View Full Version : Heat pump condenser: Desperately seeking opinion!
03-20-2008, 11:09 AM
Hi, all. We have a condo at the beach, and the heat pump condenser unit on the rooftop needs replacing. I am told that in 2020, the rules are that these units will need to use a new type of freon, 410A. And that as of 2010, they will stop making the units that work on R22, current type of freon.
Several places we have contacted have told us that at this point, it is fine to just go with units that use the current type of freon, R22. Especially since we are not able to afford replacing our 2-ton HVAC unit, which is about 18 years old. He says that that unit has lots of life left in it, cause it's easy to replace the fan motor.
We are looking at an American Standard heat pump condenser right now, which is the best price. Other companies have told us they use a heat pump condenser that has a "special coating" to guard against salt air. The American Standard guy says that while his doesn't have a special coating, it is made with the same type of metal inside (as opposed to kind made with two different ones, which could lead to rusting).
What I need to know is: 1) whether it's fine advice to go with a unit that works on R22. And 2) whether it's OK to get a unit without special coating to guard against salt air. THANK YOU for any opinions.
03-20-2008, 11:46 AM
AmStd and Trane use to advertise their outside split condenser units with "full coil protection with seacoast shield". My old AmStd product literature does not show this description for package units. I would ask your dealer about this and any other third party coating that might be effective for a coastal environment that does not effect performance/efficiency or void any manufacturer warranty. Both the Trane and Am Standard area distributor usually have a residential specialist on their staff-you could contact them as a resource.
As far as R-22 vs R-410, I prefer the R-410 for HPs but if this is strictly for AC, I don't really believe it matters as much at this time.
03-20-2008, 12:22 PM
The heat condenser unit is for an HVAC that delivers air conditioning AND heat.
03-20-2008, 01:08 PM
It would be a big mistake to replace just the outdoor unit and keep an 18 year old indoor unit. The coil in that unit was meant for your current heat pump. They don't interchange. At best you will have compromised capacity & efficiency. At worst you'll have to change refrigerant level to switch between heating & cooling and put increased stress on the compressor. Personally we would refuse the job, we don't want the headaches of such a hack up and liability if the compressor dies in short order.
The all aluminum coil in the American Standard outdoor unit makes it better for salty air than the 2 metal of most coils, copper tube & aluminum fins.
03-20-2008, 01:39 PM
I misread your post. If you have both an outside unit as well as an inside air handler, then Am Std is a very good choice. Follow Baldllonie's advice and replace both so you will have a matched system. And I would change over to a R410 refrigerant model.
03-20-2008, 02:02 PM
The R22 refrigerant is fine to use.
If you want anything close to the rated efficiency, replace the ID unit also. Or you could have troubles like baldie said.
03-21-2008, 09:56 AM
BaldLoonie, here's the thing: We are not up for springing to replace both the rooftop heat pump and the indoor unit. Especially since it seems that indoor unit has life left in it.
The trouble with switching to 410 freon is that the lines that run from the rooftop to our house, I am told, would have to be replaced because the old freon (22) would still be in the pipes. And that is not something the condo building would pay for.
I am unclear why an American Standard rooftop heat pump that uses R-22 would be a mistake to use with an indoor 18-year-old heat/cooling unit--surely the current rooftop heat pump uses R22?
03-21-2008, 11:51 AM
Even though they are 2 pieces, they are a matched set. It would be like buying a new car but putting your old transmission in it. Will it drive? Yes. Will it be smooth & efficient? No.
The indoor coil and metering device are designed for the machine on the roof. 18 years ago, that could be 8 SEER. Put today's 13 SEER unit on the old coil and there will be a loss of efficiency & capacity. Today's equipment wants much larger coils. It may be such a mismatch that you will have to remove refrigerant in the fall in order to heat and have to add it back in order to cool.
As I said, we would refuse to do this work. We do not want the headaches. We clean up messes like this all the time. If this were an A/C, you'd probably be OK, just loss of performance. Being a heat pump, you may regret it but go for it and keep your fingers crossed.
03-21-2008, 11:55 AM
Being a heat pump, you may regret it but go for it and keep your fingers crossed.
They will regret it.
03-21-2008, 12:11 PM
You cant beat American Standard/Trane on the beach, no coating applied to a copper tubing coil will make it compare, dont buy that sales pitch.
Mismatching here is rampant, as condensers must be replaced every 5-7 years, 1 air handler may be attached to 4-5 or more condensers in its lifetime, but when going to a 13 SEER its best to bite the bullet and change the air handler as well, its not a matter of it still having life left in it, but of being compatible with today's equipment.
