A/C question for the pro's on here...

[StevieC]

So Adam called me up yesterday afternoon and told me that the A/C isn't working at his house. (He is still living at his folks house until he finds a job out here).

I told him not to worry that I would pickup my dad and we would come down with our can of R-22, gauges and multi-meter and have a look-see. (It felt like 40C yesterday with the humidity)

So we get there and troubleshoot and we determine the compressor is seized in the outdoor unit. (Compressor makes a whining sound when power is applied gets hot and nothing happens). (Dad has his A/C license and has been mucking around with all sorts of A/C units for over 35 years)

So they call to have a new one installed today.

My question is this... They had a 1.5 Tonne which I believe is a 18,000 BTU and they are getting a 2.0 Tonne (24,000 BTU) unit.

The old unit on really hot/humid days would run pretty much the whole day and maintain and slightly decrease temperature as long as you weren't cooking etc.

So how much better is the 2 tonne going to be over the 1.5 tonne?

Our goal is to extend the life of the compressor unit as this unit that died is only 7 years old. (Carrier)

And the new unit (Carrier) comes with a 10 year warranty which was another reason they went for the 2 tonne instead of the 1.5 the new unit also has a 15.8 SEER rating. (is that good?)

They didn't want a Carrier again but went with them because of the financing option available and the short notice install date (next day) they could have.

The new one also uses 410A instead of R-22.

Your thoughts, opinions etc. are welcome.

Steve

 

[scurvy]

410A is better than R22 as far as availability, but they will need to flush the entire refrigerant loop. IMO hydrocarbon refrigerants (especially R290, aka 'propane') are the way to go for stationary installations, but that's a different story.

2 ton unit will definitely cool the house better if the 1.5 ton could barely keep up. 15.8 SEER rating is good, as is the 10 year warranty. Sounds like the house could probably use a 2.5 ton compressor, though.

 

[StevieC]

They went as big as they could afford. His mom is out of work at the moment and his dad is going to be forced to retire shortly so they wanted to keep expenses down. Plus their 2 vehicles need replacing so you can see why they didn't spend more on the unit.

They are replacing the lines with new piping and the A-Coil as well. They were told it had to be done because of the old gas that was in the previous unit and to comply with Carrier warranty standards. Probably for the best anyways to prevent leaks etc.

When I buy a house for Adam & I, I told him I didn't care if I spent $10K but I was going to put in the biggest/best A/C & furnace I could find because it will last longer and use less energy if it's over-speced (to a point of-course) but it seems here in Canada all the contractors under-spec things to keep the prices cheap and to keep repair work flowing for themselves and I'm sure they get kick back from the Gas/Hydro companies.

 

[J. A. Rizzo]

Is the coil also being changed, or just the condenser/compressor unit?

 

[StevieC]

The unit came with a new A-Coil yes.

 

[StevieC]

Here is what it looks like and some of the features...

Sound

* Sound as low as 74 dBA with accessory sound blanket

Reliability, Quality and Durability

* Scroll Compressor
* Field-installed Filter Drier
* Front-seating Service Valves
* Internal Pressure-Relief Valve
* Internal thermal overload
* Baked-on powder paint
* Dense wire coil guard—Standard

They say that the SEER rating is 13-11 but the pamphlet Adams folks have say 15 so maybe it was changed?

Here is a link: http://www.commercial.carrier.com/commercial/hvac/product_technical_literature/1,3069,CLI1_DIV41_ETI4922_PRD1285_SIT12,00.html

 

[Virtuoso]

13 is the lowest SEER rating they are allowed to manufacture since '06. IIRC

They can sell old stock if they have it, tho.

 

[bepperb]

Stevie, having an oversized furnace/ac unit isn't that great. We had a 56000 btu furnace, replaced it with a ~74000 btu, and it generates a lot more wind noise through the vents since it needs to move more air to keep the output temp differential in range. I guess a variable speed blower would fix this, I dunno. I will say the difference between a 24 year old 90% furnace and a new 96% efficiency furnace is about 20 or 30 bucks a month on our natural gas bill, though, so it will actually pay for itself in a few years.

I thought the way you did, now I've learned for the hundredth time to stop trying to outsmart people who do things every day. 50% oversized was too much.

 

[JonnySaab]

more tonage is not always better. You want the right spec for the load calculations on the house. A unit too large will start and stop all day when a proper fitted unit will run all day. a 2 speed fan is better. Its all about efficency!

