replacement for Lennox 2-stage HS21

[sjanowsky]

My Lennox HS21 two speed 5-ton unit died a couple of months out of warranty.
The inside unit is (I assume) in great shape (Harmony-II 3-zone). What would be a compatible / recommended replacement?

One contractor is recommending a Trane XR14, which I'm leaning against both because I'd prefer a higher efficiency unit and a two-stage.

So...
is installing a single-stage A/C a really bad idea?
can the existing air handler be used with the new R-410A A/C's?

Thanks

[mblanks]

One contractor is recommending a Trane XR14, which I'm leaning against both because I'd prefer a higher efficiency unit and a two-stage.

Ask for a higher efficiency system quote.

So...
is installing a single-stage A/C a really bad idea?

If you've had a two stage system, then installing a single stage system will likely increase your electrical consumption.

can the existing air handler be used with the new R-410A A/C's?

NO!

[RyanHughes]

It's best to replace both the indoor and outdoor units at the same time to ensure efficiency and to avoid future problems down the road. Good luck. You really should be looking into getting matching air handlers.

[beenthere]

Get a quote on a Lennox XC21

[t527ed]

what is model# of existing air handler??

could be a rated match with lennox xc16 or xc21 if not to old, would have to replace the txv.

[badboyheel]

yeah i agree with beenthere get a quote on the xc21.

[classical]

The HS21 is an R-22 unit so the air handler would not be a good match for an R-410A condenser.

Check out the Trane or American Standard 18 SEER two-stage unit they are R-22 and work fine on the CB32 MV AH. I have done this in the past when the HS-21 coils have failed without any problems.

[sjanowsky]

what is model# of existing air handler??

could be a rated match with lennox xc16 or xc21 if not to old, would have to replace the txv.

The air handler is CB31MV-65-1P

[RyanHughes]

That's an ARI-rated match with many condensers from Lennox's current product line (including XC16-060 and XC21-060). You're probably in good shape if they replace the TXV (probably necessary though ARI doesn't show any TXV associated with the air handler in the ratings).

[t527ed]

That's an ARI-rated match with many condensers from Lennox's current product line (including XC16-060 and XC21-060). You're probably in good shape if they replace the TXV (probably necessary though ARI doesn't show any TXV associated with the air handler in the ratings).

there you go, change the txv and have an ari rated match..........

[beenthere]

I thiink his old unit used a TXV.

[classical]

That's an ARI-rated match with many condensers from Lennox's current product line (including XC16-060 and XC21-060). You're probably in good shape if they replace the TXV (probably necessary though ARI doesn't show any TXV associated with the air handler in the ratings).

The two units you are recommending are R-410A and his current system is R-22. I don't believe that coil was rated for R-410A and once used with R-22 it does not need to be used with R-410A.

If you are not a pro don't understand the consequences of your recommendations don't make them. If you are supposed to be a pro and don't understand the consequences then don't make them.

[RyanHughes]

The two units you are recommending are R-410A and his current system is R-22. I don't believe that coil was rated for R-410A and once used with R-22 it does not need to be used with R-410A.

If you are not a pro don't understand the consequences of your recommendations don't make them. If you are supposed to be a pro and don't understand the consequences then don't make them.

Classical,

So ARI just rates systems that don't work together? Look up ARI reference #1003799 and #545745. Look like good matches to me.

t527ed works with Lennox systems, and his response was

there you go, change the txv and have an ari rated match..........

What kind of consequences are you expecting from a system rated by the American Refrigeration Institute? The TXV can be changed, and the system can be cleaned out and vacuumed. I understand the possible repercussions of using a coil that was used with a different type of refrigerant, and that's why a good company should do this. I'm very careful with my responses, by the way, and I certainly do not see any issue with this one. If you have any enlightenment to shed on the matter, I'll gladly listen.

[jjer]

Look at XC16 or XC21 from Lennox. If you use existing air handler make sure contactor flushes properly and uses R410 TXV. Both units are 2-stage

[classical]

Classical,

So ARI just rates systems that don't work together? Look up ARI reference #1003799 and #545745. Look like good matches to me.

t527ed works with Lennox systems, and his response was



What kind of consequences are you expecting from a system rated by the American Refrigeration Institute? The TXV can be changed, and the system can be cleaned out and vacuumed. I understand the possible repercussions of using a coil that was used with a different type of refrigerant, and that's why a good company should do this. I'm very careful with my responses, by the way, and I certainly do not see any issue with this one. If you have any enlightenment to shed on the matter, I'll gladly listen.