03-21-2008, 01:40 PM
If you decide to keep the 18 yrs old AHU (indoor unit) you will be taking a big risk especially going with a heat pump. In heat mode that new condenser(roof top unit) will be producing plenty of heat which means the refrigerant in the evap coil will be under very HIGH pressure, the 18yrs old evaporator coil may not be in condition to handle that. The result will be Refrigerant leaks that will harm that new condenser.In cooiling mode the old indoor unit evap coil (indoor radiator) may not match up correctly with new condenser, that may lead to flood back of liquid migration which will also damage the unit.
R-22 is being phased out, but that does not mean its gonna disappear from the face of the earth if budget is an issue I would chose R-22,however get some estimates you may find it cheaper to get R-410a. If you decide to change both systems look for units with rebates from manuf & also take advantage of power company rebates & IRS tax credits. This may help a bit with the "INVESTMENT" of a new system, keep in mind a full new unit can be as much as 30% more eff.it can have a big inpact on your power bill.
03-21-2008, 02:09 PM
American Standard does not recommend the installation of a new 13 SEER or higher efficiency product on an existing air handler(Indoor Unit), especially one that is 18 years old.
The 18 year old system probably operated in the 7-8 SEER range with a smaller indoor coil and piston or cap tube metering device. The newer 13 SEER and greater systems require a larger indoor coil with an expansion valve type metering device for proper operation. The coil volume ratio(amount of refrigerant the indoor coil will hold compared to the outdoor coil) should be as near a 1:1 ratio as possible to maintain proper charge balance between heating and cooling.
This coil volume is critical for proper operation and you are risking the integrity of your new outdoor unit.
Ask the dealer to provide you documentation from American Standard that states that this practice is acceptable.
American Standard Position Statement from publication number:
American Standard recommends installing approved matched indoor and outdoor
systems. All American Standard split systems with a nominal rating of 13 SEER and
above are listed in the ARI Certified Directory with thermostatic expansion valves
New Outdoor/Existing Indoor:
Contact American Standard to
assure indoor and outdoor coil
volumes are in range
The dealer will be unable to provide any information from the Application Engineers or Field Service Representatives that will deem this as acceptable practice.
03-21-2008, 02:11 PM
The system double posted my response!
03-21-2008, 02:48 PM
The system double posted my response!
Yea but it was a good response ! :D
03-21-2008, 05:45 PM
I'm ashmed to say.
But i once did a Condenser changeover w/o changing the very old Inside Carrier AHU.
The Home Owner insist on just changing the outside unit only. he say he could not afford it. I felt sorry and in need of some money too. so i did it. before other HVAC company would come in and do it.
What a mistake.
It was like groundhog day movie. The unit never work right.
1.5 years latter he called me and decided enough with this nonsense.
and change the inside AHU too.
He never call me back for any problem anymore :D
a new Outside unit with a 18 years old AHU is just going to be a PITA.
Find a way to finance it.
You be glad you did it.
Somebody else say it already. You won't want a new car with your old transmission. :)
03-21-2008, 09:50 PM
Where are you located?
Second. It is not mandatory to replace linesets when switching from R-22 to R-410A. It is recommended. As long as the lineset is the correct size, and properly recovered then you shouldn't have any problems.
And I agree with everyone else. Get the entire system. Probably would want to look into ductwork as well. Maybe zoning, air quality, etc...
Remember, HVAC is not an expense. It is an investment. Yes it costs a lot of money, but in the end, it all works out.
If you want quality, you have to pay for it. If you want cheap, you will regret it.
03-22-2008, 01:31 PM
When the newer, higher seer equipment first hit the marketplace, the manufacturers allowed a mismatch as a short term solution in emergency. They all sent out positions stating this, with the expectancy that the indoor unit would be changed asap. The mismatch can cause compressor failures due to reduced flow of refrigerant through a fixed metering device on an old coil as opposed to a new larger volume coil with a tx valve. The reason for this was the ability to to provide eneough equipment in a timely fashion. Some contractors who do not work directly with a particular product line have not seen any of these notices, and assume its okay to do a mismatch. All of the posts above tell you the right thing. We do not know your financial position, but a lot of people tell us they cannot afford to do it the right way because they think we are trying to sell them something they dont need. You really should install a whole system matched. As far as R-22 vs 410, you should consider the 410. Our costs have risen dramatically on the R22 refrigerant because of the phase out, and they will continue to do so. 410 should be stable for many years to come.
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