404 freezer wont go all the way down

[cold viking]

im from norway ,pronounces english like an mental nutcase.

i have a never ending history with an accona freezer bench.customer claims the temperature isnt low enough only -13 celsius he wont -18. set temp is -22
.system is ,404a 1000gram ,danfoss sc12,te2 00 orfice .compressor and condenser is supposed to be in the funiture(bench) but is moved out to other room 27celsius ambient .7meter tubing 1/4" 3/8".it has a reciever as well.

first time suction pressure seemed high 1.8 bar gauge.and tev didnt compensate .called my refrigerant supplier, he recommended me to change tev and orfice .at that moment i didnt know it was fitted with orfice 00 (not sure if that is original)so when i told him compressor size and desired cabinet temp he suggested the 0x orfice .

after replaced tev and orfice 0x temp stay the same .but suction pressure is 1 bar gauge .the i have may overlooked is the condensing temp in the middle of the condenser pipetemp is 27celcius and headpressure is 12,5 bar (after reciever) and head pressure goes down when temp goes down in cabinet.sightglass is full and clean but liquidline is "cold" maybe 20 celcius

btw compressor is replaced filterdrier and burnout filter. flushed with nitro and in a long vacum

could the 0x orfice be to small to this evap ,no heat to reject or maybe condenser fit better ambients in the bench

or does it need exorcism?

[Gary]

If the ambient is 27C, then the liquid line cannot be 20C, unless there is a restriction between the condenser and the point where you determined that the line was 20C.

But then, we don't know if the line was 20C, because that was just a guess.

If we are going to help you, we don't need guesses or opinions, we need real temperature and pressure measurements.

[Gary]

Start here:

http://www.refrigeration-engineer.co...ad.php?t=19701

[cold viking]

If the ambient is 27C, then the liquid line cannot be 20C, unless there is a restriction between the condenser and the point where you determined that the line was 20C.

But then, we don't know if the line was 20C, because that was just a guess.

If we are going to help you, we don't need guesses or opinions, we need real temperature and pressure measurements.

ok i agree with you that maybees wont go anyway .but if i ask you what can cause an not warm liquid line and low head .as long as compresor is new and i have charged gas with weight and 50gram additional for tubing 7m

[Gary]

If the system absorbs little heat from the evaporator, then it has little heat to reject in the condenser.

[Gary]

If the system has the proper charge and the new TXV is properly sized, but the coil is starved, then there must be a liquid line restriction (or plugged coil inlet/distributor/equalizer line). Did you replace the drier? Is the TXV externally equalized?

[cold viking]

If the system has the proper charge and the new TXV is properly sized, but the coil is starved, then there must be a liquid line restriction (or plugged coil inlet/distributor/equalizer line). Did you replace the drier? Is the TXV externally equalized?

i replaced the drier , the txv is not externally equalized .the coil could defently be starved due to the smaller orfice .since compressor is moved i added 40gram for the 7metres longer piping. it has reciever
just added charge to have it close as possible to original spec.superheat spindle is all out and 3 turns in that should be factory setting.are going to measure superheat and subcooling

if we assume that 0x is to small for evap and i swith to 00 orfice could that possibly raise my head enough

[Gary]

Before I made any judgements about the system, I would get a full and accurate list of temperatures and pressures.

Evap air in temp
Evap air out temp
Low side pressure or saturation temp
Suction line temp at evap outlet

Cond air in temp
Cond air out temp
High side pressure or saturation temp
Liquid line temp at receiver or condenser outlet

[RefrigNoob]

Gary is right as always. Full set of readings.

But with my limited experience I'd say that the orifice is way too small. LP at -30degC with a cabinet at -13degC. The original figure of 1.8bar LP was much closer.

But listen to Gary, he really knows his stuff.

[R. skiffington]

If you know the details of the compressor then you need to find out it's capacity and then determine your orifice size, the scale is on the inside of the danfos txv box, once you know you have the right valve and orifice, then you can start looking at your pressures, no point guessing. Like Gary said, the condenser will only start working if the evap is working. SOunds like a case of just getting back to basics. (An MOP valve hasn't been installed by mistake has it, i've seen that before)

[philfridge]

just added charge to have it close as possible to original spec.superheat spindle is all out and 3 turns in that should be factory setting.

This is incorrect setting turn adjusting screw fully clockwise then out 2 1/2 turns anticlockwise this is factory setting. You should not mess about with the tev adjustment screw it is rarely required.