# Questions



## Chris Johnson (Apr 19, 2007)

I'm not an HVAC guy, I'm the if it's hot turn on the AC if it's cold turn on the heat.

Project we are looking after, more like inherited is probably a better term.

Townhouses, 3 story plus basement/crawlspace. Roughly 3000 sq ft, all ICF walls, R50 pink in ceiling. Flat roof if that matters.

Cold air return on air handler reads air coming in at 20c, it's being pushed out at 11.5c. We changed the fan in the air handler from 1/3hp as supplied to a 1hp thinking air flow was not enough for a 3000 sq ft unit.

Air coming out at registers is 14c

We have closed the dampers on the lower floors and full flow on top floor.

Bottom floor even when dampers closed is 14c middle floor can't get below 20c, top floor can't get below 24c.

Any ideas?

It's the end unit, long side wall is facing south, basically sun hits the unit all day


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## Chris Johnson (Apr 19, 2007)

Condenser unit is 2 tonne as per heat loss calcs, A coil is 3 tonne


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## Inner10 (Mar 12, 2009)

Are there cold air returns on the top floor?


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## Chris Johnson (Apr 19, 2007)

Yes, 2 on each floor

It's a designed system, engineered and stamped. But you know what that means around here


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## beenthere (Mar 5, 2009)

The 1 HP motor probably won't last long in that unit. Not enough air to keep it cool enough, nd not enough load on it. A 100% efficient 1/3 HP motor would generate 840 BTUs of heat. A 100% efficient 1 HP motor would generate 2,546 BTUs of heat. Obviously no motor is 100% efficient. But the point is, the larger motor is actually, hurting the A/C's ability to cool the house.

Put the 1/3 HP motor back in. Then have the TESP the blower is working against measured, and see if it is close to the manufacturer's rating. If its too much higher, then the duct work is too small and or the air filter too small. 

Next, check the Manual j load calc, and see if the sensible load is within the A/C's sensible ability/capacity. The engineer may have miss calculated its sensible capacity.


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## Chris Johnson (Apr 19, 2007)

TESP?

Manual J?

In laymans terms have another HVAC engineer and HVAC contractor review it?


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## flashheatingand (May 3, 2008)

Could they break down what the cooling load is for the various floors? Two ton system seems awfully small for 3000 ft 2 home even if you t take out the basement in the equation..


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## Chris Johnson (Apr 19, 2007)

I'm okay with the 2 tonne, upto 3500 ft when building with ICF, it's not uncommon for me to see that.

ICF rates at R24, but acts like greater then R38 in our area, has a U value of .0003 literally no air transfer.

I used a cheap temperature laser yesterday on the walls, windows and ceiling

Windows and ceiling were reading 24c, windows were all over, in the shade 18c in direct sunlight 28c.

I'm thinking I need to borrow a doodad to measure CFM at the registers to see what is actually coming out.

It is a high velocity system as well, not sure if that makes any difference.


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## Chris Johnson (Apr 19, 2007)

At the end of the day, this needs to be fixed and working properly, people pay 1m for a townhouse they want it to heat and cool properly.

One area of construction I have never really gained much knowledge is HVAC, so the answers you guys give me is to help me better understand it, have a general idea what is going on and be able talk the talk when needed


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## flashheatingand (May 3, 2008)

Insulation is primarily for heating. Once the house heats up, the insulation keeps the heat. In my experience, it seems as though the tighter houses get quite stuffy when the a/c breaks down. But thats another issue.

Didn't an air balance guy come and check out the cfms and everything? That is what is necessary here. Is the air handler upstairs or in the basement?


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> I'm okay with the 2 tonne, upto 3500 ft when building with ICF, it's not uncommon for me to see that.
> 
> ICF rates at R24, but acts like greater then R38 in our area, has a U value of .0003 literally no air transfer.
> 
> ...


Is it a SDHV system? One of those things that uses 2" ducts with a million tiny vents in every room and a single 12" plenum?


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## Chris Johnson (Apr 19, 2007)

Air handler is in the basement, it doubles as the air handler for the hot water heating system, I'll call it a radiator so to speak.

Not sure if the CFM was checked. Like I said I have inherited this project. The HVAC guy did come back, he was there yesterday and we used his equipment to get all the temperatures I posted.

To be politically correct in saying this, the HVAC contractor is difficult to understand, English is not his first language, communication is difficult...hiring for the lowest price has it's challenges.

So I can't say if the system was balanced. I was the structural contractor for the project so I know how the duct work was done, different then any other high velocity system I've seen before. 

