Help! 20-ton Trane liquid line pressure loss

[tracdan]

I am trying to start up a 20-ton straight cool condenser sitting on the ground. The heat exchanger is 3 stories up (125 ft line set and 5/8 liquid line). The unit has thermostatic expansion valve. The liquid line at the condenser is 255 psi and the liquid line at the heat exchanger is 205 psi. What could be causing the pressure loss? There is no filter.

[local 832s]

The 3 story run of the liquid line??

[powerhead]

5/8 liquid line at 125 ft of linear run is too small for R22.

What is your equivocal length?

[Pneuma]

You need to look at the install manual and make sure you follow the long line guidelnes. You can also get a hold of the manufacturer either at your local sales office or the factory technical guys. You should make a drawing of what you have, get a fitting count and note if the 90's are long radius or not.

You will probably be required to have several accessoires, such as an inverted trap at the top of the suction line, a hard start kit, hard shut off txv, crank case heater. You may find out you have exceeded the capabilities of the system. They typically don't want you upsizing the liquid line.

The pressure drop is due to the length of the line. Inevitably when you have along run your system capacity is reduced and it's worse when you pump liquid uphill. Probably from 3-5%.

Talk to the manufacturer and Good luck!

[stanbyyourword]

perfect light commercial application for liquid pressure amplification (hy|save ), pump the liquid over/up high lift and possibly float head pressures saving energy , regards stan

[tracdan]

Thanks. The liquid line length isn't negotiable. The freon is R407C not R22. I didn't mention this before. I also did more checking today and I got a 9 degree subcool at the condenser. Any more suggestions?
For Stan, I don't know what you mean by your response, could you provide some additional details?

[Freezeking2000]

perfect light commercial application for liquid pressure amplification (hy|save ), pump the liquid over/up high lift and possibly float head pressures saving energy , regards stan

Great energy saver and it should help with the liquid drop.

[tracdan]

I didn't get what Stan was saying in his reply. Could you provide more information on this?

[jayguy]

Thanks. The liquid line length isn't negotiable....

it will be negotiable if the unit can not work properly or is too maintenance intensive or the failure rate becomes too high.

how much steam do you lose when you run up 3 stories...pressure drop is going to be the same...when you run it uphill, it loses pressure. your pressure drop may be normal, but is it acceptable?

too small of a liquid line and you have large pressure drops...too large of a line and you hold too much refrigerant and oil. you need a happy medium and that may mean relocating the unit.

like Pneuma said, get the local office involved and get them to bless it with Trane's holy water that way you are covered.

good luck.

[phoenixfitter]

What model Condensing unit is it? Is it a scroll compressor?

[tracdan]

It's a dual scroll compressor. I will check the exact model today.

[stanbyyourword]

http://www.hysave.com/technology/ref...t_pumping.html lots of info here and contact, hysave pumps are a refrigerant liquid delivery pump, used primarely in refrigeration as pressure subcoolers and floating head pressure technology whilst supplying 100% column of liquid to txv over long runs, i will try to post a pic of a large condensor on the ground with no NPSH /gravity to feed the pump , what is used in this app. is an inverted "dropleg" oversized usually at 2" x 24" high to maintain gravity /column to inlet , and away you go regards stan

[stanbyyourword]