Checking charge on HP in heating

[stickinit2thman]

Wouldnt a heat pump operating in heat mode be the same as checking charge on refrigeration system cooling? ie: would the superheat and subcool be similar to refer syst? thats hooking hoses&therms to true suct. line and liquid line. i havnt done alot of refer work and was wondering if my theory is correct?

[stickinit2thman]

Im trying to use my SMAN3 for heatpumps, any help here?

[dan wong]

Wouldnt a heat pump operating in heat mode be the same as checking charge on refrigeration system cooling? ie: would the superheat and subcool be similar to refer syst? thats hooking hoses&therms to true suct. line and liquid line. i havnt done alot of refer work and was wondering if my theory is correct?

On heat mode; be sure to remove your blue hose from suction line and connect it to the third port The third port is usually located on the metal panel it will have a capillary tube going to the accumulator- bypassing the reversing valve. If you don't do that, you will lose your low side gage (mechanical type), not sure about the Digital type.

[garyed]

Unless you have the manufacturers data for charging in heat mode its just an educated guess. A lot of HP's have pistons at the outdoor unit & I don't know of any that give you a SH chart for heating mode. Even a lot of txv outdoor units don't give you a SC number for heating either. Some give you a chart & some don't. There are some ballpark ways to do it but its usually a guess without weighing in the complete charge. Ball parking works fine though once you get the feel of it.

[stickinit2thman]

Unless you have the manufacturers data for charging in heat mode its just an educated guess. A lot of HP's have pistons at the outdoor unit & I don't know of any that give you a SH chart for heating mode. Even a lot of txv outdoor units don't give you a SC number for heating either. Some give you a chart & some don't. There are some ballpark ways to do it but its usually a guess without weighing in the complete charge. Ball parking works fine though once you get the feel of it.

yes i learned all that stuff 15 years ago, thats kinda my point,if we are so accurate in cooling why not heating, i think we would see alot less over/under charging, just after 21 years of hearing weigh in or charge in cooling, what if thats not possible,No info on charge weight etc. just have always checked my heating charge by delta t (outdoor and indoor) to verify proper heating. Dont anyone else? P.S. i just dont feel its accurate enough,simulating 95deg, why dont we just publish heating sh$sc? would make troublshooting alot easier during heating.

[flanders]

yes i learned all that stuff 15 years ago, thats kinda my point,if we are so accurate in cooling why not heating, i think we would see alot less over/under charging, just after 21 years of hearing weigh in or charge in cooling, what if thats not possible,No info on charge weight etc. just have always checked my heating charge by delta t (outdoor and indoor) to verify proper heating. Dont anyone else? P.S. i just dont feel its accurate enough,simulating 95deg, why dont we just publish heating sh$sc? would make troublshooting alot easier during heating.


Good points! Makes sense. :cheers:

[stickinit2thman]

Good points! Makes sense. :cheers:

thanks flanders, i intend on trying to build a data base of sorts during this winter and use this for determining consistant results. ill keep everyone informed if i come up with a break though or even useable consistant results, i feel sure im on the right track.We still need sh&sc anytime the comressor is running, right?What happens when the outdoor TXV fails or gives a problem, how ya gonna know?guess?:.02::putergreet: stickinit2thman

[SBKold]

Search for Discharge superheat discussions. Im sure u have applied for Pro. Much more detailed info on that subject.

[stickinit2thman]

Search for Discharge superheat discussions. Im sure u have applied for Pro. Much more detailed info on that subject.
ok im working on pro status, thanks for your help.

