Walk-in Cooler Help Please

[crazy eye]

got a call on a walk in cooler not keeping temp. R22 unit , condenser on roof ,low 62 psi , high 360 psi ,hose down cond coil ,check fan motor ,blade rotation ,still the same . Could be non-condensible in system . Pulled charge ,replace dryer ,vacuum to 250 mircon ,charge unit and still the same .

ODT 109
low 62 psi
high 360 psi
discharge line temp 235
liquid line temp 125
suction line temp 62
cond enter air temp 109
cond discharge air temp 129

low pressure on evp. 62 psi
suction line temp after evp 49
box temp 45
Any suggestions

Thanks

[jpsmith1cm]

undersize?

[sarpanch2001]

got a call on a walk in cooler not keeping temp. R22 unit , condenser on roof ,low 62 psi , high 360 psi ,hose down cond coil ,check fan motor ,blade rotation ,still the same . Could be non-condensible in system . Pulled charge ,replace dryer ,vacuum to 250 mircon ,charge unit and still the same .

ODT 109
low 62 psi
high 360 psi
discharge line temp 235
liquid line temp 125
suction line temp 62
cond enter air temp 109
cond discharge air temp 129

low pressure on evp. 62 psi
suction line temp after evp 49
box temp 45
Any suggestions

Thanks

overcharge
clean coil with cleaner
and check your txv why not closing
13* superheat is high

[EugeneTheJeep]

Could be an inefficient compressor? Did you try a pump down test with the SSV? Are the amps much lower then RLA? I have run into a few R-22 WI coolers, running that kind of suction pressure, I found the compressor was inefficient. But I also see you work in a much hotter ambient then I am used to.

[dmy-hvac]

if you pulled the correct micron and have correct charge in it and all checks out ok with the condenser id lean towards compressor.did you try pumping system down> your high side should not rise unless its over charged then could be a (boom!)

[Super Tech JJ]

I would guess that you are overcharged a little and you are picking up quite a bit of extra heat across the compressor.

Do you have a suction accumulator on the system? If so you can run the superheat down to about 8* at the compressor.

Your discharge temp is way high. 235* is starting to cause the oil to do so real bad things in the system. Which oil is in the system if you know? You should be able to calculate the liquid line temperature by looking at the ODT, superheat and heat of compression. With the TP chart it looks to me like your discharge pressure is about 60* high. You subcooling is high too so that supports the overcharged theory. Probably good around 12* subcooling. You may have about 20% of the condenser stacked with liquid refrigerant.

If you can dump that extra heat from the refrigerant and get the superheat where it needs to be you should be in fat city! :cool:

Good Luck,
JJ

P.S. The extra heat from the windings is what I was getting at about the high discharge temperature. On R-22 systems I don't like to see the discharge temperature above 210 Deg F. That is when the oil starts breaking down and leaving carbon if it is the older style oil.

[sarpanch2001]

Agree with Super Tech :)

[richvacr]

check txv heating bulb, adjust it to open and close

[dirtyboy103us]

your head is effecting your suction, 360 is about right for old condenser 110 + 35 degrees = 145 condensing temp r-22 =359 psi

super heat is 14 degrees should be between 6 and 8

is this box outside in these temps is so its needs some cover from sun

i would also check condenser fan blade position you might get it closer to 25 degree condensing temp if someone installed it wrong and check the shroud around it...... make sure both coils are clean also so its feeding enough gas dirty evap and txv will close down and not feed

you only need about 5 degree and it was maxed out when design for these temps so it has to be spotless and set properly to maintain during high loads

no model # or compressor # and size of box and location for a load calc.would help alot

[sarpanch2001]

your head is effecting your suction, 360 is about right for old condenser 110 + 35 degrees = 145 condensing temp r-22 =359 psi

super heat is 14 degrees should be between 6 and 8

is this box outside in these temps is so its needs some cover from sun

i would also check condenser fan blade position you might get it closer to 25 degree condensing temp if someone installed it wrong and check the shroud around it...... make sure both coils are clean also so its feeding enough gas dirty evap and txv will close down and not feed

you only need about 5 degree and it was maxed out when design for these temps so it has to be spotless and set properly to maintain during high loads

no model # or compressor # and size of box and location for a load calc.would help alot

35* condensor split High :eek:
rule off thumb no more than 30*

[ericnyc]

is there a head master?, receiver?, sight glass on this unit?

[dirtyboy103us]

35* condensor split High :eek:
rule off thumb no more than 30*


but as they age and loose their efficiency and get a little dirty that goes out the window

[Airmechanical]

Could be an inefficient compressor?

with 360 psi head pressure

that compressor sounds like it's pumping to me



.

[superheatny]

14 F superheat is high, valve does not feed enough refrigerant...check TXV, could be dead power head...

[EugeneTheJeep]

with 360 psi head pressure

that compressor sounds like it's pumping to me



.

I have seen normal to high head pressure on plenty of inefficient compressors. It is 110 ODA. Would you just overlook the amp draw based on high head pressure, and assume it was not inefficient?

But I wonder what happened to the guy that started this thread??