Thermal Expansion Valve Application 1

[rastus62]

I'm looking at a system overhaul and have been informed of alledged discrepancies from the OEM's original design that could look to be corrected at the same time.

Basically I'm interested in experience of TX valves used in tandem (controlled via solenoid valves) to give the ability of using all of the evaporator through both TX valves or just half (in higher ambients) using just one TX valve.
The models currently used are Danfoss with external equalisation, which is where the 'advise' comes from - do the external equalisation lines from the separate TX valves need to be connected together as well as after the evaporator?

Many thanks

Joe

 

[MintJulep]

The external equalizer lines simply need to have access to the suction side of the evaporator.

You could connecte them together first, then make one tap to the suction line, or connect them independantly to the suction line. Should make no difference in performance.

 

[imok2]

As I understand it you’re saying that you are going to stage the cooling effect by using two X-valves. If so you need to have two separate cooling coils each with its own TXV and each coil will have its own external equalizer. So whether your designing face split, row split or interlaced coils each coil has to have its own connection of external equalizer to one TXV

You can't have one cooling coil with two TXVs and expect the coil to operate with one on and one off when the load drops. If this can be done with new technology then it's something I'm not aware of.

 

[DrRTU]

Review the Sporlan booklet on TXV application. Connect both lines together then to the correct spot on the suction line.

http://www.sporlan.com/10-9.pdf

Page 11 shows a dwg. with 1 and 2 evaporators.

 

[MintJulep]

Yeah, my understanding was the same as imok's. Split coil, eventually plumbed back to the same suction.

 

[imok2]

Thanks RTU I always like it when I learn something new so for above and beyound I recommend you for the star :>)