Home hvac

[clrussell]

I remember you guys all talking about diy mini splits a while back. It got me thinking.

Is home hvac replacement something I can do myself?

Ive moved an hour from the house I own and have rented it out for the last two years. The current renter has moved out and I’m going to put it on the market to sell.

House is roughly 1500 sq

The Heat pump compressor is shot (I’m told). With a replacement cost of roughly $2,000.
The unit is a 2005 model year. 2.5 ton 10k electric backup.
Full unit replacement and stepping up to a 15k electric backup was quoted at $9,000 installed

Looking online I can get a 3 ton 10k unit with air handler for roughly $3,000.

Or go to a central ducted split style for the same money.

Obviously refrigerant will add to the cost, as well as lines/ wiring to install.


I’m hvac certified across the board, however have never messed with home stuff. And it’s been 11 years since I took that test.

Here are the two products I’m looking at. Goodman is what I have now at the house.

Pioneer 36,000 BTU 3 Ton 18 SEER Ducted Central Split Air Conditioner Heat Pump System DYR3036GMFI18R - The Home Depot

Ducted central split units offer climate control for multiple rooms and areas, utilizing a network of air ducts (existing or field designed) using a single set of equipment. Ideal for whole-house climate

www.homedepot.com

Goodman GSZ1436ARUF - 3.0 Ton Cooling - 36k BTU/Hr Heating - Heat Pump + Air Handler System - 14.0 SEER - 8.2 HSPF

The Goodman - 3.0 Ton Cooling - 36k BTU/Hr Heating - Heat Pump + Air Handler System - 14.0 SEER - 8.2 HSPF GSZ1436ARUF has been discontinued. Check out Expert's recommended alternatives for another top central air package.

www.acwholesalers.com

 

[2004LB7]

it most certainly is doable yourself. most that venture down this path will do the install themselves and call out a tech or buddy who has the license to get the refrigerant and has the vacuum pump and other tools needed. since you already have the certification this should be easy for you

if you already have ducting you may as well stick with it. double check on the new Goodman unit if the lineset is the same size as your old unit. some of the newer R410a systems may use a different size liquid or return line. if you already have the vacuum pump, scale and manifold then you should have no problem doing it yourself. the hardest part will likely be replacing the indoor evaporator

if you are really concerned about utility cost, don't already have ducting or are trying to add new zones then the mini split is probably the best route

if it was my choice I'd just replace the compressor myself. if you have the tools then the cost difference should take a long time to pay off with the savings in electrical

 

[clrussell]

it most certainly is doable yourself. most that venture down this path will do the install themselves and call out a tech or buddy who has the license to get the refrigerant and has the vacuum pump and other tools needed. since you already have the certification this should be easy for you

if you already have ducting you may as well stick with it. double check on the new Goodman unit if the lineset is the same size as your old unit. some of the newer R410a systems may use a different size liquid or return line. if you already have the vacuum pump, scale and manifold then you should have no problem doing it yourself. the hardest part will likely be replacing the indoor evaporator

if you are really concerned about utility cost, don't already have ducting or are trying to add new zones then the mini split is probably the best route

if it was my choice I'd just replace the compressor myself. if you have the tools then the cost difference should take a long time to pay off with the savings in electrical

I have two uncles who can charge the system for me. I don’t have a home manifold set.

The biggest issue I have with replacing the compressor is the entire unit is 15 years old. That seems “old” in terms of hvac to me anyway. I also have no idea lol.

Also the old unit is r22 which is being phased out if I’m researching correctly. Which makes it
Expensive/ hard to Source.

I’m all for repairing it as it’s the less out of pocket for me. (Compressor is a few hundred If I diy that.)

The tech said the compressor is “shorted to ground” which could be as simple as a wiring issue I assume and doesn’t definitively mean the compressor is shit.

I plan to look at that myself before I spent thousands and replace it over a cheap fix.

 

[2004LB7]

I would still look into replacing the compressor. as long as the unit is not abused and the coils are dinged up and the fins bent, dirt packed in them then the only other major parts that are wear items are the condenser fan and blower which are easy enough to change out if/when they go.

you will need to test the oil for acid to see if the compressor contaminated the system. I've delt with plenty of compressors that shorted out. most will short out internally to the frame and pop the fuse or breaker. it's not normal to call out a shorted compressor when its external wiring. unless the HVAC guy is a hack and trying to get you to pay up for an easy fix. but that is easy enough for you to check. just pop the cover off the electrical cover on the compressor, pull the terminals and test the resistance to ground

R22 was phased out in 2010 if I'm not mistaken but there are plenty of drop in replacements available. Nu22 comes to mind. you can also check craigslist and Facebook marketplace for people selling bottles of it. I've seen full ones for between $200-400 around here which is half of retail

the new units run on R410a which is a blend of refrigerants to get the pressure curve needed. the problems with this is that any leaks can't be topped off unless you catch it early but normally you don't know when it leaked until it starts icing up and then it too late. then you have to recover the remaining and put a fresh charge in it. what happens is the blend becomes unbalanced and you can't fix it by putting more in. and because it runs at around double the pressure it can be harder on components so they have to be built with thicker material, stronger compressor walls, etc. the coils are also larger to make up for the lower ability to transfer heat. then there is talks of replacing R410a with another refrigerant soon but this seems to be delayed because the manufacturing cried out for having spent millions retrofitting their plants only to have it change on them again. Plus the techs that had to purchase new equipment to work on them would have to start over with new equipment so they delayed it.

so it you can fix your unit you may be able to wait out the R410a until the replacement becomes mainstream. supposed to be lower pressure and not as sensitive as the current stuff is. hopefully it's not a blend either. crossing my fingers they approve R290 for larger systems

 

[clrussell]

Thank you. Very good info here.