[Tommy1010]

Found this online. Its pretty blah blah in the beginning, but towards the bottom it gets more detailed of what is THEIR way of charging in winter months.

http://hvacreducationtechtips.blogspot.com/2010/03/how-to-charge-air-source-heat-pump-in.html

[stickinit2thman]

Found this online. Its pretty blah blah in the beginning, but towards the bottom it gets more detailed of what is THEIR way of charging in winter months.

http://hvacreducationtechtips.blogspot.com/2010/03/how-to-charge-air-source-heat-pump-in.htmlThanks for the reply,thats what im looking for,I knew there had to be a better way,As you can problably tell ive never been to school formally on HVAC, was pretty much handed keys to truck and a nifty peice of cutting edge technolgy(at the time)a nextell! and thown to the dogs, Over the years ive doggedly pursued info and have read HVAC technologies textbook and attended numerous feild seminars,after 21 years I find still find i have gaps in my knowlage base but seldom find a problem that stumps me,somethings i figured out something completly on my own only to find it as accepted practice later on, but have also had the opposite results also lol. Thanks again for your help,any day i dont learn something new i feel it was a wasted day,cant wait untill i get pro status, as im sure to learn tons stickinit2thman:cheers:

[Maximum19]

IF THERE IS NO CHARGING CHART THEN THE MANUFACTURE CAN TELL YOU WHAT THE LINE TEMP/SUB COOLING SHOULD BE FOR THE SYSTEM. THEY TIPICALLY HAVE A BASIC RULE FOR THERE OWN SYSTEMS.

[daniel87829]

like said earlier call manufacturer or the supply company that deals with the unit

[garyed]

There are still a lot of units that do not have a defined way of charging a HP inufacturers charging specs then you stil have to wing it. Thats probably half the HP systems I work on in the winter & where I am HP's are about 90% of the market. I know i the heating cycle. If the info is not on the equipment & you don't have any mant sounds hackish but I do it mainly by pressures since most do not have txv's at the outside unit. You guys might laugh but its been working for me for a lot of years. I add 40 to 45 degrees to the outside temp & try to get the head what it would be in cooling. So at 45* to 50* outside the head pressure should look like it does in cooling on an 85 to 90* day. I tell the customer to call me back in the warmer weather if it doesn't seem to be working right. I rarely get a call back but if I do its usually a little undercharged & its usually because of a leak.

[tstcstu]

Lennox is putting the info on the new units for charging by subcooling in the heat mode you need to know the correct INDOOR MODEL #

[Milk man]

Lennox is putting the info on the new units for charging by subcooling in the heat mode you need to know the correct INDOOR MODEL #

Lennox leading the way again.

[pacnw]

IF THERE IS NO CHARGING CHART THEN THE MANUFACTURE CAN TELL YOU WHAT THE LINE TEMP/SUB COOLING SHOULD BE FOR THE SYSTEM. THEY TIPICALLY HAVE A BASIC RULE FOR THERE OWN SYSTEMS.

first, loose the capitals, it is like you are yelling.

second, as stated already, most mfr do NOT have info for charging in heat mode. They say to get it close and return in the summer to dial it in.

[coolinman]

Remember STICKINIT !!!!!!!! What we do as professionals is to move heat – don’t matter if we move heat into the structure or out of the structure. To remove heat in our industry we circulate a refrigerant thru a sealed system and create a condition where heat flows naturally under the laws of physics. With heat pumps the ( DELTA “T”) between the ambient and refrigerant changes between the cooling and heating mode. You as a service personal should know this or you will probably cost your employer extensive repair cost as well as warranty cost. Your question confirms the need for a qualified technician.

[stickinit2thman]

Remember STICKINIT !!!!!!!! What we do as professionals is to move heat – don’t matter if we move heat into the structure or out of the structure. To remove heat in our industry we circulate a refrigerant thru a sealed system and create a condition where heat flows naturally under the laws of physics. With heat pumps the ( DELTA “T”) between the ambient and refrigerant changes between the cooling and heating mode. You as a service personal should know this or you will probably cost your employer extensive repair cost as well as warranty cost. Your question confirms the need for a qualified technician.Thats pretty much what i was saying, wasnt asking for instructions, sorry bout the misscommunication, I do uderstand exactly what you said and have been sucsesfully and accurately charging them by using delta-t and heat flow physics, its how i taught myself to do it after gathering data, but have never seen it published or even discussed officially. Again I realize I should have phrased it differantly.I have charged heatpumps like the book (Heating&A/C Technologies)said by simulating a 90deg. day by blocking condenser fan airflow and charging in cooling, also have ,learned by checking readings on properly charged units(weighed in charge) and using the delta-t method (my usual method now)Was just wanting other opinions and published data& why manufacturers dont publish. Thanks for you reply:cheers:

