copeland discus oil pressure

[socotech]

Single row condenser coils. They look clean, but I'll be honest....I did not wash them.

[supertek65]

317# head sounds high!

[socotech]

Went by and checked it yesterday. Its down to 280#. Its also 98* ambient in the shade.

[Six]

317 on a unit that old 98 ambient is actually not that bad.

Does that unit have the mechanical timer ?

[supertek65]

135* SCT
130* LLT
005* SC
079*SLT
044* sst -74# SP
035* SH

HIGH EVAPORATOR TEMPERATURE
130* LIQUID ENTERING EVAPORATOR
HIGH EVAPORATOR CAPACITY
LOW CONDENSER CAPACITY
EXTREMELY LOW NET REFRIGERATION AFFECT

it is clearly low on refrigerant, i would like to see how high the head is after he gets 12 * subcooling?

317 on a unit that old 98 ambient is actually not that bad.

Does that unit have the mechanical timer ?

[Six]

135* SCT
130* LLT
005* SC
079*SLT
044* sst -74# SP
035* SH

HIGH EVAPORATOR TEMPERATURE
130* LIQUID ENTERING EVAPORATOR
HIGH EVAPORATOR CAPACITY
LOW CONDENSER CAPACITY
EXTREMELY LOW NET REFRIGERATION AFFECT

it is clearly low on refrigerant, i would like to see how high the head is after he gets 12 * subcooling?

Lol....

Liquid line is hot because units short charged and what does insuring a liquid seal in the condenser have to do with excessive head pressure. I'm not saying stack the coil with excessive refrigerant.

So it's ok to short charge a system because you're afraid your going to launch the heads off the valve plates ? Charge the thing correctly and then see what your head pressures are.

It's hackery . What does short charging do to a unit ? Lowers capacity, lowers efficiency causing the unit to run longer, can cause icing, poor cooling of the compressor windings, etc.

Ive got an old York 20 ton and a old York 30 ton split ( installed in the late 80s ) with Copelands in them and they're properly charged, running high head ( 325,330 ) and they're still in one piece after 7 years of PMs.

[socotech]

317 on a unit that old 98 ambient is actually not that bad.

Does that unit have the mechanical timer ?

Yea its got an old camstat timer

[socotech]

Lol....

Liquid line is hot because units short charged and what does insuring a liquid seal in the condenser have to do with excessive head pressure. I'm not saying stack the coil with excessive refrigerant.

So it's ok to short charge a system because you're afraid your going to launch the heads off the valve plates ? Charge the thing correctly and then see what your head pressures are.

It's hackery . What does short charging do to a unit ? Lowers capacity, lowers efficiency causing the unit to run longer, can cause icing, poor cooling of the compressor windings, etc.

Ive got an old York 20 ton and a old York 30 ton split ( installed in the late 80s ) with Copelands in them and they're properly charged, running high head ( 325,330 ) and they're still in one piece after 7 years of PMs.

I have never heard the term "short charged". What is that?

[Six]

Yep, I've got three just like it. ( two 20s and a 30 )

Old school controls with a choke coil to lower fan speed on the #1 condenser fan motor for capacity control.

One of our EX-technicians wen't out on a service call and destroyed the control wiing inside the panel on the 30 when I was on vacation.

I had to start from scratch to rebuild that panel.

[Six]

I have never heard the term "short charged". What is that?

Purposely under charging a unit to avoid high head trip or extended high head run time. ( I'm not saying you did that I just use the term to describe an undercharged unit in general )

I don't believe in it. These Yorks I have have coils that are 2 pass and in horrible shape.

They are charged to 12 to 14 degrees of subcooling and run fine and that's in Houston.

[socotech]

Ahhh yes. Short charge. I get it. Thats exactlly what I did. Afraid to blow the head of the compressor through my chest I guess. Learn something new everyday.

[Six]

Ahhh yes. Short charge. I get it. Thats exactlly what I did. Afraid to blow the head of the compressor through my chest I guess. Learn something new everyday.

I can understand the hesitancy to charge to correct subcooling when dealing with older coils and units in a hot climate but what will actually happen is your liquid line will cool down and you'll be providing your customer with 100 % of the capacity minus what it's lost because of it's general age.

You will probably be surprised to see your head drop a little.

Also you're Compressor amps will lower as you start cooling your wingdings more efficiently.

I've gotten into a few debates over this with some of our fellow techs.

You are not stacking refrigerant by providing a liquid seal and by providing a solid column of liquid to the TXVs, if your head DOES climb it's because you now have 100% capacity.


Charge it to correct super heat and let it ride. All three of my antique Yorks are charged to 12 to 15 degrees of sub-cooling and ran fine through the heat wave we had last month.