Repair or replace HVAC

[Radiant heating newbie]

hi,

I had a service tech come out and did routine servicing on Monday April 11, 2022. He did some pressure tests with covering the top to fake out a higher temp. Mechanically the AC which is a RUUD was working fine. Outdoor temp was just a bit under 50F. He mentioned there was a leak. He then showed me the readings. It was a reading with no covering on top and the unit was running. Blue side 47.3 psi and Temp 23.6 and the Red side 111.1 psi with temp at 64.9. Does the outside temp affect that reading? My understanding those numbers is pointing to some issue and could be refrigerant. If the refrigerant is low then should I have a company pump some refrigerant and check for leak. The refrigerant is R22 and the AC is eighteen years old.

Should I get a second opinion and get a leak test with an idea that there might be a repair or should I start looking for a new HVAC unit? This is the old dilemna of repair versus replace. If this was a car I know exactly what I need to do depending on make, model years etc etc . The HVAC never gave us a problem before. I have been on this property for twelve years. This is out of my expertise.

Thanks for the help.

 

[WorthFlorida]

Outside temperature does affect the pressure readings and each unit has a chart for ambient temp & pressure readings. To know if there is a leak a refrigerant sniffer needs to be use. Most leaks, if the unit is still cooling is on the low pressure side of things. It could be the line or the evaporator coil inside the air handler. If it was on the high pressure side it would be empty of refrigerant.

R22 is officially banned from import and hasn't been been manufacture in the USA for over 20 years. Inventory is allowed to be sold but it is extremely expensive. On line it's averaging over $35 a pound and AC service companies may charge five time more per pound to "top off" your system. If the tech added refrigerant it just would leak out if there is one. AC techs now use a scale when adding refrigerant to any system, even a new one. Refrigerant of any kind is the most expensive component in AC maintenance. Most techs do not like to add refrigerant when the temps are below 60 degrees since it could be over charged and then blow a leak when the temps reach 90 degrees. A good tech will usually suggest another visit when the temps are much higher.

Leak or no leak, time to replace it. Yours is maybe a SEER 12 being 18 years old. Minimum now is SEER 14 and SEER 16 is easily affordable over SEER 14. Above SEER 16 is gets expensive. Your cooling electric bill will be lower, the humidity levels inside the home will be lower and depending how you're set up using gas or fuel oil for heat, a heat pump could be a better choice. Electric rates stay fairly steady as compared to fossil fuel. The heat pump would be the primary heat as the existing heating system would be the secondary.

I like to use an analogy, "putting new tires on the 53 Oldsmobile is still a 53 Oldsmobile".

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[Radiant heating newbie]

Thanks for the reply! This is a flat roof install so the heat pump would be an air one? However I have a radiant heating system as primary source of heat and the hot air furnace is a secondary backup. So what are everyone's thoughts on modulating ac? I heard the Ac make is not as important as the actual install itself is that true?

 

[Fitter30]

Both inside and outside temps will effect readings. The gauge reading unit short of refrigerant. Brand of equipment isn't as important as the contractor. The higher the efficiency of the equipment the more qualified the service people have to be. They need factory training, might need a laptop with the correct program and availability for updates. Parts are more expensive ( out of warranty) and there are more printed circuit boards in units. Check with your utility companies for rebates. Your existing unit is probably 10 seer.

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[ArayT]

An eighteen year old unit with issues should be replaced. The cost of the repair and then if you have another issue its money down the drain. I would get three prices on the replacement from reputable companies and make sure you compare apples to apples. The higher the EER rating does have a payback but based on price difference could be many many years down the road i.e. difference between 14 SEER and 18 SEER payback may be 20 or more years. I personally would not recommend anything with a payback more than 8 years. Good Luck!

 

[Radiant heating newbie]

Well things have changed. I brought a second tech in to check things out. He basically went to both areas roof and garage and basically said its not leaking any refrigerant. The first tech was from a different company. When I questioned about the refrigerant being low to the first tech he broke out in a big time sweat. I have some buddies of mine where 40 degree weather is a heat wave and they melt but this fellow looked like he was nervous. In any case neither of the techs are like the pros on this website. Btw I have been to other websites but for some reason Terry Love plumbing site also is a great HVAC site. I think all of you are the tops in the country. I think now its a matter of letting it run or doing a planned replacement which I am leaning to. I was getting into all of the superheat calcs and I stopped due to it being way more complicated to get into. Well thank you again and I have learned a lot and will make a decision. Also one estimator took one look and felt it was too expensive to replace due to needing a crane. The other two were great they came in and did load calculation. They found out what I suspected I don't need a 4 ton hvac but something smaller. Since its smaller no need for crane.

 

[Fitter30]

With pocket style thermometer take a reading at filter and 18" from the evaporator coil. Readings should be 18 to 24° difference with most systems run 20° + or - 1°. With system with a load the suction line ( insulated line) should be cold.

 

[Fitter30]

Most companies would repair refrigerant 22 systems. The refrigerant would cost u $120+ per lb. New system new line set unless it's buried in wall or ceiling. If they use the old lines they have to flushed with the.proper solvent. Contractor is more important than unit brand.

 

[WorthFlorida]

...........The other two were great they came in and did load calculation. They found out what I suspected I don't need a 4 ton hvac but something smaller. Since its smaller no need for crane.

