TXV equalizer tube: does it feed liquid refrigerant

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TXV equalizer tube: does it feed liquid refrigerant

Рет қаралды 42,545

Күн бұрын

This one discusses the equalizer tube. Does it feed liquid refrigerant into the suction line. This video is part of the heating and cooling series of training videos made to accompany my websites: www.graycoolingman.com and www.grayfurnaceman.com to pass on what I have learned in many years of service and repair. If you have suggestions or comments they are welcome.
If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.

Пікірлер: 73

@BLAZENYCBLACKOPS 8 жыл бұрын

I really wish that these components that you open up to show what's going on inside were shown to me when I went to union school years ago, I'm a very visual person, when I can actually see what's happening it really sticks in my mind, thanks for doing what you do it's very helpful.

@grayfurnaceman 8 жыл бұрын

Welcome GFM

@tj8210 9 ай бұрын

Interesting.... great work. I agree. If any liquid woukd get by that need would evaporate immediately due to oressure drop

@rodgraff1782 Жыл бұрын

Equalization,weather internal or external, bulb goes upstream on factory systems. On built up systems, close to equalizer as possible. Equalizer is a closing force. Superheat spring is closing force. Powerhead is an opening force

@xrayexplorer 7 жыл бұрын

Great video series. I recommend placing the bulb upstream of the ext. equalizer line in any classes I do on TXV's and usually get a few looks of disbelief and or eye rolls. I was taught this probably 25 years ago by a senior journey man and it stuck with me. Once I observed where the liquid was leaking past the push pins (I assume anyways) resulting in ~ 4 degrees of depression just down stream of the external equalizer line. I noticed sweat on the ext. line and put a thermistor about 2 inches down stream. Sure enough the temperature was lower there. TXV was not underfeeding, however the superheat was set a few degrees below factory setting so I suspect somebody must have adjusted it to make up for the temperature drop.You are correct that manufacturer's are placing the bulb down stream of the line. Can't really blame them as picking a spot for the bulb is getting harder it seems these days.Keep up the great work!!!Jamie

@grayfurnaceman 7 жыл бұрын

Thanks for the thoughts. GFM

@michaellicitra7632 7 жыл бұрын

Jamie K has it right. Great videos!

@hg2. 5 жыл бұрын

@@michaellicitra7632 Best HVAC videos on KZfaq.

@ryanmalin 6 жыл бұрын

If anyone knows more please share. I think the Danfoss txv uses the equalization tube to divert excess refrigerant under low load. I have stores with all Danfoss valves that we've change to all sporlan and the floodback stopped, seemed to gain capacity due to less floodback. I might be wrong but when I see a sporlan txv with frost on eq tube, I fix it, Danfoss Valves typically frost the eq tube. Only observed from working on the crap

@Rueuhy 7 жыл бұрын

This reminds me of a class I sat through for gas valves. The equalizer tube is much like the small channel feeding into the bottom of the diaphragm of the gas valve controlling manifold pressure. The spring tension on the manifold actually fights against the inlet pressure to control the manifold pressure. The instructor called it a controlled leak going on inside the gas valve which is kind of a good way to think of it. And, if any crud plugs up the inlet channel feeding into the bottom of the diaphragm chamber this stops the gas valve producing the correct manifold pressure. It's interesting how similar the principle is between a refrigerant txv and a combination gas valve is for a gas furnace.

@grayfurnaceman 7 жыл бұрын

They are quite similar. GFM

@dennisnoone7427 8 жыл бұрын

thanks for cutting one a part, never knew how equalizing tube was hooked up inside the txv.

@grayfurnaceman 8 жыл бұрын

+Dennis No-one Welcome GFM

@derrickowens3072 8 жыл бұрын

all Rheem ruud air handlers and furnace coils show in the installation manual to mount the bulb downstream from the equalization tube I never even thought about it hurting anything good video!!!!

@marinobravo1 8 жыл бұрын

A really good video. Better than in class teaching lol Thanks and keep it up!

@OcRefrig 7 жыл бұрын

Good video. Never seen a Txv cut away like that. Very cool.

@teravolt6113 5 жыл бұрын

You can also get an automotive block-type TXV and easily disassemble and reassemble it, done it once to check if the valve seat was nicked or it was cross-charged (it was taken from a car with a variable compressor, and the valve isn't supposed to completely close with these compressors, just like it didn't when i tried to blow air through it right after freezing its power head).

@et5712 8 жыл бұрын

perfect video, great cross-sectional view making understanding simple. Thank you GFM

@haunguyen-tr2zm 4 жыл бұрын

thank you for sharing. It is a very useful knowledge.