[stickinit2thman]

Thats pretty much what i was saying, wasnt asking for instructions, sorry bout the misscommunication, I do uderstand exactly what you said and have been sucsesfully and accurately charging them by using delta-t and heat flow physics, its how i taught myself to do it after gathering data, but have never seen it published or even discussed officially. Again I realize I should have phrased it differantly.I have charged heatpumps like the book (Heating&A/C Technologies)said by simulating a 90deg. day by blocking condenser fan airflow and charging in cooling, also have ,learned by checking readings on properly charged units(weighed in charge) and using the delta-t method (my usual method now)Was just wanting other opinions and published data& why manufacturers dont publish. Thanks for you reply:cheers: That was kinda embarrassing considering im usually the one preaching to all about moving heat and the importance of proper airflow and charge. Just trying to increase my knowlage of subject.Not trying to convince you that im a hack, i realize it kinda souned that way but not that much.:.02:

[marvin]

a year or so robo posted a method accepted by goodman by
measuring the discharge temp. maybe he will chime in
& re post it. i used it on a couple of units of other brands &
it worked out good.

[coolinman]

Remember to always check your superheat and subcooling. You need to be sure you don't have liquid refrigerant coming back to the compressor so make sure you have superheat in the return gas line to the compressor. The charging information for the unit should provide this value. Also subcooling if using Expansion valves will tell you if your liquid line is completly full of liquid. You should also study up on how to check for indoor airflow. This is extreamly important and often never checked. Look up checking Duct Static Pressure to verify air flow. Also checking velocity. Remember CFM = FPM times Opening size (in Sq. Feet ) Keep studing.

Best regards

[garyed]

a year or so robo posted a method accepted by goodman by
measuring the discharge temp. maybe he will chime in
& re post it. i used it on a couple of units of other brands &
it worked out good.

It was 126* + the outside ambient should be the temp of the hot gas line between the compressor & RV. Goodman used to print that on their charging instructions in heat mode before they went to 13 SEER.

[stickinit2thman]

Remember to always check your superheat and subcooling. You need to be sure you don't have liquid refrigerant coming back to the compressor so make sure you have superheat in the return gas line to the compressor. The charging information for the unit should provide this value. Also subcooling if using Expansion valves will tell you if your liquid line is completly full of liquid. You should also study up on how to check for indoor airflow. This is extreamly important and often never checked. Look up checking Duct Static Pressure to verify air flow. Also checking velocity. Remember CFM = FPM times Opening size (in Sq. Feet ) Keep studing.

Best regardsI am dont worry,as you can problably tell im not satisfied with not understanding or missing peices so to speak. I agree with airflow, used to only check superheat and delta-t to verify airflow, but in the last year i have purchased an digital manometer and have since gotten an education in determining proper airflow and proper installations. Have found very few since that are in spec. and fewer still that are even close.I swear to god 99% of installing contractors in this area are extreamly incompetent concerning air distribution/duct systems.Now to be fair im commenting on the ones ive personally been called to, and im aware as everyone should be that its a realatively small sampling compared to area and population, but also it doesnt seem to matter the size or popularity of the contractors, as ive been suprised a few times that the company I'm going behind would do such shoddy work or improperly sized duct/units. Its a living correcting them though so im not complaining only commenting.And thanks to everyone who commented youve been a big help.Hope to see ya on the other side soon(Pro):.02:

[stickinit2thman]

The main conclusion ive come to is you can keep it kinda simple and get pretty accurate,if you understand heat flow and the refrigeration system and how to use a P/T chart you should be able to evaluate and charge any system in any mode in just about any ambient. Just use coomon sense and proper refrigeration methods and you will be fine.:.02: