Options and advise on new 5 ton unit

[737mechanic]

My house is 13 years old and I have a Trane 5 ton 12 seer R22 unit with gas furnace. I live in Dallas so it gets hot here in the summer. The liquid line at the compressor rubbed a hole in the line so all refrigerant went bye bye. The unit holds 12.6 pounds of R22 and at bucks a pound that's $ just in refrigerant. I have had two different guys come out and give me their recommendations. Both guys said I should replace the unit with a new r410a unit.

Guy #1 $

Remove Old R-22 Evaporator coil & Condensing unit
Remove Old duct board supply plenum
Install new Rheem RCFHA6021AC Evaporator coil
Install new Rheem RAPM060JEZ 14.5 SEER condensing unit
Install new Insulated sheet metal supply plenum
Install new supply collars with dampers and seal with duct sealer
Flush existing refrigerant lines for re-use with 410A
Install new refrigerant liquid line dryer
Install new 36” x48” concrete slab for condensing unit
Evacuate and recharge system with R 410A to proper temperatures and pressures using superheat and sub-cooling method

Guy #2 $

He can install a Carrier 5 ton 13 seer unit INCLUDING furnace for the above mentioned price.

First Question: If guy #1 installs a 14.5 seer unit but uses my existing furnace will it still be a 14.5 seer unit or will it drop it down lower.

Second Question: Out of both systems which one is rated better and what would you guys recommend.

Third Question: Can I buy my own r410a condenser and air handler and install it myself or is that against the law. If it is lawful for me to do myself where could I get the unit from.

Any help and advise appreciated.


Pricing isn't allowed

[BaldLoonie]

The RAPM-060 is 14.50 SEER with any blower.

At 13 years old in Dallas, you should have some life left in a Trane furnace. So up to your budget whether you want to replace it. With the reliability of today's stuff, you might be better off with the old furnace, sad to say

As for DIY, unless you have the tools and training, not a wise move. Hard enough finding a good contractor to install something right. Most nightmares of jobs are poor installation. Buying off the net usually means no warranty and I'd sure want a warranty with my equipment.

[SBKold]

Another thing worth mentioning is having load calc done to see what size unit you actually need rather than just replacing it with what you have. Which is the biggest unit made for residential homes.

It is very difficult to design the ducts and air filter, grille's, etc...to actually deliver that much cooled air to the home.

You may only need a 3.5-4 ton and notice no difference except lower humidity and electric bill.

After all your old unit can only deliver as much air as can go through the existing ducts.

[motoguy128]

Another thing worth mentioning is having load calc done to see what size unit you actually need rather than just replacing it with what you have. Which is the biggest unit made for residential homes.

It is very difficult to design the ducts and air filter, grille's, etc...to actually deliver that much cooled air to the home.

You may only need a 3.5-4 ton and notice no difference except lower humidity and electric bill.

After all your old unit can only deliver as much air as can go through the existing ducts.

+1. A 5 ton that only get 1600CFM with high static pressure will only deliver maybe 0.5 ton more capacity than a 4 ton pushing 1500CFM on hte same ductwork. The 4 ton would run probably almost 20% more efficient overall.


Someone should do a controlled study on this. Take a ductwork system that's size for 4 ton and run a 3, 4 & 5 ton unit along with single and 2 stage equipment.

[SBKold]

+1. A 5 ton that only get 1600CFM with high static pressure will only deliver maybe 0.5 ton more capacity than a 4 ton pushing 1500CFM on hte same ductwork. The 4 ton would run probably almost 20% more efficient overall.


Someone should do a controlled study on this. Take a ductwork system that's size for 4 ton and run a 3, 4 & 5 ton unit along with single and 2 stage equipment.

That would be a very neat study motoguy.

[motoguy128]

I can do a informal study. I'll be comparing the consumption and cooling performance of the equipment in my home this summer to the equipment the last 2 summers. Not very controlled, but it should give some insights. Going from 7 tons total capacity to 4 tons total (2 systems). Plus, during peak time of use electric ratse, both are limited to 1st stage only, so just 3 tons of total capacity from 8AM-9PM weekdays. Its been near design conditions a couple days now and should almost get there today and all indications is that 3 tons will hold 75F and keep it around 42-48%RH. It was 92F yesterday afternoon and it was cycling to hold 75F, and it took 3 hours, but even lowered it to 74F by 8PM, still on 1st stage. So far so good. I'm using a cheap Ace Hardware thermostat and a pair of relays to utilize the "Utility Curtailment" feature on my Infinity condensers.

