DD68 pressure

[Uncledaddie]

Sorry if this is the wrong place for this I am still trying to figure this out. I recently bought a beverage air I think it is a DD68. The tag is missing
Does anyone know the pressures for 134a on high and low side and the freon weight that should be added
I got this unit to fix it up I took it apart cleaned it out it back together ( the cabinet not mechanical ) after it was not cooling right so I charged it up interior temp running at 40 degrees high side is around 220 low at 20 most of interior coil is sweating but has only been running about 2 hours kinda rattled on there
Any idea of pressures anyone

[THE ICEMAN]

Sorry if this is the wrong place for this I am still trying to figure this out. I recently bought a beverage air I think it is a DD68. The tag is missing
Does anyone know the pressures for 134a on high and low side and the freon weight that should be added
I got this unit to fix it up I took it apart cleaned it out it back together ( the cabinet not mechanical ) after it was not cooling right so I charged it up interior temp running at 40 degrees high side is around 220 low at 20 most of interior coil is sweating but has only been running about 2 hours kinda rattled on there
Any idea of pressures anyone

First of all, welcome to the forum...
Temperature & pressure are directly related. Pressures are not static, they will vary according to conditions. As the temp in the box lowers so will the low side pressure & correspondingly the head pressure will drop. In ideal conditions, your starting pressures with a warm box should be somewhere in the neighborhood of 28psi low side & 175 high side. As the unit cools the pressures should drop as well. The low side should be about 14psi at shut off. Keep in mind your ambient conditions may vary.
You say you charged it up... Did you pull a vacuum on the system first? Your head pressure is too high, it should be no more than 175psi, and your low side is too low for the box temp. Those units are what's termed "critical charge" meaning they need a specific amount of refrigerant. You can't simply "charge it up". That unit could take anywhere in the neighborhood from 8 oz. to 12 oz. One ounce either way can cause problems.
Given the information you provided I would suspect you have problems other than refrigerant charge.

THE ICEMAN

[Uncledaddie]

Thanks iceman
Woke up today went out and checked inside cabinate was about 32degrees outside temp at about 85
I turned it off hooked up my gauges and everything went wacko when I turned it back on. Not cooling suction was at -20 high at110.
I thought I may have had a leak put in a little dye but can't find anything (put dye in yesterday)
Guy I got it from said he replaced the compressor
I think I am just going to start over and trace everything out vacuum it down and just start again
It has just been a while since I have worked on these things
Right now after adding a little freon I am at suction 3 high at175 outside at 88 internal cabinate at58
Suction line inside cab at evap 63 outside at compressor 97 highside outside at the compressor 108 after cond 97
This does not sound right to me let me know what you think if I should just start over

[THE ICEMAN]

Sounds like you have something restricting flow in your system. Put your low side gauge on the system & let it run for a few minutes. Keep your hand on the drier at the same time, it should feel warm. If it pulls down into a vacuum again cut the power & watch your gauge. The needle should rise to static pressure fairly quickly, within a minute or two. If the needle just hangs in a vacuum or rises VERY slowly, you have a restriction in either the drier or cap tube.


THE ICEMAN

[Uncledaddie]

Ok before I saw this I vacuumed it down and recharged to 8 oz so far so good after about an hour of running its at about 50 degrees inside outside air about 90 air coming out of evap about 45 temp going in cond about 108 coming out at about 95 pressure at about 8 and 170
Not sure if it is cycling though have to turn thermostats almost all the way off to get to to shut off
But it is not to temp yet

[Uncledaddie]

I also just took off evap cover the bottom of the coil is icing up temp at 25 at inlet and 45 at outlet is it because it is running too long
Think I need a thermostat

[Uncledaddie]

Ok iceman I did what you said but it wasn't in a vacuum low side comes up ok at first then slows down takes about 2 minute to equilze
You said drier or cap tube
Is the cap tube that very tiny line coming out of the drier used to meter the freon
Also if it is restricted wouldn't that cause the inlet on the evaporator to freeze up
That's what it is doing about one inch up from the bottom
After it turns off only takes less than a minute to defrost
I did check for air leaks I closed those off to make sure that wasn't keeping from running too long
Do you think I should replace the drier and thermostat

And thanks for your help trying to get this thing going for my daughters wedding in a couple of months

[THE ICEMAN]

I can only go by what you are telling me. In one post you say the unit pulls into a vacuum & now you say it isn't soooo...
The t-stat is not your problem IMO. When you have the evaporator cover off & there is no airflow over the coil, the coils should get very cold very fast & the t-stat would sense that there is no heat load & shut the unit down. You're telling me you only see a little bit of the evap frosting up when it should be even across the coil with no airflow / heat load. This tells me either the unit is way undercharged or there is a restriction.
Turn the unit on, keep the door closed & watch it for a good half hour. When the unit is running with everything in place, what does the drier feel like & what does the suction line near the compressor, about three or four inches away, feel like? The drier should be warm & the suction line cold, preferably sweating. If the suction line is frosted, it is overcharged.
Given what info you have provided it's possible you have a low charge situation but I'm still leaning towards a restriction in the system.


THE ICEMAN

[Uncledaddie]

Ok I am having trouble posting back so short version this time
Flushed system recharged
Changed thermostat now it cycles on and off between 33 and 40 degrees
It is warm at the drier but only room temp at about 6 inches before the compressor the whole Evap is sweating now and about 6 inches from it but after that no I can remove the evap cover and take a peek and still continue air flow
It still lightly freezes up but just on the bottom then defrosts when off excep for a little of the ice I will try to attach a photo
Do you still think it is restricted
The drier?
Or cap tube

[Uncledaddie]

This is a photo