@grayfurnaceman 4 жыл бұрын

Welcome GFM

@stefanhasenbroek9752 8 жыл бұрын

The equilasation line cant put liquid there because it is on the suction line going to the compressor, and it is not a flowing line. And the sensing bulb always needs to be behind the evaporator coil that you want to have metered for superheat. Sometimes you put the equalasation line right behind the evap coil if you need a perfect superheat management on the coil, some systems require this. ( sorry for me bad english im dutch ) like your video's a lot !!

@grayfurnaceman 8 жыл бұрын

+stefan hasenbroekv Thanks for the thoughts. GFM

@stefanhasenbroek9752 8 жыл бұрын

+grayfurnaceman no problem, do you do Large chillers as Well? Would like to see video's of that as well. Ill keep looking! Gj on the vids

@mbburry4759 5 жыл бұрын

Behind the evaporator? When it's still liquid???

@teravolt6113 5 жыл бұрын

Block type automotive TXVs are all externally equalized even though the evaporators are usually very small (supposedly to minimize hunting, since some compressors require a dampened TXV response to function properly). The refrigerant that flows out of the evaporator directly exerts a force on the diaphragm.

@teravolt6113 5 жыл бұрын

@@mbburry4759 Perhaps he just means "right after the evaporator's outlet".

@hg2. 5 жыл бұрын

Min 3:40 -- FINALLY figured out what that "equalizer tube" is for: high-pressure liquid-or-gas is going to sneak up the gap in those push rods into the valve area under the diaphragm and distort the valve action, so an "escape" has to be arranged for that pressure (hence the equalizer tube). Phew. (correct?)

@grayfurnaceman 5 жыл бұрын

Actually, no. The The equalizer places the evaporator in the same pressure area as the valve. This eliminates the pressure drop of the evaporator tubing. GFM

@hg2. 5 жыл бұрын

@@grayfurnaceman I'm referring myself to another GFM video, kzfaq.info/get/bejne/n7GUiKZ6l9umhJs.html : at Min 3:40 "... it's spring pressure + low-end evaporator (equalizer) pressure vs. bulb pressure.

@nicholasceea4109 8 жыл бұрын

Nice video and great job on the cutaway.

@grayfurnaceman 8 жыл бұрын

+Nicholas CeeA Thanks for the support. GFM

@geojor 8 жыл бұрын

thanks for sharing your expertise ...

@heavydiesel 8 жыл бұрын

I think its a hang up from when txv's/tev's were made with poorer manufacturing tolerances, I've seen them installed both ways and not noticed any difference in operation. Having said that, I have also seen valves fail and dump enough liquid down the equalizing line to cause the valve to close in refrigeration applications due to old age etc.

@grayfurnaceman 8 жыл бұрын

+heavydiesel I have to agree on that. I have also seen them done both ways. GFM

@hvacrjunky6119 8 жыл бұрын

+grayfurnaceman I believe that when this happens then the equalizer line is frosted over, but maybe this only happens in lower temps such as refrigeration??😎

@hvacrjunky6119 8 жыл бұрын

+HVAC/R Junky Nice cutaway on the valve!😎

@jimbola77 8 жыл бұрын

thank's gray excellent video thank' s for sharing!!!

@grayfurnaceman 8 жыл бұрын

+jimbola77 Welcome GFM

@Guyhakverdi 8 жыл бұрын

Your cutaways are amazing :) Do you also have adjustable TXV cutaway?

@grayfurnaceman 8 жыл бұрын

+Guy Hakverdi You know I haven't done that. Good idea. GFM

@onlyulee866 4 жыл бұрын

How do you determine TXV Spring psi?

@vernroach3413 5 жыл бұрын

If a guy or a girl, can't learn from this man, they just can't learn.

@jamesfields4149 8 жыл бұрын

Good video and explanation GFM

@AutoDudes 8 жыл бұрын

Awesome video! I love the cut away! Quick question. I've been told that the sensing bulb has a "different kind of refrigerant" in the bulb and the tube, is that true?

@grayfurnaceman 8 жыл бұрын

+Kevin R It depends on the valve. Most A/C valves have the same refrigerant as the system. GFM

@AutoDudes 8 жыл бұрын

+grayfurnaceman excellent, thank you!

@grayfurnaceman 8 жыл бұрын

+Kevin R Welcome GFM

@teravolt6113 5 жыл бұрын

Most automotive TXVs have a mix of refrigerants and an absorbent charge inside the power head (no "bulb" on these). This is called "cross charged" and allows one to set the superheat vs suction pressure curve as needed by the application. Such a charge allows steady operation of the TXV and prevents it from closing completely so that variable displacement compressors can both adjust the displacement steadily (some of them rely on the suction pressure to adjust the displacement and the suction pressure, to keep the evaporator from freezing, and go haywire when the TXV hunts superheat) and so that the compressor can always be supplied with oil even when the evaporator is very cold. On my channel i test such a cross-charged TXV myself and show how the metering pin slowly returns open after partly closing due to a cold power head. On the other hand a valve that contains the same refrigerant found inside the system is called "parallel charged" and may "hunt" superheat more than the first.

