Home AC Pressures

[Gerald K4NHN]

It HOT here in SC and I was cleaning the condenser on the outside unit yesterday. I decided to look at the pressures and see what they were...

The evaporator is inside a closet with the water coil that heats the house.. The Temp here is 95 degrees and humid, The low side is 60 pounds and the high is 200. The low side has a little moisture on it but not much. The drain has a steady drip drip, drip.... It runs most of the day and starts cycling late at night and does this until mid morning....

I've done a fair amount of work on car AC, and l know what to look for on pressures on them, but not on a home unit. I was thinking that these pressures were on the high side. I also did replace the filter.

I haven't clean the evaporator yet because of where it at.

Any suggestions or am I OK

[Dr. Hardcrab]

Bottom line: If you have not had the unit serviced in some time, it might be a good idea to call a reliable service company to check it out. Ask your friends and neighbors who they use.

[BGBevill]

Tough to say from a keyboard, but I don't think your pressures are high at all. I am in SC and we usually see high side pressures higher than that on these rather warm days on all but the super efficient systems. You really haven't given enough info to say anything with any degree of certainty, but if it has been a while since the unit has been serviced it might be a good idea to have it done soon.

Bobby

[Gerald K4NHN]

Thanks for the input... I was more concerned about the low side pressure.. I'm accustomed to seeing pressures in the 30's on cars with R-12, and the temps out of the vents in the 30 to 40 degree range, which is what I'm set up to service.... pump, reclaim unit, reclaim tank, gauges, oils, R-12, digital scales.... Just haven't done the R-12 and home unit.... I've always just kept the condenser cleaned, the fan and blower oiled and blades cleaned, and the filters replaced. I did spray the evaporator and clean it a couple of years ago. The unit is about 8 years old now...And that can't be good the way things are being made these past several years.

You guys try and stay cool. Gerald

[gerry]

My first suggestion would be to be sure you have a proper EPA 609 certification. The feds take that fairly seriously and connecting gauges requires an EPA certification.

My second suggestion is don't assume MVAC (motor vehicle) systems operate in any way similar the HVAC (such as home) systems. They use radically different control systems and different refrigerants.

Finally, pressures by them selves mean little (except in extremes). Superheat or subcooling are the important metrics. Generally, this data is supplied by the manufacturer in a chart or graph form to cover different operating conditions.

gerry

[CBHVAC]

So..you have a MVAC card...and its not the correct card to service units...

Your home unit does not use R12...

Really? Humm...whatever..I have to go service a few 10 year old units...I will be sure to tell the homeowners to change them out right now..