whats up with that?

[coolerboy]

hey all, first off....im coolerboy and its just grand to be here -*chuckle*-

so yar..i need a bit of input...
about a week ago this supra 822 shows up on my doorstep with a burnt interface board (its the microprocessor model), after giving the unit a thorrough checkup i started to repair the thing but to no avail....all my efforts were in vain....u see, i have decent headpressure as well as 26 psig suction, i changed the expansion valve orrifice as well as the two valveplates, gave it a compressor oil change and a new drier. vacumed it for aproxx 13 hours and gave it a fresh charge. my expansion valve is responsive and all my other components are working fine yet i have NO cooling whatsoever. 0 degrees temp difference.....as far as im concerned the unit should be cooling but here i sit. any ideas?

thnx for a great site.

[NoNickName]

liquid temperature? SH, SC?

[coolerboy]

i checked the suction superheat and to my surprise found that i only have 3 degrees..... but i am now very close to setting the thing alight. started it this mornig and my head pressure went straight for 400 psig!! it was fine yesterday. tried a reciever pump down... no luck either. one of the guys at carrier suggested the check valve on the reciever tank might be leaking but i checked it and its fine. still doesnt explain the hp problem. its the first time since ive been doing this trade that a machine has given me this many problems and headaches.

thnx for the input nonickname, its appreciated.

well...let me go and see if i can convince my customer to buy a oily rag, bottle of gas and a box of matches.

ciao

[clivemtk]

are all evap fans working

[coolerboy]

yep, all of them.... that was part of the initial problems on the unit. some idiot modified some transfrig fan motors to run on the carrier but the fan spiders he used were too light so one broke and the fan jammed into the evap housing, and he also had 40 A fuses for the fans...end result.... burnt interface board.

ive considerred replacing the entire expansion valve, altho its responding. think it might work?

[The MG Pony]

I would start at the core basics. Is every thing clean with good air volume flowing through it? Are all the mechanics solid and operating smoothly together? Does the TXV have solid feed back from the pipe? Is the EQ line free of any blockages and dents? Are all pipes routed straight as possible with no dents or sever bends?
are the evap fins straight and not gnarled?

Things like this, I find, tend to resolve the issues that can arrise in large or small systems.

[coolerboy]

the evap is clean and the fins are all open...no restrictions on the airflow part. txv is getting a good feed from the pipe and is responsive. my pipes are all good......but one thing that still baffles me is why th headpressure suddenly decided to shoot up to 400 psig, when the day before i had about 250 psig.

heres exactly what i did: first i replaced the interface board, then i had to replace al three fans and spiders, new drier, new txv orrifice, new valveplates on the compressor, comp oil change, decent vacuum and a fresh charge of gas.....

everything is working..yet no cooling hence my problem...and now im battling with headpressure yet we are at aproxx 15 dgree ambient temp.

[chillin out]

Sounds like you have left a cap in the drier or something.

Restriction in the circuit for sure.

Chillin

[The Viking]

One of the fans going backwards?

[lana]

Hi everybody,

There is HIGH PRESSURE problem, why are you looking for TEV or restriction in the liquid line?
If you have TEV problem or pre-expansion you will get LOW suction pressure.

High discharge pressure is due to :
1- Excess refrigerant.
2- Non-condensible present.
3- Lack of condenser capacity.

The first two faults make the sub-cooling to increase, and the third makes the sub-cooling to decrease.
Also note that the first two (above) have the exact symptoms. You have to do a non-condensible test to find out which one it is.
SO it is a fairly simple fault to diagnose, except there is more than one problem there.

Good Luck
Cheers

[mohamed khamis]

the evap is clean and the fins are all open...no restrictions on the airflow part. txv is getting a good feed from the pipe and is responsive. my pipes are all good......but one thing that still baffles me is why th headpressure suddenly decided to shoot up to 400 psig, when the day before i had about 250 psig.

heres exactly what i did: first i replaced the interface board, then i had to replace al three fans and spiders, new drier, new txv orrifice, new valveplates on the compressor, comp oil change, decent vacuum and a fresh charge of gas.....

everything is working..yet no cooling hence my problem...and now im battling with headpressure yet we are at aproxx 15 dgree ambient temp.

Hi coolerboy

Well...Have u checked the discharge air from the condenser....it may be recirculated or diverted again to the condenser (due to some barriers) and causes the head pressure to raise up and inefficient condenser performance. Otherwise the condenser size or the fan size is smaller than required. That can cause the same symptom.

best regards

[coolerboy]

well, i guess im really gonna luff it here, as was said earlier..."back to basics"....

i found the problem this afternoon when i tried to recover the refrigerant and my recovery machine didnt want to remove any liquid from the system. seems what happened is, with the vacuum, carbon kept the expansion valve in the closed position causing the evap section to stay full of oil and refrigerant (dont we all just say thank you to refrigeration butchers) so when i charged it, the remaining refrigerant in the oil caused an overgcharge. so much for a responsive expansion valve.

now im just waiting for parts and then we all systems go

thnx for al the help, its really appreciated

ciao

[coolerboy]

just a little something i want to share with you guys.... the first is a picture of a sieve that is found under the suction service valve on a carrier O5K4 compressor... u will see two sieves, the one on the left is only used for comparitive reasons, the righthand one is the one i took out.

the second picture is of the sieve in the sump of the same compressor.

ciao

[The Viking]

Ooops,

Someone been brazing without OFN???

[marc5180]

naughty naughty.... many people that i have come across dont seem to use OFN when installing a system even thought id imagine they know they should

[airconadam]

yes and so many people cool it down by them sleves and not naturally with ofn still running through

adam

[coolerboy]

hehe, i dont know what the hel they did. but yar.

on another topic.....
i almost died on friday night!!! went out on a breakdown in kimberley and was standing next to the truck busy with the feul system, when some *very naughty word* aimed right at me with his car!!!!!! hehe, never knew i could jump so high. any of you ever experience the same thing?

ciao

[airconadam]

no and dont want to either

adam