charging my system and I have some questions

[Impulse]

I have an r22 heat pump package unit with design pressures of 150 on the low and 300 on the head. it's about 55 degrees outside, I have the inside temp set to 71. The low pressure is ranging from 50 to 60 psi (about 20 degrees) and head is ranging from 300 psi (115 degrees) to 350 psi (130 degrees). I was wondering what might be wrong. I don't have a sh or sc detector, but any help would be useful. It is heating the house, though the cycle seems rather short which, i would speculate, will drastically increase my electric bill

[hvacman14]

back away from the heat pump, if it is heating your house do not mess with it, if it is not heating your house, please call someone who has the knowledge to interpret the numbers you have given, this is something that unless you are qualified open up and work on you should not, as you could injure yourself and/or burn your house down

[Impulse]

ok i'll re-state my previous post. I am an apprentice hvac technician of 2 years, and I would like help on diagnosing the problem of this system. It wasn't heating the house earlier, and I charged the system with MY guages, and MY r22 freon that I bought because I have have my cfc certs. I just have not had much interaction with heat pumps, and am finding this confusing as to why there is no steady pressure, and why the suction pressure is so low compared to the design specs. also, can it even be diagnosed properly without sc or sh being calculated

[beshvac]

I have an r22 heat pump package unit with design pressures of 150 on the low and 300 on the head. it's about 55 degrees outside, I have the inside temp set to 71. The low pressure is ranging from 50 to 60 psi (about 20 degrees) and head is ranging from 300 psi (115 degrees) to 350 psi (130 degrees). I was wondering what might be wrong. I don't have a sh or sc detector, but any help would be useful. It is heating the house, though the cycle seems rather short which, i would speculate, will drastically increase my electric bill


What's a "sh or sc detector"? :putergreet: Ya know it's not a good idea to charge when it's 55 degrees?.....

[hvacman14]

the design pressures and the operating pressures are two totally different things, there should be a charging chart on the machine, do not charge to the design pressures thats all im gonna say, and have probably already broken the no DIY rule!

[Impulse]

What's a "sh or sc detector"? :putergreet: Ya know it's not a good idea to charge when it's 55 degrees?.....

I don't have any device to measure sub cooling or super heat, just my manual guages. and I know it's not the best idea to charge when it's 55 degrees, but when a unit is running all night and can barely achieve 65 degrees, there was obviously a problem. I would have thought that the low pressure would be a little higher after I was done, but I guess that's the normal operating pressure of this unit. there is no charging chart on the machine, nor is there an installation or owner's manual to be found.

[Impulse]

and i'm not really asking for diy advice. I didn't ask or recieve info on how to charge a system, nor did I ask or recieve info on how to perform a diagnoses or how to go about solving the problem. my now main concern is, is it normal for the pressures to be fluctuating during the operation of a package unit heat pump? (which I am coming to the conclusion the answer is yes), and is it normal that the low operating pressure is only 20 degrees (50-60 psi) with the outdoor temp of 55 and indoor set temp to 70?

[classical]

and i'm not really asking for diy advice. I didn't ask or recieve info on how to charge a system, nor did I ask or recieve info on how to perform a diagnoses or how to go about solving the problem. my now main concern is, is it normal for the pressures to be fluctuating during the operation of a package unit heat pump? (which I am coming to the conclusion the answer is yes), and is it normal that the low operating pressure is only 20 degrees (50-60 psi) with the outdoor temp of 55 and indoor set temp to 70?

Son you need to read the site rules, if you cannot perform and understand this simple task good luck.

Next if you are in the HVAC profession, get your post count up to fifteen and apply for pro status. Once you become a PRO we can give you all the help and knowledge you can handle in the PRO forums.

In the meantime have a PRO come look at the system, if you work for a company ask a seasoned tech come out and ask to assist so you can learn.

[pauls heating &]

ok i'll re-state my previous post. I am an apprentice hvac technician of 2 years, and I would like help on diagnosing the problem of this system. It wasn't heating the house earlier, and I charged the system with MY guages, and MY r22 freon that I bought because I have have my cfc certs. I just have not had much interaction with heat pumps, and am finding this confusing as to why there is no steady pressure, and why the suction pressure is so low compared to the design specs. also, can it even be diagnosed properly without sc or sh being calculated

step away from the refrigerant grasshopper...call a sr tech in your company
for a lil help..or get your post count up where we can help you in the pro side

[motoguy128]

I don't see how a short cycle is a problem here. That means it's putting out plenty of heat. If it's only 55F, which depending on where you live, the unit shuld be running about 1/3 of the time. If anything it might indicate the unit is oversized.

Do you have a thermometer? Can you measure static pressure? If yes and yes, then you can calculate the totl BTU's based on temperature rise and airflow. Take CFM x Temp rise x 1.08. Does the numer seem about right for that model given hte outside tmepratures? Use the equipment data sheets to determine what the capacity should be at given conditions.

[beenthere]

Moved to Tech to Tech Forum.

[dan wong]

I recommend you have your mentor standing beside you, walk you through step by step, have him explain what's happening as you go through the steps. You will learn a lot.

[Impulse]

thanks everyone for the posts, and for all who commented on me getting up enough posts to get to PRO status, well, that is one of my goals in this line of questioning. I also got the one answer I was looking for earlier that NO, I can not accurately determine the cause of the low pressure without determining the sub cooling and super heat first, which takes me out of the game of any further diagnosis of my system until I aquire a thermometer to attach to the suction and liquid lines. A sr tech at my company has one so I will be using his aid in the near future. Thanks again people! oh and motoguy, I am positive that this 3 ton package unit definitely oversized for the house, but I will be doing air distribution calculations soon.

[classical]

thanks everyone for the posts, and for all who commented on me getting up enough posts to get to PRO status, well, that is one of my goals in this line of questioning. I also got the one answer I was looking for earlier that NO, I can not accurately determine the cause of the low pressure without determining the sub cooling and super heat first, which takes me out of the game of any further diagnosis of my system until I aquire a thermometer to attach to the suction and liquid lines. A sr tech at my company has one so I will be using his aid in the near future. Thanks again people! oh and motoguy, I am positive that this 3 ton package unit definitely oversized for the house, but I will be doing air distribution calculations soon.

Well welcome and see you on the dark side soon.

[walklong]

Impulse, if you search on "heat pump charging in heat mode" you'll find that it's a LOT dicer to accomplish - I'd echo the multiple recommendations above to either wait for a warm enough day that can both allow operation in cooling and that the charts will allow a close approach to your target superheat. If you've got an android phone or tablet, HVAC buddy can help with the calculations. (Although I, too, lust for the equipment that will simply tell me what number to aim for - understanding the underlying science and engineering will carry you far).

[Purcell1]

your a second term and dont have a thermometer? how do you do any sort of diagnosis? calc sub cooling and superheat should be the first thing you were taught.