How to mount the TXV bulb on the air conditioner
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- Опубликовано: 12 сен 2024
- This one covers the do and don'ts of bulb installation. 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.
You have the best videos, you always cover the intricate details of the topic and knuckleheads like me really appreciate it. The one item you could have covered was mounting the sense bulb internal or external to the evap cabinet, I've heard that it should go in the cabinet if it will fit. The vapor line on my unit is vertical, it exits the cabinet and goes straight up so I'm glad you covered the orientation of the capilary tubes for vertical mounting. Thanks and keep up the good work !!!
Great video. I was told by a manufacturer that piping smaller than 5/8 could make some contact with the oil and liquid at the 3-4 or 8-9 position. GFM is right on the money again with great advice.
hey gray,was scratching my head yesterday,i had 2 lennox units a 1 1/2 and 3 ton,same home,1 for a FROG and other to the house,both AH coils frozen over,both units after thawing out had identical pressures,r22 25psig low side,165 high side,75* indoor and 85* outdoor temps,i evac the 3ton on a scale, charge was spot on,at the AH can tell at one time someone brazed txv's on both units,crappy job,burn marks everywhere,i figured they destroyed them on install,was waiting on approval to proceed with repairs,when i saw this video i remembered the bulbs mounted vertically and the lines on the bottom,i will run over there, flip a bulb,check pressures and see what happens,and let you you know
I would like to hear.
GFM
Did it work
I have gained a great deal of insight from your videos. Thanks for taking the time to share the knowledge.
Welcome
GFM
Great information GFM. Very well explained as always.!!! Now I'm more comfortable as to where and how the bulb is mounted. Thanks:).
I feel awesome now, I mount it the same way you teach it.. Glad to see I know what I am doing.. Sometimes I wondered... Thank you so much for the videos...
Thanks for the video I’m a apprentice and learning a lot
Thanks GFM very nice explanation, Glad you still sharing the knowledge.
Does it matter which way the bulb faces on horizontal? Could it face the coil instead of facing towards the filter dryer
It makes no difference.
GFM
@@grayfurnaceman thank you
Great video
Good video. Please, correct me if I'm wrong, but you didn't say anything about bulb when it is installed horizontally (even in the video you placed the wrong way). When it is horizontally, you should keep the short capillary down and the large capillary up, so you'll keep the liquid inside the bulb instead of it going through the capillary. Thanks in advance from Venezuela.
I can't say I have heard that one. I any case, the liquid will stay in the bulb as the temp of the bulb is lower than the ambient.
GFM
How about mentioning mounting location as it relates to the evap and equalizer
bfxp63 I will be dealing with that soon.
GFM
Great video very much appreciated
Well Thankyou much. I have noticed sometime the txvs are completely inside the unit, and sometimes are exterior. I will continue my practice of using a camera or removing sheet metal to see. On another note, I bought a field piece charging jacket so I can accurately charge a txv in cooler temps. Question is why can I not use that same jacket for a fixed orfice? We are trying to get some of these tune ups done now in spring before it gets hot and our scheduling gets busy.
+Aaron Stokes Low ambient charging is never as good as charging under actual load. I have blocked condensers for many years whether it had a TXV or fixed orifice. You might not catch a small undercharge on a fixed orifice system, but it is the best choice you have for the system.
GFM
@@grayfurnaceman p
Hi GFM, I was wondering if you know around what year the industry started using TXV'S?
I was just curious on the history. Thanks
I would like more explanation on where to place the bulb in relation to the equalization tube. Before or after?
+trackontube The equalization tube should be placed just downstream of the bulb. It sometimes will pass a small amount of liquid refrigerant thru the tube that would upset the sensing of the bulb.
GFM
good learning video, Thanks
Question for you I am struggling with. I get asked frequently to "do a tune up" on ac, heat pumps for residential. Part of this service is checking the charge, and checking the charge I will need to know if I have a TXV or a fixed orafice. My question is this. How can I tell if my indoor coil has an TXV or a fixed office. Do I need to every time pull sheet metal off of the A coil to physically see if I have a TXV/fixed office?
