Regular Guest
I have two quotes from Carrier (plus others) and noticed that the Carrier A/C that was recommended in both is a two stage (my preference for comfort) with reciprocating compressor vs. scroll.
My understanding is that the reciprocating compressor can run more at 50% and full output while the scroll is 70% and full. I like that for my climate.
The reciprocating pump must shut down to change stages. I don't like that. (Is is momentary or 5 minutes?) (How does this work with the Infinity?)
The scroll is supposed to be quieter (noise/location is an issue).
The scroll is more efficient and more expensive.
Is the reciprocating two stage model an old part of the product line?
What about reliability? We owned a 2001 model two stage 18? Seer Carrier with a scroll and it leaked down frequently. Has that been fixed or did we have a lemon/install problem?
Thanks for any insight.
Global Moderator
The scroll is effectively between 75-80% capacity on low. So your low capacity isn't that much less than your high. The Bristol TS is much lower on low so there is quite the difference. The Bristol has been out longer than the unloading scroll but right now, Bryant/Carrier is the only one still using it.
Scrolls don't leak, coils do. Manufacturers are trying to improve on their quality to avoid this.
Professional Member*
Originally Posted by thunderbirl
The two speed reciprocating compressor has had a history of starting issues in that line of units. Though it has supposedly been corrected, I'd recommend going with the scroll. The Infinity stat (UI) and variable speed blower must be used with the two-speed scroll to prevent coil freezing.
Last edited by hvacrmedic; 01-24-2009 at 11:15 AM.
Professional Member*
have you looked at trane the new 20 i has 2 recip compressors 1for low and 1 for high
Professional Member*
Or have you looked at the best the Nordyne IQ drive? check out the new Frigidaire
a/c & heating products for both "warranty" and comfort there unbeatable.
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Membership Committee*
Twilli has a few 10 seer units for sale
No Heat No Cool You need Action Fast
Professional Member*
Hey you still have some of those 10/10 Coleman's? there 10 seer and 10 eer right?
__________________________________________________ _______________________
“Experience is a hard teacher because she gives the test first, the lesson afterwards" ~ Vernon Law
"It's what you learn after you know it all that counts." ~ John Wooden
"When the teachers become unteachable we're all in trouble" ~ Mr. Bill
"Remember "Pro" is only a name, it's not always a mindset determined to do everything correctly" ~ Mr. Bill
Professional Member*
The two stage scroll is a waste of time IMO. So little unloading - why bother?
The shut down between stages will disappear from your consciousness, unless you're one to dwell strangely on things that don't matter.
I'd look at published decibel ratings. Typically on high end equipment like this they utilize compressor jackets, sealed compartments or whatever to minimize noise. I don't know specifically about the Carrier product. But at that price point Carrier knows full well that you expect quiet.
The scroll may or may not be more energy efficient than the recip. But the unit as a whole is the SEER/EER rating that it is. How they get there is not particularly relevant. An 18 SEER system with a scroll is no more efficient than an 18 SEER system with a recip.
Two stage recips are a proven technology. A local church I service has a half dozen of them from over 20 years ago. Only one has gone bad. There's very good reason to believe it went bad because of installer/user issues. Make sure the installer does it right. There are a lot of things to do right. Check the first link in my sig.
Professional Member*
I can't speak for your 20 year old units that are non-Infinity systems. The OP on the other hand was specifically inquiring about the Infinity recip vs scroll. Because I sell these, and have experience with them, and the service bulletin, I recommend the scroll. HTH. Let me add that the board has been upgraded twice. The first upgrade didn't seem to do the trick. The lastest upgrade is considered to be a permanent fix to the problem.
The compressor itself is a perfectly good compressor. But a compressor is at the mercy of the engineering built up around it.
Last edited by hvacrmedic; 01-24-2009 at 06:01 PM.
Professional Member*
Very helpful. Thank you.
Quality is an interesting topic. A lot of people include features in their discussion of quality. However, that a unit is quiet (a feature) or not has no bearing on how long it will last. So I boil down the issue of quality to this: How long will it last? On that count there is simply no objective/scientific proof which brand (or compressor for that matter) is better. Period. Some have certain features that others don't. But quality differences? Absolutely unprovable.
On a related note, every manufacturer will have a run of bad units. We generally don't know they had that run till long after bunch of them went bad.
New technologies are the same way. Unloading scrolls haven't been around for long compared to two-stage recips. Naturally we expect they'll wear just fine. But we don't have a track record for them like we do recips. For all we know there may come a time when unloading scrolls start dropping like flies.
As for the circuit board, an easy fix once identified - which is why I thanked you for the insight as to the nature of the problem. A mechanical issue with the compressor takes a lot of retooling and testing to fix. Changing a few resistors and/or chips is a snap, especially when you make your own boards as I think Carrier does.
As you say, that's just one opinion. It applies nicely to this thread, non-Carrier equipment notwithstanding.
Membership Committee*
Twilli says were is SlapDash when you need him
No Heat No Cool You need Action Fast
Professional Member*
I didn't see the added second paragraph till after I made my last post.
There was no presupposition whatsoever. I was speaking generically about two stage compressors. Though the OP is looking at specific models, his question has the definite appearance of generality - that is to say, the general topic of recip versus scroll. So I answered generally. My original post made no reference to your specific points. If it seemed otherwise, my mistake.
