compressor sizing?

[Northdude]

Hi guys, a customer of mine has just taken over new premises which has a coldroom. Whoever the last guy was using he must have been one hell of a cowboy as there were bare wires everywhere and lots were burnt out etc. The guy told him it was a freezer, its integral where the evap and condensor is all one. Problem is it wont pull down past minus 8 degrees, the compressor has been changed and its one of the roughest jobs i have ever seen. I am not convinced it is even a freezer and maybe a chiller as i cant see a door frame heater, if it is a freezer then the compressor must be undersized as gas charge, defrosts etc (i have re-wired everything) are all fine. The orignal controller had been changed so i cannot check the orignal setpoint.
The condensor is a Criocabin, mod - LM06BT
The orignal compressor was a MS26FB, R404A

The compressor currently installed is a Danfoss ??15CL on R404A (the start of the data plate is ripped off but im guessing its SC15CL.
Just wondering if anyone can shed any light on whether it is a freezer or a fridge/chiller and whether the compressor is indeed undersized, Thanks in advance!!

[install monkey]

is there a defrost heater in the evap coil? a drain heater in the drain to the condenser section? did the fans stop during defrost- if so its a freezer,otherwise its a fridge- not much info on criocabins website

[knighty]

original compressor date sheet
http://www.hawco.co.uk/UserFiles/Products/Files/MS26FBT061UFCSR.pdf

new compressor data sheet
http://de.refrignet.danfoss.com/TechnicalInfo/Literature/Manuals/06/SC1515CL_R404A-R507_220V_50Hz_08-02_Cf54h202.pdf

info about the cold rooms the company makes...
http://www.criocabin.com/uploads/pics/Easy_2010_Light_29.PDF


what size is the room, so the heat load on the compressor can be checked ?

I'm not a fridgie, but it looks to me like the capacity of the original compressor was 700 to 1000 kcal/hour and the new one is about 1500 to 1800 kcal/hour ?

hope this info helps :-)

[install monkey]

looks like a freezer application going off them data sheets, low back pressure r404a

[Northdude]

hi, the defrost is hot gas and i cant remember seeing a drain heater? (i dont think there was one but whoever had been working on it could have ripped it out and not bothered to replace it as the whole thing was a mess) the controller which was on it was blank and completley battered so i replaced it with an id freeze but the fans will stop if its a fridge or a freezer as its on hot gas.

[Northdude]

Is compressor undersized?

[install monkey]

what pressures/temps are u getting, is the hot gas valve passing? is tev set correctly gas charge correct,compressor pumping efficiently?? was the drier changed, is there a temp difference between the inlet /outlet,cond coil clear of dust/grease

[Northdude]

missed your post knighty just wondering if SC is the start of the code?

[Northdude]

At minus 8 suction is between 15 and 20 psi, ambient is around 20 degrees c, no tev its capillary, cond coil is clear, suction sweating, hot gas solenoid not passing and compressor is pumping correctly, will need to call back to job to get more info

[install monkey]

dean-wood.com/downloads/dean-wood/?aid=913&pid=1046
bottom of page 11 shows nomenclemature- how long was the freezer running for-could take a while to get colder,check door seal is good,as for no door heaters this may be a problem, check gas charge and compare to the nameplate if its still there, test td accross coils (air on/off)

[Northdude]

thanks for the posts, as long as i know the compressor can do the job i will call back and spend a bit of time on it and get it down to temperature, was just convinced it was the wrong compressor, thanks again!!