I plan to pull the cover off and see what’s up with the compressor. Will update later this evening.

 

[Chevy1925]

sepcially since you are getting ready to sell it, id just fix/change the compressor and roll on. i dont see dropping 5-10k really changing the house price for ya. hell, we sold our old house with a 35 year unit on it, never batted an eye at it.

 

[clrussell]

Some info.

Looks like shit compressor.

Hook everything up (was unhooked), kick the breaker on it’s starts and runs about 5 seconds then kicks the breaker.

Unhooked the red wire (looks like the main coil in the motor) breaker doesn’t trip when reset.

Here’s a breakdown of the readings I got, checking the winding prong to compressor body.

Also manufactures specs.

 

[2004LB7]

time for new compressor.

if you can swing it, install a suction line filter dryer to protect the new compressor. a liquid line sight glass with moisture indicator. recover all the R22 and reuse it in the system. this should keep you from having to purchase much refrigerant to top the system off.

call up your parts supplier and give them your model of compressor and they can give you a compatible replacement. no need to go with the same manufacturer or high end one. BTUs at the required temps, refrigerant compatibility and voltage are your main requirements and port location second. you should also replace the contactor and if needed because it's either a different rating (or failing) the capacitor too

pick up a acid test kit to see if you need to add any neutralizer

 

[clrussell]

time for new compressor.

if you can swing it, install a suction line filter dryer to protect the new compressor. a liquid line sight glass with moisture indicator. recover all the R22 and reuse it in the system. this should keep you from having to purchase much refrigerant to top the system off.

call up your parts supplier and give them your model of compressor and they can give you a compatible replacement. no need to go with the same manufacturer or high end one. BTUs at the required temps, refrigerant compatibility and voltage are your main requirements and port location second. you should also replace the contactor and if needed because it's either a different rating (or failing) the capacitor too

pick up a acid test kit to see if you need to add any neutralizer

Talking to the renter (I thought they had worked on the ac and they had). It originally had a hole in a line due to a wire rubbing it. Which I can see the repair and on the line and the wire.

They had the line fixed and charged it back up. Which then they found out the compressor wasn’t working.

But they bought a bottle of refrigerant, and it’s still at the house. It feels like a 3/4 bottle. And is 427A which according to the ole inter web is a drop in replacement.

I’m going to see if I can find a parts supplier for the compressor. Google search isn’t much help so far.

Then it’s just recover, acid test. Replace parts recharge. In theory.

 

[2004LB7]

R427a is not a direct drop in replacement since it's not compatible with mineral oil used in R22 systems. you will need to change out the oil to POE and flush the lines and coils. easy enough to do if you are removing the compressor. makes me wonder if that was the reason for the compressor failure if the oil wasn't changed over.

 

[clrussell]

R427a is not a direct drop in replacement since it's not compatible with mineral oil used in R22 systems. you will need to change out the oil to POE and flush the lines and coils. easy enough to do if you are removing the compressor. makes me wonder if that was the reason for the compressor failure if the oil wasn't changed over.

Very possibly the issue.

I’ll add flushing to the procedure. I’ve got a call in to a couple local places for a compressor. If I don’t get a call back I’ve found some online.

 

[2004LB7]

luckily you won't need to be too concerned with acid in the oil if you flush it all out and start over

 

[clrussell]

Compressor will be here tomorrow. I’ll keep an update.

 

[2004LB7]

make sure to get ahold of some nitrogen, not only to help flush the lines but to purge the air when brazing the compressor in.

also, don't forget the filter dryer

 

[2004LB7]

Compressor will be here tomorrow. I’ll keep an update.

what type of oil does the compressor come with? POE or mineral oil?

 

[clrussell]

R427a is not a direct drop in replacement since it's not compatible with mineral oil used in R22 systems. you will need to change out the oil to POE and flush the lines and coils. easy enough to do if you are removing the compressor. makes me wonder if that was the reason for the compressor failure if the oil wasn't changed over.

Dumb question. Are there different weights of poe oil?

 

[clrussell]

make sure to get ahold of some nitrogen, not only to help flush the lines but to purge the air when brazing the compressor in.

also, don't forget the filter dryer

I think I’m just going to pay an hvac guy cash to install on the side

what type of oil does the compressor come with? POE or mineral oil?

Honestly didn’t even think to ask. But I did make sure I got a contactor and capacitor with it

 

[2004LB7]

Dumb question. Are there different weights of poe oil?

I've never heard of different weight POE oils. there may be but for HVAC use I've never seen any

 

[2004LB7]

I think I’m just going to pay an hvac guy cash to install on the side

Honestly didn’t even think to ask. But I did make sure I got a contactor and capacitor with it

if it's mineral oil, you will have to dump it out and measure in the right amount of POE. your HVAC guy should know what to do

 

[clrussell]

I've never heard of different weight POE oils. there may be but for HVAC use I've never seen any

Perfect thank you!