 

[440Magnum]

Originally Posted By: StevieC
roubleshoot and we determine the compressor is seized in the outdoor unit. (Compressor makes a whining sound when power is applied gets hot and nothing happens).


I assume you checked out the start cap and potential relay (if present) and tried a hard-start kit if it didn't already have the above?

As far as the 2-ton vs 1.5 ton, you'll only be getting part of the capacity increase unless the indoor (evaporator) coil was replaced also (edit- just saw the later post where you said a new A-coil was installed.) The one risk is that the bigger outdoor unit may freeze up the indoor coil since it has a smaller air-handler than the 2-ton unit "should" have. But really, home systems are pretty forgiving to slight mismatches in indoor/outdoor units.

 

[StevieC]

Originally Posted By: Virtuoso
13 is the lowest SEER rating they are allowed to manufacture since '06. IIRC

They can sell old stock if they have it, tho.
I was just talking to Adam's mom because she had questions about the install and she told me the manual has a Sticker on the front that says 15.8 SEER so they must have updated it since the original specs were put out on the website.

 

[StevieC]

Originally Posted By: bepperb
Stevie, having an oversized furnace/ac unit isn't that great. We had a 56000 btu furnace, replaced it with a ~74000 btu, and it generates a lot more wind noise through the vents since it needs to move more air to keep the output temp differential in range. I guess a variable speed blower would fix this, I dunno. I will say the difference between a 24 year old 90% furnace and a new 96% efficiency furnace is about 20 or 30 bucks a month on our natural gas bill, though, so it will actually pay for itself in a few years.

I thought the way you did, now I've learned for the hundredth time to stop trying to outsmart people who do things every day. 50% oversized was too much.


I don't want to go that big oversize but I also want a unit that doesn't have to run like a fat man on a treadmill who can't catch his breath.

 

[StevieC]

Originally Posted By: JonnySaab
more tonage is not always better. You want the right spec for the load calculations on the house. A unit too large will start and stop all day when a proper fitted unit will run all day. a 2 speed fan is better. Its all about efficency!
apparently this is a 2 stage system ?!?

 

[StevieC]

Originally Posted By: 440Magnum

I assume you checked out the start cap and potential relay (if present) and tried a hard-start kit if it didn't already have the above?


Yes we checked these... No good. Then the thermal overload kicks in and cuts the power and then it tries again with no go.

They said the compressor was noisy for the last couple of weeks leading up to this but thought it was just because it was hot outside. Amazing how the truth comes out after you find the problem.

 

[Bill in Utah]

Originally Posted By: JonnySaab
more tonage is not always better. You want the right spec for the load calculations on the house. A unit too large will start and stop all day when a proper fitted unit will run all day. a 2 speed fan is better. Its all about efficency!


VERY true. MY dad and I built our SAME homes the same time. His has a 5 ton system and I have a 4 ton. Both 13 seer and installed in 1999.

Both are running fine but his home when the AC comes on its a cold rush then the system shuts off 10-15 mins later on a real hot day per hour. Mine runs for 20-25 mins and then shuts off with a more gradual cooldown. His then comes on and repeats the cold rush. If its real hot they have to leave their fan on high speed (2 speed fan in both systems) to keep the cycling down. Even with that their electric bills (and they keep their house warmer than mine) are $40-$60 more every month that the A/C is used.

Reason why he went bigger than the A/C guys recommended? "bigger is better"...

My house stays cooler more consistant since the compressor is running a little longer. Also the lower cost in the beginning and lower cost every month is a nice thing to have. But mostly the over cool then the fan running is not a nice benefit in his house.

He has said that when the system fails he will down size. Problem is the system may last a long time!

Bill

PS: And if I could do it again I'd have smaller units but two zones. One for upstairs and one for the other levels.

 

[StevieC]

Thanks Bill

 

[XS650]

Originally Posted By: Bill in Utah


Reason why he went bigger than the A/C guys recommended? "bigger is better"...



AKA: If more is better, then too much is just right.

 

[StevieC]

Well it's in, I just got off the phone with his Dad and it's working great. Quiet and smaller than the old unit. House dropped from 80C to 72c (where they had it) in about an hour.



Steve

 

[XS650]

Originally Posted By: StevieC
Well it's in, I just got off the phone with his Dad and it's working great. Quiet and smaller than the old unit. House dropped from 80C to 72c (where they had it) in about an hour.



Steve

You Canadians are tough, I couldn't handle that high a temperature.

 

[ddrumman2004]

I couldn't handle them temps either and I love hot weather!