weigh it in, and don't forget to calculate line set length and filter drier into the total charge. I also like to mark the units total charge added, inside the service panel when done.
I have installed a GSX13 - 2 ton R410
The unit was commissioned by licensed HVAC technician.
The unit came precharged for 15ft - 5/8 tubing.
According to tech at Alpine, additional charge is to be:
23 1/2 ft actual length - 8 1/2 X .6 = 5.1 oz
90 deg elbow (formed into supplied tubing) - 2 1/2 X .6 = 1.5 oz
For a total of 6.6 0z which was what tech added.
I have just noticed that the unit comes WITH filter/drier (I gave tech the specs that came with unit) but he installed another one.
My questions are:
How will this affect charge?
He said unit would run better with TXV and hard start cap. Is that true and why didn't Alpine recommend?
How valid is temperature rise of 110 deg F. on discharge tube to verify correct charge?
BTW, I found it VERY difficult to get a HVAC tech to commission unit. Most companies wanted to sell and install complete units. I was a journeyman SM in my previous life so installation of units was no problem. Unfortunately, I've not contacts in this area (retired).
I believe each unit has its own charging method and techs should read this information prior to doing any charging. On my ICP unit it states during heating mode to weigh it @ .6 ounces per ft of Liquid line in excess of 15 ft with a factory charge of 14.6 pounds... so you are faced with more work if you do not know what is in there already... would have to evacuate it all out and start over... could take a while charging if its real cold outside.
Weigh in is only reliable method to charge a HP in heating mode
There has not been any accurate method to charge in heating season other than weighing it in. In heating there are too many unfixed variables to go by any other means. Years ago some companies used the discharge line temperature as a guide but I found his is no more reliable than many other methods that don't work.
When you adjust the charge for the lineset, use ACTUAL length of the liquid line and not equivalent length.
Charging HP in Winter to hottest point by supper heat
Check the supper heat probe compressor side or txv, I place 2nd probe on hot gas highest heat @ 35 deg supper heat. Over 35 deg temp starts to fall and @ 20deg min supper heat mfg compressor states hot gas to low to heat the home. So under about 35 deg supper htg the compressor is flooding. Note removing the fitting (hoses) you see white your flooding the system. Hot Gas has no liquid in it at all. Dirty outdoor cond unit. dirty filter no air flow, lack of return air ductwork for about 95% of system is like a dirty out door cond. unit . Lack of air flow can be check by removing a panel on air-handler. Heat pumps need 400 sq. ft. per ton. For best heating a home.
ck this site on r22 ver 410a http://fire.nist.gov/bfrlpubs/build02/PDF/b02186.pdf
read the CONCLUSIONS
outdoor temperature increased, the R410A system performance degraded more than the R22
Weigh it in ??? no testing supper htg Quess you got to much time on your hands. TIME IS MONEY. AT $85 hr and $55.00 lbs R22 . Weight by chart is a quessing game. Testing both SH and temp on hot gas line you can see the temp going in the evap or many i say condenser in the home in hp mode. My self I dont like 2 trip making a free call in the summer to ck it again is DUM. My main work is Refrigeration (TXV'S) all the time resetting them. These preset txv or a joke. But the only way in htg pump mode set supper heat remove or add freon. COPELAND COMPRESSORS min. SH IS 20 DEG TO 45.
SETTING A TXV TO 10-12 DEG ???? DUM DUM DUM . THIS IS SETTING ON THE GIVE A WAY CHART. NOT TRUE MFG SETTING. (10-12 DEG IS WHAT WALK-IN EVAP. COIL SET AT. I NEVER SET ANY THING THIS WAY. Set Supper Heat At Compressor you never flood the compressor Remember A Compressor makes HEAT and flooding it is removing HEAT.
The warmer the compressor not sweating in the summer the better cooling in the home.
CHARGE BY SUPPER HTG NOT BY MFG CHART/ OR WEIGHT . THIS IS ONLY BALL PARKING IT NOT A TRUE CHARGE. YES SUPPER HTG AND SUB COOLING CAN BY AT SAME TIME.
BUT NOT IN HEAT PUMP MODE.
What happened to going by the charging chart? The tech. should be able to judge the length of the line set and add what he feels right. Then go by the chart on the panel. On new construction when its 40 degrees in the residence it is a b-tch. Your tech should also have a feel for it