What's wrong with this system?

[Poodle Head Mikey]

TPCo Compressor M# AJB7465AXD
Bohn Coil M# ADT0700F
Charged with R-414B
83 degree ambient
60 degree walkin box temp

245 VAC at disconnect
Both legs 124 VAC to ground
Common to Run Terms 245 VAC
Common to Start terms 272 VAC
Run to Start terms 355 VAC
Compressor draws 8.05 amps

Condenser EAT - 82
Condenser LAT - 102
Liquid pressure - 190
Suction pressure - 27
Liquid line temp - 106
Suction line temp - 75
Discharge line temp - 174
Evap EAT - 61
Evap LAT - 58

Customer calls: Box was 38 degrees all week. 7:00A this morning it was 38 degrees. 9:00A this morning is was 55.

Get there; box is 75 inside. Nothing on the condensing unit is running. Compressor is warm to the touch. Power to the disconnect. Switch off the disconnect. Pull doghouse and compressor terminal cover. Switch on disconnect. Power to ground - all three terminals. Zero volts across common and run. Pull the compressor controls cover. Unit starts. No wires are loose or burnt. Cycle unit several time with disconnect. Always starts and runs.

What was the problem?

What are the problems?

[itsiceman]

What was the problem?

Is this a trick question?
Ok I'll guess It was a dirty condenser unit over heated opened overload customer cleans the coil waiting for you in panic mode. But why was your cond. fan off (controls/wiring)?

[gas_n_go]

what does EAT and LAT stand for?

[Poodle Head Mikey]

I could not simulate the 'does not run' problem on-site. So I have no definitive idea what it was.

Nothing at the condensing unit running - sounds like the box stat stuck open. No idea why taking the controls cover off the compressor on the roof would close a stat down in the box. And a stat which had (if that was the problem) been open all day long despite the door being slammed, product moved in and out, etc.

Condenser is not dirty. Big steel fin spacing, clean, good air flow.

I do suspect that it is not the correct compressor for the condensing unit. Just my spider-sense tingling though - as I can't read the tag on the CU base plate.

I am curious if the amp draw is too high. "7465" - is that 6500 BTU's ? At medium temp that would be about 3/4 HP. 6 amps per HP at 240 volts makes it seem a bit high. But the O/L never opened while I was there and if it had been off on the O/L to start with - the condenser fan would have been running.

NO! Pressure control! The fan wouldn't run without the compressor ruuning as the head pressure would be too low to close the control.

But the compressor shell was warm - not hot to the touch.

I have been working on my kitchen, chasing the little woman around, and drinking beer on my breaks all day today - so working on this walk-in was way down on My List by the time he called. But . . . what can you do? I went.

Hell; I had to go out to Home Depot anyway. May as well fund the trip. <g>

[NedFlanders]

Entering air temp/leaving air temp

A.C. talk

[Poodle Head Mikey]

Sorry about that. It's how my start-up sheets are labeled.

[sarpanch2001]

TPCo Compressor M# AJB7465AXD
Bohn Coil M# ADT0700F
Charged with R-414B
83 degree ambient
60 degree walkin box temp

245 VAC at disconnect
Both legs 124 VAC to ground
Common to Run Terms 245 VAC
Common to Start terms 272 VAC
Run to Start terms 355 VAC
Compressor draws 8.05 amps

Condenser EAT - 82
Condenser LAT - 102
Liquid pressure - 190
Suction pressure - 27
Liquid line temp - 106
Suction line temp - 75
Discharge line temp - 174
Evap EAT - 61
Evap LAT - 58

Customer calls: Box was 38 degrees all week. 7:00A this morning it was 38 degrees. 9:00A this morning is was 55.

Get there; box is 75 inside. Nothing on the condensing unit is running. Compressor is warm to the touch. Power to the disconnect. Switch off the disconnect. Pull doghouse and compressor terminal cover. Switch on disconnect. Power to ground - all three terminals. Zero volts across common and run. Pull the compressor controls cover. Unit starts. No wires are loose or burnt. Cycle unit several time with disconnect. Always starts and runs.