+Aaron Stokes That's pretty much it. Trade has some models that tell if it has a TXV, but if the installer did not change the coil with a replacement outdoor unit, you still may not know. One possible way would be to shut down the unit and watch the gauges. If it equalizes fast, it has a fixed orifice Hope this helps.
GFM
If the vapor line pressure does not change significantly while charging the system, you likely have a TXV, the better way is still to look for it.
Thanks. After 3 years with new system I peeked in my attic on my trane unit and it was mounted vertically on suction line outside of evap housing. Problem was, it was hanging suspended 2” away from pipe in mid-air and must have slipped out of bracket. I stuck it back in and insulated it. My ac seemed to work over the years. What did this affect?
There was some efficiency loss and possibly some damage from refrigerant flooding back to the compressor.
GFM
I was told on 7/8" or smaller it's at 2:00 or 10:00. If it's above 7/8" it sits at 12:00
Wayne Hensley The info I used is from Alco and they use the 4 and 8 o'clock positions. Actually I would guess there would be little difference in performance.
GFM
So on a new coil install, you would braze the lineset on first...then attach the txv bulb?
Absolutely. The brazing temp could damage the bulb.
GFM
Add a little thermal paste too the bulb
Thermal paste has not been commonly used for TXV bulbs, but I would not argue with using it.
GFM
@@grayfurnaceman You are correct all it does is enhance heat transfer.It is very rear to see it because it's not a requirement.Danfoss will say if its available you can use it all it does is help it enhance heat transfer.
why not 12 o clock on all sizes? whats the difference gonna be from 10-2 versus 12? just curious?
awsom70 I think the temp on top of the pipe is a little higher than lower on the perimeter.
GFM
The bottom is likely to carry liquid if the evaporator is flooded during certain transitions, so the bulb will pick up that temp and adjust accordingly to prevent liquid in that line.
Cork Insulation Tape or Foam Insulation Tape. Also, I am not a tech but the tape is falling off of the bulb can I do this.
I don't see why not.
GFM
Does the tail end go up or down on a horizontal 3/4 suction line?
Does not make any difference.
GFM
I have a question, my furnace currently doesn't have a thermostat, instead I have to open the control access panel at the bottom of the furnace and find a know that has Lo 1 through 9 and Hi. The furnace came with directions and in the directions it say that there is a sensing bulb. Does this sensing bulb automatically shut of my furnace once it gets to hot? I notice that sometime when I leave on the furnace it automatically shuts off. I typically don't have it on for extended period of time since I'm worry it might over heat. sorry for my ignorance on this topic.
+Mostly Drew The sensing bulb acts as a thermostat. It should not overheat. Hope this helps.
GFM
+grayfurnaceman awesome. This helps a lot. Its funny, the guy from the local gas company who lit the pilot light for me said I could only turn it off and on He also told me to not have it on for extended periods of time as it will get to hot and cause a fire. I knew that didn't make since as it's not an old furnace. Plus it would turn off by it's self every once in awhile. Good thing I found the manual to it near the doors its located by. Thanks!
+Mostly Drew Unless it is covered in flammable materials or has a gasoline can set next to it, I don't think it will start a fire.
GFM
+grayfurnaceman ha-ha no none of those are near the furnace. that's again haha
I did put one the wrong way. It does not work.
Wher can you buy those clips for the TXV bulb
As far as I know, the are factory parts.
GFM
Can an txv be install outside the case coil
Yes, and it commonly is. It should be insulated also.
GFM
I have an 4 ton Lennox LRP14HP unit that the sensing bulb's cap tube broke. Does anyone knows how to repair it? or do I need to change the whole TXV? Thanks!
It cannot be repaired. If the head can be removed, you can replace it. In most cases, the entire valve must be replaced.
GFM