Professional Member*
I removed the details of the service bulletin before seeing your reply. I didn't think that kind of info really belonged in the resi forum. Anyhoo, FWIW, "if" the board defect has truly been corrected, then it really wouldn't matter which compressor you used, it would depend upon the indoor unit that you wanted to match to it, and on preference. And just a little note for the OP: The variable speed blower and the Infinity stat (UID) must be used with the two-speed scroll to prevent evaporator freeze-up problems in low stage cooling, because it doesn't unload to 50% like the two-speed recip does. So if you go with the scroll make sure the installing contractor is aware of this. And FWIW, besides the occasional glitches here and there, which can always be remedied under warranty if you should happen to experience one of them, the Infinity truly is a fantastic system. As for leaks, well that isn't a standard feature, but again, that's what the warranty is for. I recommend getting extended coverage, 10 yr P&L. No worries for 10 yrs, definitely worth the extra $.Very helpful. Thank you.
Quality is an interesting topic. A lot of people include features in their discussion of quality. However, that a unit is quiet (a feature) or not has no bearing on how long it will last. So I boil down the issue of quality to this: How long will it last? On that count there is simply no objective/scientific proof which brand (or compressor for that matter) is better. Period. Some have certain features that others don't. But quality differences? Absolutely unprovable.
On a related note, every manufacturer will have a run of bad units. We generally don't know they had that run till long after bunch of them went bad.
New technologies are the same way. Unloading scrolls haven't been around for long compared to two-stage recips. Naturally we expect they'll wear just fine. But we don't have a track record for them like we do recips. For all we know there may come a time when unloading scrolls start dropping like flies.
As for the circuit board, an easy fix once identified - which is why I thanked you for the insight as to the nature of the problem. A mechanical issue with the compressor takes a lot of retooling and testing to fix. Changing a few resistors and/or chips is a snap, especially when you make your own boards as I think Carrier does.
As you say, that's just one opinion. It applies nicely to this thread, non-Carrier equipment notwithstanding.
Professional Member*
I appreciate that medic.
Regular Guest
You can't tell the difference.
.
Professional Member*
I'll second that. I was working on one with the Bristol recip just a couple days ago and had to look at my gauges to see whether the compressor was actually running. I couldn't hear it, period, just the fan.
Professional Member
One thing that I have noticed on this site is EVERYBODY has informed experienced oppinions. I have read that scrolls are better than recip because 10 people have 200 of em installed with no problems, etc, and that 20,000 recips have been runing for 30 years installed by Shophound with no problems. I'm kidding a little there..
As an X Master Mechanic, I'll say all car's and trucks are junk. I dont care if it's a an old AMC or new infinity or Lexus, they all have their issues.
You buisness is no different than others, if you only worked on\selling Ford's that is what you promote.
Is their an unbiased oppinion about recip\vrs scroll or any brand of manufacture on this site?
Read humor here folks........Most of us know the answer
Regular Guest
Infinity 2-stage recip heatpump cranking away next to my master bedroom. Can't hear it. I do hear my neighbor's Goodman unit that's 3 doors down 'though.
Professional Member*
One thing that I have noticed on this site is EVERYBODY has informed experienced oppinions. I have read that scrolls are better than recip because 10 people have 200 of em installed with no problems, etc, and that 20,000 recips have been runing for 30 years installed by Shophound with no problems. I'm kidding a little there..
As an X Master Mechanic, I'll say all car's and trucks are junk. I dont care if it's a an old AMC or new infinity or Lexus, they all have their issues.
You buisness is no different than others, if you only worked on\selling Ford's that is what you promote.
Is their an unbiased oppinion about recip\vrs scroll or any brand of manufacture on this site?
Read humor here folks........Most of us know the answer
That might be true for some, but I really like the Infinity. As for the rest of the stuff that Carrier sells I don't get excited about it. It's just standard stuff, the same thing made by every other manufacturer. There have been some models of Carrier units that I despise. Conversely there are some brands that you will never hear me talking good about. And FWIW we sell more than Carrier. Lennox for instance, I don't like anything they make except the XL19, but compared to the Infinity the XL19 is just "so so". The Infinity is way ahead of the pack. I'd say the same thing if I had never sold a single one of them.
Last edited by hvacrmedic; 01-27-2009 at 12:31 PM.
Professional Member
vrf units. I am a Carrier dealer but I feel all our american mfrs are behind the curve on modulating equipment. I have installed the Mitsubishi and Fujitsu units and have been extremely impressed. They do not fit in all retro apps as they can't handle much static but if you can or have the right ducting to put these in, they are I feel the best thing avail. Quiet!! super efficient and very flexible. The one thing I don't like is their thermostat controls. They are still from the other side of pond and most people do not like them. It is great although to sit outside and listen, hard to hear the unit as it mods down to 20% almost no fan and compressor running real slow and then you will hear a slight purr and up in capacity as another air handler kicks in. Pretty cool. Ps, I really like the infinity system but what I really want to see is the infinity with vrf condensing unit, that would be purrrfect. I have heard that Carrier is working on VRF unit for their lineup, not holding my breath but am dreaming.
Posting Permissions
Reply