What was the problem?

What are the problems?

condensing temp is 120
SC 14 deg you got juice
condensor split ltl high 38 deg
evap temp around 31 DEG
45 deg superheat what is your evap superheat if you can post you will find problem
sound like your under feed ,check txv ,due to coil td is 28 deg
if you got 60 deg box pulling down from long time high superheat high td will
go towards txv refrigeration problem not elec

[Poodle Head Mikey]

Condenser delta is 20 not 38. I still think that 20 is a bit high for a clean open condenser but it's not 38. <g>

Looks like the SSH is 45 - but the box just started and was still at 61 degrees too.

OK, but if it's a "txv / refrigeration problem not elec" then way wasn't the condensing unit running? Cycling on the compressor O/L you think ?

[sarpanch2001]

well EAT is 82 according to tecumseh pt chart 190 psig 124 deg condensing temp how come conensor split 20 deg how do you measure condensor split 124 - 82 =42 deg condensor split

[sarpanch2001]

you don,t measure LAT ? to check condensor spilt
here is some info i got may help you
Page 2 Chapter 5 Notes

Talking about efficiency, the more efficient A/C condensers have a 20, or lower, condensing split than the old standard 30. In the example of the 95 ambient with the clean condenser, the difference in the head pressure would be (95 + 30 = 125 condensing at 281#) – (95+30=115 at 245#) 36# and the difference in the liquid temperature would be (125 - 115) 10.
Condensing split is the temperature difference between the ambient temperature and the temperature at which the hot discharge gas will condense. Thirty (30) is average for standard A/C units and refrigeration units. High efficiency units are dropping that to 20 and sometimes as low as 10 by increasing the size of the condenser, more fins per inch, and condenser fan capacities to move more air across the condenser surface.

SUPERHEAT is the difference in the temperature between the vapor in the low side and the temperature at the sensing bulb. The “average” superheat is 10.
If there is no superheat (0) than the TXV is “flooding.” Note: anything below 5&#176; is low superheat.
If there is too much superheat (above 20) the TXV is “starving.”
NOTE: SUPERHEAT IS TAKEN ONLY AT DESIGN TEMPERATURE (preferable just before the thermostat cycles the unit off). Design temperature is what it is rated at. For instance, A/C is designed to provide about a 75 space temperature, medium temperature applications would be 35 to 40 box temperature, and freezers are normally 0 to –10.

[sarpanch2001]

here some more info on condensor split may help you in feature
Page 2 Chapter 5 Notes

Talking about efficiency, the more efficient A/C condensers have a 20, or lower, condensing split than the old standard 30. In the example of the 95 ambient with the clean condenser, the difference in the head pressure would be (95 + 30 = 125 condensing at 281#) – (95+30=115 at 245#) 36# and the difference in the liquid temperature would be (125 - 115) 10.
Condensing split is the temperature difference between the ambient temperature and the temperature at which the hot discharge gas will condense. Thirty (30) is average for standard A/C units and refrigeration units. High efficiency units are dropping that to 20 and sometimes as low as 10 by increasing the size of the condenser, more fins per inch, and condenser fan capacities to move more air across the condenser surface.

SUPERHEAT is the difference in the temperature between the vapor in the low side and the temperature at the sensing bulb. The “average” superheat is 10.
If there is no superheat (0) than the TXV is “flooding.” Note: anything below 5° is low superheat.
If there is too much superheat (above 20) the TXV is “starving.”
NOTE: SUPERHEAT IS TAKEN ONLY AT DESIGN TEMPERATURE (preferable just before the thermostat cycles the unit off). Design temperature is what it is rated at. For instance, A/C is designed to provide about a 75 space temperature, medium temperature applications would be 35 to 40 box temperature, and freezers are normally 0 to –10.
don,t take me wrong i am just trying to help you if think im wrong just ignor it

[Poodle Head Mikey]

Entering condenser - 82

Leaving condenser -102

difference - 20

[sarpanch2001]

come on dude info i just post that is from book