More Air Conditioner questions

[Dan Hintz]

Okay, maybe just one (since we're already talking about it in Off Topic...

Several years back had a new 23 SEER heat pump installed to replace the ancient one that leaked like a sieve. It cools fast, warms quickly, and has a highly programmable controller with the option to add zoning (which I will be on the next remodel attack).

The problem comes around during season changes... the cooling side of things has difficulty getting going at the very first part of the summer. The last two (three?) years I have turned the temp down and received barely cool air (like you would get while sitting in the shade of a 100 degree day). The house will climb to 80 before we go to bed, with the stat set at 72, and while it runs, the air temp is barely cooler than ambient.

So the repair man is called out (to the tune of $100)... and he finds nothing wrong with it. Freon is up to pressure, compressor and cap is good, etc. He's usually there about 30 minutes, and before he leaves it will always blow cold air. I watch him like a hawk. No freon is put in the system, just a gauge check is done. I never see him disconnect/reconnect anything, push a reset button, etc. But two years now it has ended the same. Now that temps are starting to climb, I'm afraid I'll end up in the same boat yet again. Note, I do not think the repairman is bamboozling me for money, but I cannot logic out the problem yet as it happens so infrequently (once a year), and my desire to live in a comfortable environment overrides my desire to suss out the real problem in the meantime.

I'm tempted to see if it happens again, turn off the breakers for a while, see if that does it. Maybe something is sticking in the digital thermostat's memory that requires a complete loss of power when switching from "heat" to "cool"... if I can prove it, maybe I can get them to warranty the stat and replace it. Frustrating, though, and when you're losing sleep at night due to uncomfortable temps, it doesn't help matters.

Anyone seen something like this before?

[Mel Fulks]

It's clear from your question that your Knowledge on this exceeds mine, but we had a problem where unit was working well
in only one direction . Turned out to be some extra valves found on the high seer units and it ruined the compressor . Our
trusted service guy took out two valves and said it would cost us one seer, but we have not seen any difference on the bills.

[Mike Lassiter]

Dan I put a Fujitsu mini split heat pump system in the shop our laser and embroidery machine is in about 3 years ago now I think. The unit I got has a SEER of 26 ( I think - it was "off the scale" on the yellow energy guide label that comes with appliances) and has a remote control that operates it. I set it to whatever temp and it maintains that. If it needs cooling like it has gotten hot during the day, then I get cooling inside. If it cools off at night and needs heat it automatically changes to heat to maintain the desired set temp (within 4 degrees I think). It cut our heating cost in half over the heat/air unit we installed when we built the building for the laser. It was like a window unit a/c that had electric strip heat added. Fan ran 24-7 on heat mode, but on a/c mode the unit cooled down and shut off. The fan came back on about every 5 minutes to do a air temp sample and would either shut back off, or turn on compressor and run till cool again. The mini spilt system I have I doesn't allow multiple inside units as it is rated at 18,000 btu's I think but they have a larger outside unit that can do like yours. I LOVE mine. Scroll type compress - DC inverter technology that basically never turns off, but will power down to nearly nothing when not needed.
Ok with all that said, so far my unit has functioned flawlessly. We had cool nights and warm days these last few weeks. Calling for frost warning in a night or two with the temps to get into low 30's upper 20's range yet it has been in the upper 70's and low 80's some already here. I feel the unit you have operates the same way, and automatically changes function depending on the need rather than you having to change the function manually. If that is right, I don't really know what to say either. I would think with the vast weather temp swings we have had so far your unit likely would have already had to switch modes to cooling a day or so already. Mine has. That's one thing I really like about it. Old unit was manually controlled so if it was cool at night but got hot during the day when I was at work, it might get too hot for laser to be happy. This unit gives me a great deal more piece of mind in that regard.

[Jerome Stanek]

Make sure the heating element is not kicking on due to stuck contacts.

[Brad Adams]

Do you have an IQ drive heat pump?

[Lee Schierer]

It sounds to me like the crossover valving is not changing with the seasons. It may be sticking and all the repairman does is tap on it and it switches so then it works fine.

Added: Here's a schematic of how hat/cool systems work. 1278s.jpg

[Dan Hintz]

I enabled cooling mode a few days back, and that same night the air coming out was the expected barely cool... to be fair, it was only trying to cool 2 degrees, but still. It turned on earlier today to keep the house from rising above 75, and the air was nice and cold. It's as if this thing is a cranky old fart that needs a few days to remember what it came in the room to do. I guess I'm good for another year

[Dan Hintz]

It sounds to me like the crossover valving is not changing with the seasons. It may be sticking and all the repairman does is tap on it and it switches so then it works fine.

Sounds like a very real possibility... I will check into this. Thanks, Lee.

[Brad Adams]

What brand of heat pump is it?

[Dan Hintz]

What brand of heat pump is it?

Carrier Infinity

[Brad Adams]

I thought it may have been a Nordyne product as they are the only company with a 23 seer heat pump. Carrier has never had a 23 seer unit. Unless it is a mini-split system.

[Dan Hintz]

I thought it may have been a Nordyne product as they are the only company with a 23 seer heat pump. Carrier has never had a 23 seer unit. Unless it is a mini-split system.

Sorry, I mis-spoke... 21 seer (20.5, if you want to get detailed).

[Mike Henderson]

This is somewhat of a hijack, but for anyone who knows air conditioners, which high SEER 5 ton A/C unit would you recommend. I don't need a heat pump because we use gas around here (cheap) and it rarely gets cold - we only use heat a few times a year.

I've been wanting to change out my 13 SEER A/C for something above 20 SEER but I don't know which ones are good ones.

Mike

[Brian Elfert]

Heat pumps work very well for areas where you don't need heat very often. They can cost less to run than gas heat, but you need to talk to a local HVAC company.

More important than equipment brand is the quality of the installation. A crappy installer can make a top of the line furnace perform poorly. Sizing of the equipment is also very important. Your installer should not just put in the same size equipment without verifying the equipment is properly sized. Often times the last installer may have put in the wrong size equipment, or changes in equipment mean you can get by with a smaller unit. Properly sized equipment will keep the temperature more consistent in the house.

[Bill Cunningham]

I was going to suggest the reversing valve (crossover valve?). I have a infinity system here as well. If the valve is not working right, you may also see a problem when it switches to heat, or goes into defrost mode. Mine gave me lots of problems when first installed. The first January they came and removed it and took this big block of ice back to the shop to replace the valve for the second time. The first time it was replaced on site, and I'm pretty sure the service guy burnt it while soldering it in. It took a full two years before they finally got it working right. The only thing original is the case and the coils. Everything else was replaced.