@engr-mq1dv 5 жыл бұрын

Sir if sensing bulb below is broken, does Equalizer work same like Sensing bulb? Or both have different fuction. Can u pls explaing both function clearly. Waiting for reply

@grayfurnaceman 5 жыл бұрын

The equalizing tube is there to account for any pressure drop between the TXV end of the coil and the outlet of the coil where the bulb is mounted. The sensing bulb controls how much the valve opens. GFM

@UltraHydrophobiccoat 4 жыл бұрын

Down stream means the direction of refrigerant flow? Away from evaporator ? Thank you

@grayfurnaceman 4 жыл бұрын

Yes. GFM

@frankmashione139 8 жыл бұрын

Is it possible to trick valves to open if the bulb blows its charge?

@grayfurnaceman 8 жыл бұрын

+Frank Machine Nothing that I would recommend. GFM

@OcRefrig 7 жыл бұрын

Yea, i heard a guy put a coin under the powerhead once till he could get back with a txv on monday.

@ryans450 6 жыл бұрын

If you do this, you are taking the risk of flooding your evaporator and damaging your compressor. If it were my own AC and I understood the risk, then maybe I would do this but I wouldn't do this to a customer's AC. You are on the hook for damaged components and your boss isn't going to be happy if anything happens.

$@grupinfractionalorganizatp5003$

@grupinfractionalorganizatp5003 5 жыл бұрын

hi -I don't understand 1-for the model T2/Te2 without third pipe from thermal expansion valve-when the valve are close the orifice -the presure wrere are going ? 2 the model with three pipe -third are conected at exhaust of evaporator -when the termic valve are close the pressure are going in bypass from third pipe ? And also who close the selunoid valve and the pressure of the compressor where are going ? the baypass are after this valve many thanks where I can find a animation of this ?

@grayfurnaceman 5 жыл бұрын

1. When the valve closes there is no gas passing from high side to low side. 2. When the valve has the equalizer tap, and the valve closes, there is no bypass from High side to low side. When the solenoid valve closes, the compressor continues to run until the low pressure switch opens the compressor circuit. The pressure made by the compressor continues to condense gas to liquid in the condenser. I have no idea on the animation. GFM

$@grupinfractionalorganizatp5003$

@grupinfractionalorganizatp5003 5 жыл бұрын

I don't understand, the pressure are go higher, no?

@grayfurnaceman 5 жыл бұрын

The pressure in the evaporator, in the off cycle, will raise to its saturated pressure/temp. GFM

$@grupinfractionalorganizatp5003$

@grupinfractionalorganizatp5003 5 жыл бұрын

I will ask again -pressure to out of compressor 14 bar - go to condenser after to filter and now passing through solenoid valve to expansion valve -----when close the selunoid the pressure 14 bar where go ?normaly are rise --the line have a expansion valve TE2 external egualizator -this egualizator when working if the selunoid are closed ? meny thanks

@chadlane5389 5 жыл бұрын

Great video! What did you use to cut the TXV?

@grayfurnaceman 5 жыл бұрын

Just a sawsall. GFM

@ryans450 6 жыл бұрын

Hey GFM. Where is the bleed port on these TXV's? Is it just a small hole between the suction and the liquid line?

@grayfurnaceman 6 жыл бұрын

I don't have any cutaways of a bleed TXV. It is just a small hole between liquid and suction. GFM

@teravolt6113 5 жыл бұрын

You can also set the bulb charge so that the pin never closes the valve completely and effectively acts as a bleed port, no need for one... employed in automotive TXVs, i've disassembled one of them and there's no bleed/bypass whatsoever, the pin perfectly closes the valve seat if i grab it with my fingers and try to close the seat with it, but when i reassemble the valve and freeze the power head with canned air, the valve still stays open a little... so complete valve closure can also be prevented by the bulb charge...

@earthsign28 4 жыл бұрын

What happens if you have a blocked equalization tube?

@grayfurnaceman 4 жыл бұрын

Superheat will be off by the pressure drop of the evap. GFM

@stephenhenry5346 4 ай бұрын

@@grayfurnaceman Does this answer mean an increase in superheat and starving the feed?

@nihaldominic5321 4 жыл бұрын

What is the use of equalizing line ??

@grayfurnaceman 4 жыл бұрын

The diaphragm that opens the valve is subject to bulb pressure sensed at the suction line. In addition, the evap pressure pushes on the diaphragm. There is a pressure drop between the entrance and exit of the evap coil. The equalizing tube compensates for that drop. GFM

@EightiesTV 8 жыл бұрын

I bet if you installed a sight glass on the equalization tube, you wouldn't see any liquid refrigerant whatsoever. Any miniscule amount that gets through those clearances is going to flash instantly once it hits the low pressure.

@grayfurnaceman 8 жыл бұрын

I thin you are right. GFM