Heat craft walk-in cooler got me stumped

[royd2]

did you ever check the super heat? or amp draw? does it have a head master or is it fan cycle delay?

[royd2]

or both

[Tommy knocker]

Sometimes it will flood the liquid line. Meaning that the condensor coil would act over sized. This happens when the restrictor piston gets stuck from bad seal or when it is over extended from "dead heading" this is caused from charging in the discharge line when breaking a vacuum.

Interesting. Not what I was looking for. I suspect undercharge. Not enough liquid for system when ambient drops, at night, so little to no motor cooling. Comp trips on thermal, box temp continues to rise, thermal resets, comp over heats, trips on thermal, box temp continues to rise and so on. Any ambient above 75-80 the headmaster souls not be by passing. Unless system is undercharged or headmaster is malfunctioning like you pointed out.

[pyramidhvacr]

If headmaster is bypassing hot gas in the liquid line both and compressor be very hot. Under charge system get the head psi up. What freon??? R404 need 265psi . 175psi headmaster is open pumping hot gas it to the liquid line this will pump all the oil out of compressor due to very high supper heat. Sight glass is hot too and may only see oil flowing not freon. Easy test pump down on high valve watch sight glass empty's then reopen see it top off. Dead heading is a tee pipe. I charge system 25 yrs in liquid line after vacuum. This is not dead heading how ever told you this is a (D>A>)

[Tommy knocker]

If headmaster is bypassing hot gas in the liquid line both and compressor be very hot. Under charge system get the head psi up. What freon??? R404 need 265psi . 175psi headmaster is open pumping hot gas it to the liquid line this will pump all the oil out of compressor due to very high supper heat. Sight glass is hot too and may only see oil flowing not freon. Easy test pump down on high valve watch sight glass empty's then reopen see it top off. Dead heading is a tee pipe. I charge system 25 yrs in liquid line after vacuum. This is not dead heading how ever told you this is a (D>A&gt

R22

[pyramidhvacr]

R22

If coil is 9000 btu use a 3/4 hp txv if 1 hp ok but has to close down more. Never open more than 1/4 turn from closed to start. Charge system At 35/175 under charged or txv flooding. No high Psi 80 deg head (225) Did u clean cond. first??? (WATER) not co2. Is evap. coil clean??? / Never charge a system by low side meaning 35/40/45/ first get heap psi up If compressor can not pump heat in to the coil it never start to frost after txv. The 3/8 line on the txv need to be warm not hot due to the headmaster pumping hot gas in to the coil. Must start TXV close 1/8 -1/4 turn open . Never ck supper htg at coil only at compressor. Never colder then 25/30 degs. Now some scroll must run colder. Check Coil BTU next ck compressor if side at same btu at 25 deg coil.

[Tommy knocker]

If coil is 9000 btu use a 3/4 hp txv if 1 hp ok but has to close down more. Never open more than 1/4 turn from closed to start. Charge system At 35/175 under charged or txv flooding. No high Psi 80 deg head (225) Did u clean cond. first??? (WATER) not co2. Is evap. coil clean??? / Never charge a system by low side meaning 35/40/45/ first get heap psi up If compressor can not pump heat in to the coil it never start to frost after txv. The 3/8 line on the txv need to be warm not hot due to the headmaster pumping hot gas in to the coil. Must start TXV close 1/8 -1/4 turn open . Never ck supper htg at coil only at compressor. Never colder then 25/30 degs. Now some scroll must run colder. Check Coil BTU next ck compressor if side at same btu at 25 deg coil.

????????

[2sac]

????????

Not enough question marks

[54885488]

On a unit like this what would you want to see for superheat anyway ?

[markettech]

On a unit like this what would you want to see for superheat anyway ?

Generally speaking, you're looking for 4F to 6F SH at the evap on low temp and 6F to 8F SH at the evap on medium temp. That said, one must always be cognizant of the SH reading at the pump.

[54885488]

How much higher are normal readings at the pump for medium and low temp systems ?

[markettech]

How much higher are normal readings at the pump for medium and low temp systems ?

SH at the pump is not application driven (it doesn't matter whether medium or low temp).

To prevent the possibility of liquid floodback to the compressor, you never want to see the SH below 20°F.

Likewise, to prevent a pump from seeing an early grave by forcing it to operate outside of its design envelope, you never want to see the SH above 40°F.

So there's your range......between 20°F and 40°F at the pump.

[54885488]

SH at the pump is not application driven (it doesn't matter whether medium or low temp).

To prevent the possibility of liquid floodback to the compressor, you never want to see the SH below 20°F.

Likewise, to prevent a pump from seeing an early grave by forcing it to operate outside of its design envelope, you never want to see the SH above 40°F.

So there's your range......between 20°F and 40°F at the pump.

Thank you markettech that clears up so much .