Trouble shooting tx valves

[TECH TIM]

This may be a silly q but i have recently started working in commercial refrigeration and am wonder if any one has any helpful info on trouble shootin tx valves, i have a few systems running with full sight glasses and still not floodin evap correctly not sure if i may have restriction or if orifice needs changing or even checking and adjusting super heats i have many years expirence in domestic refrigeration and whitegoods so if any q's on these dont hesitate also ill be askin on pressure controls soon but more interested in txv's at moment thanks guys hope to chat about things soon :o

[nike123]

http://www.refrigeration-engineer.com/forums/showthread.php?t=11903&highlight=adjust
http://ra.danfoss.com/TechnicalInfo/literature/manuals/01/PF000G102_chapter_01.pdf
http://ra.danfoss.com/TechnicalInfo/literature/manuals/01/PF000G102_chapter_10.pdf
http://www.achrnews.com/Articles/Service_and_Maintenance/82e2faf38c67a010VgnVCM100000f932a8c0____
http://www.mediafire.com/?nitrjmtxycz
http://www.intkorea.kr/data/sporlan/10-11.pdf

[Gary]

This may be a silly q but i have recently started working in commercial refrigeration and am wonder if any one has any helpful info on trouble shootin tx valves, i have a few systems running with full sight glasses and still not floodin evap correctly not sure if i may have restriction or if orifice needs changing or even checking and adjusting super heats i have many years expirence in domestic refrigeration and whitegoods so if any q's on these dont hesitate also ill be askin on pressure controls soon but more interested in txv's at moment thanks guys hope to chat about things soon :o

Not unlike a domestic fridge, the evaporator is fully flooded ONLY when the refrigerated space is down to design temperature. When the refrigerated space is warm, the superheat is supposed to be high.

[abet_meneses]

tech tim,

what is the application,btuh rating of equipment,system pressure and txv rating?

regards,

[TECH TIM]

Thank for links very helpful

[TECH TIM]

Thanks Gary for your reply that has seemed to be the case after running 24hr or so evap seem alot better thanks again

[TECH TIM]

not real sure on tech specs i have been workin on various displays and drink fridges mainly, most jobs have been compressor changes but i havnt had much to do with tx valves etc and have noted coils flood differently to domestics wich is my forte... im wanting to leave that behind and move on to commercial/ industrial all in good time i guess thanks for your replie

[US Iceman]

Direct expansion evaporators are NEVER flooded (on purpose).

The inside of the evaporator coil will have approx. 80-85% of it's internal area wetted by liquid refrigerant. The last 15-20% of the coil surface area is used for superheating the refrigerant vapor.

If you start a system up warm, the superheat will be higher than normal. Do not adjust the TXV during this time.

Wait until the temperatures are down to the expected range and then check the superheat.

[raz5]

excellent posts with links thanks guys helped me work out why my 404 walkin freezer isnt getting the right superheat after compressor and evep change :D:cool:

[unicorn77]

its very wrong and sily to adjust the txv. the txv is pre-set by the factory
now you have big problem you compressor will damage and txv need to replace good luck

[monkey spanners]

its very wrong and sily to adjust the txv. the txv is pre-set by the factory
now you have big problem you compressor will damage and txv need to replace good luck

You can always adjust the valve back to how it should be set, so long as it is not faulty.

[james10]

You can always adjust the valve back to how it should be set, so long as it is not faulty.
Good point if i ever adjust a txv i always count the number of turns to try and make sure the setting is returned to it's original position