Author Topic: Sensing Bulb Placement Question  (Read 2060 times)

Offline Porcupinepuffer

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Sensing Bulb Placement Question
« on: August 15, 2016, 08:02:11 AM »
Done several of jobs with these Aspen coils where it comes with the sensing bulb dangling in the box with the strap for the technician to mount. I'm curious about its proper mounting location as it seems difficult to mount it correctly to the way most literature states a sensing bulb is to be mounted in relation to the equalizer line.
The manual it comes with makes no mention of the equalizer line.  Everything I've read seems to imply you always install the bulb ahead of the equalizer line. On these coils, the equalizer line is literally mounted right beside the last manifold branch on the suction header. So there's not really any decent amount of room to install the bulb upstream of the equalizer line. It seems to install quite nicely on the center section, or with a bit of cutting of the strap it can be wrapped closer to the end of the header and still be upstream of the equalizer line.
If it cannot be installed on this header, it would have to be installed outside of the plenum on the suction line as there's not enough room after the equalizer line and the outlet of the suction line to connect it. Some other techs are installing it outside the plenum after their brazed joint.
I'm curious what you guys would do, or are doing. I'll post a picture from a thread on another forum where someone installed the bulb on the exact exact coil I'm referring too. However, the one in the picture was clearly installed by a buffoon that really had no idea what he was doing.

http://hvac-talk.com/vbb/showthread.php?1839261-Does-this-TXV-bulb-seam-at-the-wrong-place-to-you

Ohh, and on another note and word of caution. They leave these triangular shaped metal folds on the top of these coils on each end that are as sharp as a razor (also seen in the above picture). With my hand on top of the coil I naturally pulled my hand back after I was placing it and the sharp edge of this V shape metal sliced into my finger and only wedged in further and deeper as my hand pulled back. Excellent engineering design for getting cut pretty good.

Offline walker

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Re: Sensing Bulb Placement Question
« Reply #1 on: August 15, 2016, 11:08:26 AM »
the equalizer line will have no real effect on the bulb, try if possible to mount it horizontally after the equalizer, if you cant then vertical is fine too, on residential applications I have never seen any ill effects to mounting location as long as its strapped nice and tight and insulated.  The instructions for all the different brands of txv all suggest different mounting positions, so who knows which one is more correct.

Offline Admin

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Re: Sensing Bulb Placement Question
« Reply #2 on: August 15, 2016, 02:37:19 PM »
Pics attached.  The guide I have is in line with Walker says. 

Ever since the rust inhibitor problem with Copeland scroll compressors I no longer install TXV's.

Offline Porcupinepuffer

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Re: Sensing Bulb Placement Question
« Reply #3 on: August 15, 2016, 05:49:53 PM »
And there's an example of being told to put it downstream instead of upstream of the equalizer. I also notice the instructions for this aspen coil say to mount it at 4 o'clock and 8 o'clock, despite it being smaller than 7/8". All these differences make it tricky to remember correct answers on tests. In any case, I haven't seen any unusual behavior with the txv operation.

Offline walker

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Re: Sensing Bulb Placement Question
« Reply #4 on: August 16, 2016, 07:42:19 AM »
Pics attached.  The guide I have is in line with Walker says. 

Ever since the rust inhibitor problem with Copeland scroll compressors I no longer install TXV's.

still dealing with those units, changed another 2 just last week.  I've probably done over a 100 in the last 2 years.

Offline harshal

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Re: Sensing Bulb Placement Question
« Reply #5 on: August 16, 2016, 04:13:37 PM »
Did one today,re with pistons.