A few complaints you'll occasionally read is about down sizing is "after replacing my AC unit, the house won't cool, as the old one did, when it gets over 90 degrees". They are usually ticked off since after spending $5k or more. Usually the problem is most northern states AC cooling temps are kept at a lower temperature such as 72º when the outside temp gets over 90, as stated on another post, the AC temp for under five ton residential units drop the temperature about 18º. when its 80º and muggy, keeping the AC temp to 72 is usually doable. But when it is over 90º, the house temp may not be able to get below 77º. This is where the complaints start and the poor AC tech get the abuse. "AC is working just fine as designed".

Old units were oversized to compensate for a poor insulated house, non e-glass windows, etc. and the extreme hot days. The load calculation is necessary for a well designed system. My current two story home, 2475 sq ft with one AC unit on the second floor is a 3.5 ton. I have a well insulated home and tinted glass for the sunny windows and the unit performs just right. My last home, similar is size in South Florida, had two units and two 2 ton units could not handle the heat. I had to up the second floor to a 2.5 ton. Lots of glass.

I'd be interesting to know the size determined by the heat load calculation. I would expect 3.5 ton. If a 3 ton is suggested please review the contract and as to what happens if the new size cannot handle the heat load. I would also suggest to replace the unit ASAP for pricing. Everything is going up and if the unit quits in the middle of the summer during a heat wave, it could be days to get a new unit in when everyone is very busy. In Florida it is not more than a day or even the same day to have a replacement installed, not sure about NJ. BTW, when I read that the tech covered the compressor coils to simulate a hot day, no way. Not sure how he came up with that.

 

[Radiant heating newbie]

A few complaints you'll occasionally read is about down sizing is "after replacing my AC unit, the house won't cool, as the old one did, when it gets over 90 degrees". They are usually ticked off since after spending $5k or more. Usually the problem is most northern states AC cooling temps are kept at a lower temperature such as 72º when the outside temp gets over 90, as stated on another post, the AC temp for under five ton residential units drop the temperature about 18º. when its 80º and muggy, keeping the AC temp to 72 is usually doable. But when it is over 90º, the house temp may not be able to get below 77º. This is where the complaints start and the poor AC tech get the abuse. "AC is working just fine as designed".

Old units were oversized to compensate for a poor insulated house, non e-glass windows, etc. and the extreme hot days. The load calculation is necessary for a well designed system. My current two story home, 2475 sq ft with one AC unit on the second floor is a 3.5 ton. I have a well insulated home and tinted glass for the sunny windows and the unit performs just right. My last home, similar is size in South Florida, had two units and two 2 ton units could not handle the heat. I had to up the second floor to a 2.5 ton. Lots of glass.

I'd be interesting to know the size determined by the heat load calculation. I would expect 3.5 ton. If a 3 ton is suggested please review the contract and as to what happens if the new size cannot handle the heat load. I would also suggest to replace the unit ASAP for pricing. Everything is going up and if the unit quits in the middle of the summer during a heat wave, it could be days to get a new unit in when everyone is very busy. In Florida it is not more than a day or even the same day to have a replacement installed, not sure about NJ. BTW, when I read that the tech covered the compressor coils to simulate a hot day, no way. Not sure how he came up with that.

Thanks for the reply. It's a 3 family wood construction row house in a city.I live in the bottom unit. We have 1200 sq feet of livable space with an entire building butting up against us on one side. Exposed in the front and back to the outside. Another conidtioned unit space above us. The other side is partially to the outside due to a setback to get some windows in. We have another 600sq ft space in a walkout basement. Since it is below grade it is always cold in the winter and cold in the summer. It just needs a dehummidifer to be running and it's very comfortable. One estimation was for a 3.5 ton unit and the second estimation was for a 3 ton unit. Currently the AC is running fine with no issues. We are thinking we can get through the summer fine. Worst case we will camp out downstairs. That downstairs area really does not need to be air conditioned. Then we might have a planned replacement in the fall or late winter of 2023. My better half was adamant on not getting a new AC if everything is working. Happy wife happy life. I did show her the expert opinions on this site and she changed her tune and was fine for a planned replacement. hey, WorthFlorida I like your quote "The wife is still training me". I personally like machinery last as long as it can in good working order with good maintenance. Burns me up that I got duped by one tech and took everyone's time on this website on a good working machine.

 

[Fitter30]

Contact your electric company see if they offer a energy audit that has a blower door test. This test tell home tight the house is. Bottom floor space 2- 2.5 tons of cooling.

 

[Radiant heating newbie]

hey Fitter30. I did have a private energy audit person go through the property two years ago. My property was too strange to do an blower test. My front door goes to a lobby. If I recollect correctly the property was pretty well insulated. There was not too much they can do. I did have one company do some insulation on the sub basement. I have a subbasemet and behind it was a standup hallway that went to a light shaft of all things. In any case they put on that exterior wall proper basement exterior insulation. There are other strange spots where I put up rock wool. They were ok with it. Overall in decent shape for insulation. I had the same company come to my mother's house. They did do a blower door test. The end result overt there on that property the attic areas were air sealed. They put in baffles and then blew celluose insulation. Big difference for the house in the summer and winter. My property though is in decent shape. I could not find the report to give you any proper numbers.