[couplux]

Is cond fans running

 

[sarpanch2001]

Tell me if this is normal?

Put a compressor in a two door reachin freezer running 404a. Ambient temp is 80 degrees. Plugged it in and thehi side quickly climbed to 350 or higher, lo side was 60 lbs and I still had to charge one more pound of 404a (4 lb to full).

Buddy told me to run it and wait it out, that it will settle down when the box cools.

9700 BTU compressor, clean cond., txv with receiver. No nitrogen inside, pulled vacuum for 90 minutes. New filter, blew nitrogen through system to be sure of no restriction.

Would trying to feed the last lb of 404a help or drive the hi side higher? Am I paranoid?

timjim something is wrong here two door RIF 9700 btu ? something wrong here according to victory there reach two door in max 1 HP which is around 4000 btu something wrong if you put M# &S#you well get anwer .also 4 LB R-404A ?in two door reach in frezer something we getting wrong info i would say it must be special aplication or wrong info

 

[lovecoldair]

I never personally clear a sightglass till the system is around normal running temp

 

[cyro]

Ditto - lovecoldair

 

[bustawrench1]

I never personally clear a sightglass till the system is around normal running temp

This may be a dumb question, but.........

Why not?

 

[lovecoldair]

Because when the box it hot your txv is going to be wide open and if you clear the sight glass to early, when the box cools down and the txv starts to close down you are going to be overcharged

 

[bustawrench1]

Thanks for the info.

I'll remember that on my next freezer job.

 

[lovecoldair]

Or a cooler .....anything with a txv and a reciever,,,,,just my openion and i have have good luck with it

Good luck

 

[Poodle Head Mikey]

Forget the plate -

Charge to proper subcooling at conditions.

Make it 3-4 degrees, throttle the suction valve to hold the compressor amps at FLA or less on pull-down. When the box is at or near temp add R until subcooling is about 6-7 degrees.

See what the head pressure is then.

I am no genius, but if I suspect an overcharge when I am working I close off the liquid line and pump the unit down and see what happens to the head pressure. If it doesn't hit 400 (that would be for R-22) I consider it to be fine to run,

 

[lovecoldair]

And if it does hit 400 psi and blows the relief ...? free gas to the customer?

Not sure i would do that but to each his own i guess

 

[Poodle Head Mikey]

What relief?

And why is the relief set for 400 lbs for R-404?

 

[jtrefrig]

have never seen a self contained 2 or 3 door freezer that held 4lbs of refrigerant . jbb

 

[timjimbob]

64 oz. yup. it what it says.

Superheat is 30 degrees. I will double check manufacture plate though.

 

[Jabarco]

Tell me if this is normal?

lo side was 60 lbs

No. Maximum suction pressure should not exceed 35 psi. You need to check the CPR (if you have one) or the TXV needs to be a MOP type.

Jabs

 

[JWB]

here's a simple rule of thumb for high side
take ambient temp and add 15
this is condensing temp
conert to pressure
ex: 100 deg day + 15 = 115 = approx 286 lbs.
you are 136 condensing - why

Any "rule of thumb" for suction? We installed a comp and are having trouble getting it to cool. 8 oz. 404 and no freezing. q-type bin mani. We do minimal refer work. 84 degrees in our shop yesterday..... coil clean, in the shade. No makkee d ice....

 

[Poodle Head Mikey]

Jwb -

thirty years ago that was add 30 for refrigeration and add 35 for air conditioning. <g>

Now it's add 15, eh? <g>

 

[rocket]

suction guideline
take design box temp and subtract TD then convert answer to pressure

TD = 10 for freezers
cooler TD will vary from 7 to 20, see heatcraft Engr Manual pagrs 21 & 23

ex: 0 deg freezer - 10 TD = -10 get pressure of -10 for your gas
same thing for coolers but get suggested TD from manual (ex:wine 15 TD, etc)

link for Heatcraft Manual
http://www.heatcraftrpd.com/resources/wiringdiagrams/H-ENGM0806.pdf

30 was standard for condenser TD for years, the new higher EER are archieved by narrowing this
which is why a 4 ton compressor is used in most 5 ton units {look at CRM 400 copeland at 130 cond (53,000 btuh) then at 110 cond (62,500 btuh 5 ton)

 

[william smith]

404a normaly runs about 300 to 325 head on a real hot day copeland recomeneds when useing blends to clear the sight glass once are use the 80 percent rule