It is a very bad idea to use a coil that has been used with R-22 and convert it with R-410A. Every manufacturer strongly recommends against this practice regardless of how good you are. A coil is not a line set, the coil holds oil and cannot be fully flushed out even with RX-11 and an evacuation no matter how thorough will not remove oil.

ARI will list the components as matching but they don't know what generation the unit is or that it has been used with R-22. ARI is not the last word on what to do when it comes to A/C work. In fact what the are is very basic it is information and information is good, but you have to temper that knowledge with experience.

The OP may be able to have a new coil installed in the AH, I am not that current on Lennox but I doubt a current coil will fit the older cabinet.

The AM/Std two compressor two-stage unit is R-22 and works very well with the CB32 MV AH I have done it several times because the HS-21 had a very big problem with condenser coil failures. I have an HS-21 on my house and have had to replace the coil if it fails again I would consider installing this combination.

[RyanHughes]

It is a very bad idea to use a coil that has been used with R-22 and convert it with R-410A. Every manufacturer strongly recommends against this practice regardless of how good you are. A coil is not a line set, the coil holds oil and cannot be fully flushed out even with RX-11 and an evacuation no matter how thorough will not remove oil.

ARI will list the components as matching but they don't know what generation the unit is or that it has been used with R-22. ARI is not the last word on what to do when it comes to A/C work. In fact what the are is very basic it is information and information is good, but you have to temper that knowledge with experience.

The OP may be able to have a new coil installed in the AH, I am not that current on Lennox but I doubt a current coil will fit the older cabinet.

The AM/Std two compressor two-stage unit is R-22 and works very well with the CB32 MV AH I have done it several times because the HS-21 had a very big problem with condenser coil failures. I have an HS-21 on my house and have had to replace the coil if it fails again I would consider installing this combination.

Thanks for sharing the logic behind your statement. I guess I shouldn't have been so quick to suggest one of those models due to the old refrigerant being R-22, but I'm not so sure it wouldn't work. The coil has oil in it, but doesn't the lineset? Are you saying that the oil in the coil cannot be removed unlike the oil in a lineset that is removed by flushing? Would the residual oil left in the coil be significant to cause issues? Wouldn't a good flush and vacuum along with a new TXV be sufficient?

An American Standard/Trane on a Lennox coil, eh? Isn't that against the matching law of HVAC? Just goes to show you that sometimes mismatching works, and sometimes it doesn't. Do the customers not care about the risk of having no warranty and no reassurance of efficiency and capacity as a rated system?

Conflicting viewpoints here--just what the OP wanted.

[t527ed]

The two units you are recommending are R-410A and his current system is R-22. I don't believe that coil was rated for R-410A and once used with R-22 it does not need to be used with R-410A.

If you are not a pro don't understand the consequences of your recommendations don't make them. If you are supposed to be a pro and don't understand the consequences then don't make them.

current A/H is rated for r-410, no reason it could not be flushed out and a new txv installed.

better than mismatching it with a choo choo unit just because they still use r-22...............

[beenthere]

An American Standard/Trane on a Lennox coil, eh? Isn't that against the matching law of HVAC? Just goes to show you that sometimes mismatching works, and sometimes it doesn't. Do the customers not care about the risk of having no warranty and no reassurance of efficiency and capacity as a rated system?

Conflicting viewpoints here--just what the OP wanted.

When he does that. He is taking all responsibility for weather or not it performs.

There use to be a member here that use 3 ton nominal rated evaps with 5 ton condensers.

Special application sort of.

[classical]

When he does that. He is taking all responsibility for weather or not it performs.

There use to be a member here that use 3 ton nominal rated evaps with 5 ton condensers.

Special application sort of.

You are referring to Airman1 (David Debien) I worked for him for 5-years. He was not the only person to do this in fact the original concept was recommended by Lennox. I still occasionally apply nominally rated coils undersized to the condenser. It depends on the application.

In fact my current system in my house is a downsized coil on a two-stage HS-21 condenser the coil is an Aspen.

Installing an R-22 two stage condenser on an existing AH that uses R-22 is certainly a better solution than trying to mix refrigerants.

Ryan an evaporator coil is aeries of horizontal copper tubing with a multitude of "U" tubes; a line set is only partially horizontal and if there are not any or only a few dips a very minimal oil will be retained. I have seen evaporator coils just loaded up with oil especially on systems that have been run low on refrigerant.

Yes it is beneficial to use a matched system but a coil is a coil and the compressor doesn't care who makes the coil. The TEV is going to control the superheat and airflow and charge will control the SC.

[beenthere]

I couldn't remember Davids screen name.
And I didn't want to botch the spelling of his last name. I knew you would know who I was talking about.