cap. tube to TXV

[jackal]

I worked on a 2 door Jordan 40 cubic freezer the other day with a split, 2-cap tube coil that had both sides of the evaporator completely frosted. I checked the paragon time clock and saw the motor was not turning.

Obvious problem, so I replaced time clock with a Grasslin and went on my way.

The next day I get a call and the guy says the freezer is only at 30 degrees F. I went and checked and one of the cap. tubes must have been restricted because only one of the two coils had frost on it. I cut out the first two inches of both cap tubes, replaced drier, pulled deep vacuum and recharged with new R-404A. Still no luck, only this time the other coil wouldn't develop frost! Must be junk floating around the system was my thinking.

So, I pulled both cap. tubes, and installed a TXV, sight glass and drier. Charged to a full sight glass and found the freezer is working much better, but one of the coils looks a little starved as it only frosts for about 3/4 of the coil. The other coil has a full frost pattern.

So my thought is perhaps when I brought two 1/4 tubes and joined them together at the TXV outlet, one tube is getting more refrigerant than the other. I did put an externally equalized TXV with the equalization port properly connected to the suction line, but factory coils with more than one circuit have that little disc rated for different refrigerants...so maybe that helps equalize the refrigerant in both coils?

How do you guys go about installing a TXV in place of a cap tube system when there is more than one cap tube.

Thanks.

[nate1701]

which coil is the Txv bulb sensing or is it on a common suction line?

I would think with flashing at txv outlet the turbulence might not feed refrigerant evenly to both lines... add to that subtle differences in the inlet/outlet of evap piping.

It might be more accurate to tee off two txv's from the liquid line and each coil is metered independantly. With a soild column of liquid to each Txv you will have proper feed and super heat in each evap.

did you mention a receiver was installed?

[Joe Harper]

Install 2 txv's.
It is more expensive than using one, or replaceing the cap tubes. You just have to explain to the customer that they wont have tube problem's anymore. If they have more than one reach-in they will probably be more than happy to pay for the conversion.

[nate1701]

actually I re-read your post and realized it's not two evap's but I would think that without a proper distributor the same principles apply.

someone with more experience in this situation might have more insight.

[Joe Harper]

I read this as having two coils. Each coil needs to have its own metering device. If the coils are together, plan on parking yourself for a while to get them adjusted properly..

[selfemployed]

If you need a Jordan/Folger coil for a 2 dr. refrig. have a new one still in the box. Split coil where fan is in the center.

[jackal]

Thanks for the insight from all of you. This conversion does include a receiver and it is one evaporator with two coils. The original setup had two cap tubes feeding the coils so I thought one TXV would work ok and it does, sort of except the one coil does not have a complete frost covering. The freezer does go down to the 5 degree range, but according to the owner, it used to be around zero.
So it sounds like two seperate TXV's may be the way to go.

[Phase Loss]

it is one evaporator with two coils.

:confused::confused::confused::confused::confused:

If you have 2 evaporators, you need 2 TEV.

If you have 1 dual circuit evaporator, you need 1 TEV with a distributor nozzle.

[jackal]

I have a dual circuit evaporator with a home-made distributor--perhaps the weak link in my repair.

The factory dual circuit evaporators often have that disc or orifice plate often rated for the various refrigerants. Do you think that would be necessary as well?

[Phase Loss]

yes i think a distributor is required on any multi-circuit evaporator along with an equalizer line on the TEV.

[jhd1234]

http://sporlan.jandrewschoen.com/20-10_062009.pdf

http://sporlan.jandrewschoen.com/20-148.pdf

The first time I got an education about distrbutors was on a 7.5 ton split where someone had made a home brewed distributor. The system hadn't cooled right for years. When I saw the mickey mouse job that had been done, I figured it was the problem but I didn't know how to fix it. Bulletin 20-10 was aa real education for me. Bulletin 20-148 is a new one on me. I had no idea you could get pre-brazed assemblies from Sporlan.