Advice needed

[stevespeed]

Hello,

I was recently asked by a friend to carry out repairs to freezer in an ice cream van that was over 30 years old.
The freezer (230v)plugged in to mains at shows etc,is just a chest like freezer of just under 1 meter squared.I didnt really want to get involved but unfortunatally for me I did.

The compressor was Lunite CAJ4461A (R12),the condensor is very accesible but the cabinet is completally buit in when the van was manufactured and there is no way to acces the evaporator or capilliary tube.I replaced the compressor with the equivalent accept on R134A.

The freezer reaches -22 centigrade which I thought under the circumstances was pretty good.Unfortunatally the customer is not happy with this and saying that they previously reached -29 centigrade and require the same temperature as they need to keep things frozen between there journeys(ie hooking up to mains)

I have suggested getting a 230v permanently in the vehicle but they want the freezer to perform as good as it did on R12.

Any suggestions would be welcome.

Should I replace the compressor with another using R404A or could I use an alternative refrigerant with better performance.I cannot acces the capilliary tube to make any alterations.

Cheers,
Steve

[install monkey]

is it cutting out on stat, if so link it out or adjust it for -30, or get a 12v-240v inverter rated at 2kw will cost him around £250 - his choice, in the meantime,dont buy a cornetto:D

[Teuria]

Hi

Is there enough refrigerant?

What is evaporating temp or pressure, condensing temp / pressure and suctionline temp?

Is compressor running all the time?

And last but not least, why did you change old compressor? old broken? :D

[charlie patt]

the bunkers on they should reach minus 30 easily sometimes there is no stat on them just a lp switch so it may be a case if you running on r134a the lp is tripping you need to run it overnight and check it in the morn the cabs have that much insulation they are meant to run all day without running again does unit have a chiller unit for cold drinks as well useually one comp feeds two bunkers one freezer and one fridge if chiller set to cold its pinching the freezer temp when i change a comp of a 12 unit i change the condensor both tevs and put on 404a

[stevespeed]

Hi,yes it wont reach the setpoint on the stat -30.
Wish they would go for an inverter .
Cheers

[stevespeed]

Hi

Is there enough refrigerant?

What is evaporating temp or pressure, condensing temp / pressure and suctionline temp?

Is compressor running all the time?

And last but not least, why did you change old compressor? old broken? :D

Hello mate,yeah that is a good point,I changed the compressor as the old one was siezed.I dont quite remember the exact presures to be honest.As it was a cap system and no info on how much refrigerant quantity I charged old school very slowly untill I just started to frost back on suction.Did not stay with unit till it reached -22,as it takes upto 24hours to reach max temp.

[chillerman2006]

stick the temp probe on evap inlet & give him minus 30 or below ;) [oops did i say that out loud]

R's chillerman

[stevespeed]

Hi thanks for your reply,
It is only the one (bunker ?)freezer with no fridge and no LP,just a stat.I was considering going to r404a but need advice on what size compressor,remember its a cp tube system and I cant access the tube to make any alterations without prctically disasembling the van :).I need to know if an equivelant hp compressor on R404A would do the trick.Experience tells me it wont be that simple for many reasons,I think I would have to replace the whole condensor which is fairly simple,but the cap tube would surelly need altering if not replacing ?

[chillerman2006]

cap tube system are specific charge, so would expect flow rates to be well out going from R12 to R404a

Isceon 49 was a drop in for R12 but recall using it nearly 2 decades ago and was ok as chiller but at lower temps there was issues with oil return

not sure whats available these days for drop in as have not seen anything but 400 series refrigeration systems in many years.... climate/hrp would be able to give you list of available gases though along with there intended use/oil compatabillity

R's chillerman

[Teuria]

Hello mate,yeah that is a good point,I changed the compressor as the old one was siezed.I dont quite remember the exact presures to be honest.As it was a cap system and no info on how much refrigerant quantity I charged old school very slowly untill I just started to frost back on suction.Did not stay with unit till it reached -22,as it takes upto 24hours to reach max temp.

Hi

Maybe you should check pressures and temps? at least from suction side.

Then we know what's happening.