Charging question with headmaster?

[KB Cool]

Hey guys,
It's been a while since I posted in this section of the forum. Been working on mostly Heat pumps and some gas. But anyway we are installing 3 new walk-ins all with headmasters. My question is Do I charge to 90% receiver first, Clear sight glass, check superheat at evap then weigh in additional charge for headmaster using the sporlan chart. Or should I just weigh in the entire amount including additional for headmaster, then check SH. Almost forgot, "Outdoor ambient temp should be in the 70's".
Thanks

[engineerdave]

Clear your SG, set your SH, then Top Off your charge.

[markettech]

http://www.heatcraftrpd.com/resources/techtopics/Tech%20Topics%20615463.pdf

[KB Cool]

http://www.heatcraftrpd.com/resources/techtopics/Tech%20Topics%20615463.pdf



Okay now I am confused. Should I never go over 90% receiver capacity even if it has a headmaster.

[smilies]

I wouldn't. What about pumdowns?

[KB Cool]

I think I'll just weigh in 90% of receiver capacity.
Sound good.

[k-fridge]

I think I'll just weigh in 90% of receiver capacity.
Sound good.
All receiver capacity is for is to determine a maximum charge. In most systems you'll just be waisting refrigerant if you put that much in. Clear the glass, check SH, add per Heatcraft manual.

[idontgetit]

You should never go above 80% of the reciever capacity!

Temp changes and liquid expansion will cause hydrastatic pressure to rupture the reciever or blow the fuseable link if equipped.

[KB Cool]

Okay I'll clear the glass while weighing the charge. Then after glass clears,I'll add an additional 15%.
Will that satisfy the start-up checklist for warranty purposes?:D

[thornguy]

The purpose of the HP valve is to flood the condenser in low ambients so that hot discharge gas, along with a mixture of liquid from the condenser can maintain head pressure for good pressure drop across the TXV.
The receiver is generally sized to hold 125% of the flooded condenser capacity. If a line run is less than 20', simply weigh in the 90% receiver capacity. When the condenser is completely flooded, you will still have a 25% level in the receiver to cover the dip tube and maintain good liquid in the liquid line.
If the line run is longer than 20', the pumpdown solenoid needs to be as close to the txv as possible and an additional charge will need to be added based on page 30 of our I an O.
http://www.heatcraftrpd.com/resources/install/H-IM-64L.pdf

[thornguy]

One more note:
Only after the compltete charge has been added should the superheat be looked at. The box should be down to within 10° of desired box temp before trying to acheive your typical 20° compressor superheat. Scroll compressors can be adjusted down to 15° superheat.

[markettech]

If the line run is longer than 20', the pumpdown solenoid needs to be as close to the txv as possible and an additional charge will need to be added based on page 30 of our I an O.


Thornguy..........................Heatcraft guy?

[thornguy]

Yep.
First slow day I've had in a very long time and found this website and thought I'd throw in my 2 cents worth.

[markettech]

Welcome to the best forum on this site!:D

I look forward to learning a thing or two;)

[thornguy]

I might do some learning from you guys.
If time permits, I will try and poke in from time to time.

[KB Cool]

The purpose of the HP valve is to flood the condenser in low ambients so that hot discharge gas, along with a mixture of liquid from the condenser can maintain head pressure for good pressure drop across the TXV.
The receiver is generally sized to hold 125% of the flooded condenser capacity. If a line run is less than 20', simply weigh in the 90% receiver capacity. When the condenser is completely flooded, you will still have a 25% level in the receiver to cover the dip tube and maintain good liquid in the liquid line.
If the line run is longer than 20', the pumpdown solenoid needs to be as close to the txv as possible and an additional charge will need to be added based on page 30 of our I an O.
http://www.heatcraftrpd.com/resources/install/H-IM-64L.pdf


Thanks for the info.
I ended up weighing in what was stated on condensor data plate. I did not see the info on the data plate the first time I looked at it, I guess I wasn't expecting it to be their either. These 3 units (ICS) are pre-charged (line-sets included)from factory but this particular one developed a leak in shipping.So I had to repair. Just waiting for electricians to finish up so we can fire them all up and see how they are doing.

[akpunkacr]

what i usually do is top off the glass and add an additional 1/2-1 lb determining the size of the system but it's not uncommon to run an outdoor cond unit with an ambient below 10 degrees for weeks on in...ex. i live in juneau ALASKA

[Airmechanical]

http://www.heatcraftrpd.com/resources/techtopics/Tech%20Topics%20615463.pdf

its all right there is'nt it!



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