Always a little tricky trying to balance energy savings and comfort. Sometimes they can be made to work together if you have good building performance to start.

[tipsrfine]

They have new refrigerant that replaces R-22 that allows you to keep your existing equipment. It is cheap and will be around for a very long time. I believe all you need to do is to replace your liquid line filter dryer and your schrader valves (don't know why this is).

[737mechanic]

They have new refrigerant that replaces R-22 that allows you to keep your existing equipment. It is cheap and will be around for a very long time. I believe all you need to do is to replace your liquid line filter dryer and your schrader valves (don't know why this is).

I have read about some of the alternatives but am very skeptical on whether they would work good. I did find the leak and can fix myself but hate to invest hundreds of dollars in refrigerant only to have the compressor go out next mount.

BaldLoonie

The RAPM-060 is 14.50 SEER with any blower.

At 13 years old in Dallas, you should have some life left in a Trane furnace. So up to your budget whether you want to replace it. With the reliability of today's stuff, you might be better off with the old furnace, sad to say

As for DIY, unless you have the tools and training, not a wise move. Hard enough finding a good contractor to install something right. Most nightmares of jobs are poor installation. Buying off the net usually means no warranty and I'd sure want a warranty with my equipment.

Thank you for the info. If the carrier with new furnace is a 13 seer and the rheem without new furnace is a 14.5 seer and both quotes are within a 100 dollars from each other would I be better off with the rheem or the carrier. I did notice the rhem is their prestige series and I don't know about the carrier.


Thank you all for your comments.

[estherhead]

We have been using the "drop in" replacement for R-22 for some months now. It does require a new filter-drier but we do that for any evacuation and recharge. It costs close to R410a and will probably not go up. If you look up the life expectancy of an AC or heat pump, you are getting close right now and Texas would really work it. My reccomendation would be to clean the system, put a new drier on and recharge with R-22 "drop-in" and plan on replacing the whole system in the next year or two. SEER is based on system performance not just the outdoor unit. A high SEER unit on a 14year old indoor blower unit probably won't be as high as you want.

[737mechanic]

We have been using the "drop in" replacement for R-22 for some months now. It does require a new filter-drier but we do that for any evacuation and recharge. It costs close to R410a and will probably not go up. If you look up the life expectancy of an AC or heat pump, you are getting close right now and Texas would really work it. My reccomendation would be to clean the system, put a new drier on and recharge with R-22 "drop-in" and plan on replacing the whole system in the next year or two. SEER is based on system performance not just the outdoor unit. A high SEER unit on a 14year old indoor blower unit probably won't be as high as you want.

I would love to give that a try first. Can you tell me what drop in you are using with success. I am seeing a few different types and not sure which would be the best. Also does the drop work as a 1 to 1 or do you use less. One drop in I found was said you use 40 percent less than r22. Also does the drop in stuff cool as good or is the system going to be working harder to keep the temp where I want it causing my bill to go even higher.

[udarrell]

Were I you, I'd try the new sub for R-22.

Have the ductwork checked after setting blower to deliver maybe as low as 1725-CFM for the 5-Ton system; though don't run it with too light a load on the indoor coil.
Get a static pressure done that includes the filter & consider making the Return-Air filter area larger, with maybe 2 large return air filter racks.

Make changes in duct system to get it as close to .5" as possible. An Ace swing differential tstat will help...

[tipsrfine]

I've heard that the replacement for R-22 is actually easier on the compressor- less head pressure & heat.

[737mechanic]

The problem with THE replacement is there are tons of different ones out there and I have no idea which replacement you guys keep referring too.

[estherhead]

I would love to give that a try first. Can you tell me what drop in you are using with success. I am seeing a few different types and not sure which would be the best. Also does the drop work as a 1 to 1 or do you use less. One drop in I found was said you use 40 percent less than r22. Also does the drop in stuff cool as good or is the system going to be working harder to keep the temp where I want it causing my bill to go even higher.

I just realized you and I are not supposed to be over here until we are approved. So this will be my last reply in this area until I'm approved. I was going to PM you, but I can't figure out how to Private Message. Anyway, we use Nu-22. We like it. That's all I'm gonna say here until I'm approved. Sorry moderators! I couldn't leave the poor guy hanging when he directly asked me. Off to find out about private messages.....

[Patrick Eubanks]

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