First I’d like to state that this is not a DIY question. If a procedure is forthcoming in this thread, I’ll have it performed by a professional.
Specifically I would like to know if there is a procedure to determine if high head pressure is being cause by non-condensables in the system, baring evacuating the system and recharging. The reason why I like to know about this will become apparent in the rest of this post which unfortunately will have to be lengthy to understand the problem.
The compressor in my Carrier model 38TRA042310 condenser failed after about 16 years of service. I guess that’s not unusual for Tucson, AZ. The solution was to replace the compressor if one could be found. The technician called me later in the day and told me there were none to be had in the local area. The alternative was to replace the entire outdoor unit with a dry R22 unit.
The repair crew showed up with a Rheem model 13AJA420175. During the installation numerous errors were made; too numerous for this post, but the one that disturbs me the most is that they didn’t use a micron gage during the evacuation of the system. They relied on the manifold gauge which I later found out is old school. The technician didn’t have a scale so he just basically charged the system until it blew cold air. He admitted that he didn’t know how to do this and recommended that I have the charge check by one of their more skilled technicians.
The more skilled technician found that the system was overcharged and reduced the charge as much as he could. In the end the suction pressure was about 62 psig. The suction line temperature was about 51 degrees. For what it is worth the indoor temperature was about 76 degrees and I would guess the humidity was around 50%. The outdoor temperature was around 85 degrees F.
What bothered me was the head pressure of 250 psig. According to the chart on the unit, the head pressure should have been around 203 psig. The delta T was around 19 degree F and I was cool again. If I were an average consumer I’d be as happy as a (insert your own simile), but I read enough in books and on the Internet and I’m not happy.
I realize that it would have been more rational to replace the entire system and upgrade to a 410a system rather than pay $ for this repair on a 16 year old system. Nonetheless when the outdoor temperatures are still above 110 who can be rational? Still I want this repair done right.
I wrote the manager and told him of my concerns. He finally gave me a call and told me he wanted to consult with the last technician and that he would get back with me. It has been sometime and I think he may be trying to blow me off. I’ll have to call him. Anyway before I talk to him again I’d like to know where I stand.
He’s is probably not going to offer to evacuate the system and recharge as this is an expensive procedure. I suspect that he will tell me that the high head pressure is due to preexisting restrictions in the rest of my system. So the question remains: Is there way to determine the cause of high head pressure between non-condensables in the system versus some sort of restriction?