I understand what you are saying but how does a non bleed valve work? I though with the rising suction pressure forces valve closed. With lower suction pressure ie 0 and warm bulb shouldn't valve tend to open.

When the compressor shuts down the low side pressure will begin to rise, increasing the closing force. The valve closes.

Originally Posted by gravity

i found another pdf.

it also shows high superheat/ low suction is a cause of a plugged external equalizer tube

http://www.hintech-electric.com/cata...lp%20guide.pdf

scroll to bottom for troubleshooting

Plugged to me is different than not connected. If plugged it would read higher than normal evap press.

If the evap pressure force acts in the closing direction and it is non existing due to no schrader depress wouldn't you assume valve would stay wide open.

That is a neat pdf and it will be kept. I appreciate it.

i found another pdf.

it also shows high superheat/ low suction is a cause of a plugged external equalizer tube

http://www.hintech-electric.com/cata...lp%20guide.pdf

scroll to bottom for troubleshooting

Also non bleed valves are a good thing as long as recip compressor has start component.

Huge efficiency gains as well as increased dehum due to warm refrigerant not being able to warm up evap. Cycling losses

Originally Posted by gravity

im pretty sure by looking at the design of the valve. the equalizer tube(suction pressure) puts pressure on spring which is driven by the bulb pressure. if the equalizer was blocked the valve would shut down.

maybe someone else can chime in. im not at my computer.

I understand what you are saying but how does a non bleed valve work? I though with the rising suction pressure forces valve closed. With lower suction pressure ie 0 and warm bulb shouldn't valve tend to open.

Should be fine. I've installed a few and the equalizer line had a schrader depressor. Zero issues with many a mile on them.

Originally Posted by millertime77

Read most of the PDF, a good one indeed, and figured out that it is 2 oppossing forces that control the flow of refrigerant, the charge in the bulb against the back pressure leaving the evaporator. So I guess I was wrong in my thinking that pressures equalize in a txv system, they don't? They do though equalize in a system using a piston as a metering device?

Yes many TEV's do equalize. However they do it in a manner differently then you first thought. Basically there is hole drilled in the valve body. They are different sizes and Sporlan stamps the size of the port next to "BP" on the side of the valve.
York for example on residential systems do not have this so the pressures dont equalize.

OF course on captubes or orifices the pressure does equalize.

THere is only one opening force on a TEV. That is the bulb which is pushing down on the needle. Warmer bulb, Valve throttles open.
THe Closing force is evaporator pressure and spring pressure.

In regards to the PDF Gravity posted I am pretty sure when they are talking about high superheat/ low suction being a blocked equalizer they are referring to the seal around the pushrods leaking. This gas cannot escape because of the blockage and pushes up on the diaphragm. This counteracts the opening force of the valve..

ok found it.....this should clear it all up

http://www.sporlanonline.com/10-37.pdf

im pretty sure by looking at the design of the valve. the equalizer tube(suction pressure) puts pressure on spring which is driven by the bulb pressure. if the equalizer was blocked the valve would shut down.

maybe someone else can chime in. im not at my computer.

Read most of the PDF, a good one indeed, and figured out that it is 2 oppossing forces that control the flow of refrigerant, the charge in the bulb against the back pressure leaving the evaporator. So I guess I was wrong in my thinking that pressures equalize in a txv system, they don't? They do though equalize in a system using a piston as a metering device?

Originally Posted by dachipsta

I wouldnt leave a valve core in for something like that because anytime it would need to be taken off the system will be empty of gas anyways. If not and for some reason the system is slow to equalize, you will wind up with compressor starting issues if the cycles are close together, sometimes even when they arent. Not as much if you have start componants but why go thru the hassle. Take out the core.

understand that its all based on what the equipment manufacture designed it for. Trane heatpump air handler coils come with the core in but you must remove it before you install the TXV. the equalizer cap tube with the flare end, is not equipped with a depressor. if you leave the core in and install the TXV and start the unit it will not equalize the TXV in respect to the evap coil causing problems with the performance of the TXV and overall system. I would follow the manufactures instructions. every one is different.

Think that's backwards