Basically it is an 8x8 duct off the handler for 12-15' then converts to 6" round, for the top floor it runs up 30' to another plenum I'll call it in the attic, that plenum is about 25' of 8x8 again and then 4" flex from there to the diffusers in the ceiling. All items in the ceiling were spray foamed

Main floor everything is branched off the 6" round as it snakes through ceiling between the lower and middle floor, lower floor is the same.

There are 2 return airs per floor

There is an HRV hooked to the HVAC, I think you call it a simple system when installed that way. And then typical Panasonic bathroom fans in each bathroom, 4 total, range hood and 2 gas fireplaces.


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## Inner10 (Mar 12, 2009)

He forget to screw the pipes together or something?:laughing:


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## Chris Johnson (Apr 19, 2007)

Inner10 said:


> He forget to screw the pipes together or something?:laughing:


Ha

No everything was tape on round pipes and mastic on square


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## beenthere (Mar 5, 2009)

Chris Johnson said:


> Air handler is in the basement, it doubles as the air handler for the hot water heating system, I'll call it a radiator so to speak.
> 
> Not sure if the CFM was checked. Like I said I have inherited this project. The HVAC guy did come back, he was there yesterday and we used his equipment to get all the temperatures I posted.
> 
> ...


4" flex? Are you calling it 4" due to the outside dimension, or is it really 4" inside dimension. 

A high velocity air handler often decreases the capacity of the condenser. So the 2 ton condenser may only be able to do 1.6 to 1.8 tons of cooling.

Any chance of being able to post pics of the outlets.

What size return is upstairs.


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## Chris Johnson (Apr 19, 2007)

beenthere said:


> 4" flex? Are you calling it 4" due to the outside dimension, or is it really 4" inside dimension.
> 
> A high velocity air handler often decreases the capacity of the condenser. So the 2 ton condenser may only be able to do 1.6 to 1.8 tons of cooling.
> 
> ...


I call it 4" flex, it's flexible piping, about 1/8" material so not sure if it's inside or out

I'll be back on site tomorrow and can post pics. I think 2nd floor returns are 8x10 grills, using stud cavities


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> I call it 4" flex, it's flexible piping, about 1/8" material so not sure if it's inside or out
> 
> I'll be back on site tomorrow and can post pics. I think 2nd floor returns are 8x10 grills, using stud cavities


Chris it's probably 2" insulated flexible duct.


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## Chris Johnson (Apr 19, 2007)

No it's actually 4", trust me on this one

That's why I said it's not a system I've seen done before, I'm use to seeing the 2"

This whole thing is Greek to me

It's like the HRV, it's a new house, wide open, should have had HRV in each wet zone, not a simple system. I question whether all this BCIN crap has done as any good or not. We can not change anything or it's an automatic fail...even if we are improving the design


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## beenthere (Mar 5, 2009)

If its actual 4" flex duct. The A/C will probably never work right.


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> No it's actually 4", trust me on this one
> 
> That's why I said it's not a system I've seen done before, I'm use to seeing the 2"
> 
> ...


You're ****ting me, you sure as sugar cowboy? They took 4 inch flexible duct then buried it in spray foam?


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## flashheatingand (May 3, 2008)

How hot does it get there? I can't imagine turning up the AC when its 85. Is it a humidity thing?


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## flashheatingand (May 3, 2008)

Wouldn't be surprised if you have an issue with the refrigerant charge our something. Going to have a doto some research on this aspiration cooling.


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## Chris Johnson (Apr 19, 2007)

Yes, the expression here is...it's not the heat, it's the humidity

It doesn't get hot, it gets humid and muggy like you wouldn't believe.


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## Inner10 (Mar 12, 2009)

flashheatingand said:


> How hot does it get there? I can't imagine turning up the AC when its 85. Is it a humidity thing?


Humidity here is high, really high. Could be 68 degrees and you will sweat your nuts off from the humidity.

The average accross June/July/August is probably 80 but we will get heat spells that will hit 95.

Despite the vast distance, our summers can be pretty similar to Austin TX. :laughing:


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> Yes, the expression here is...it's not the heat, it's the humidity
> 
> It doesn't get hot, it gets humid and muggy like you wouldn't believe.


It can also get fvcking hot!

Here's Toronto 2013:


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## Inner10 (Mar 12, 2009)

Then if you like your weather a little more erratic you move to Ottawa:


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## flashheatingand (May 3, 2008)

latent cooling load? Capacity of the equipment with latent cooling? B.T. is on top of this stuff (as well as a lot of other stuff). Around here we don't have a high latent load.

Still, I would expect at mid eighties, the indoor temp should easily be able to bring the house down without running all day.


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## Inner10 (Mar 12, 2009)

flashheatingand said:


> latent cooling load? Capacity of the equipment with latent cooling? B.T. is on top of this stuff (as well as a lot of other stuff). Around here we don't have a high latent load.
> 
> Still, I would expect at mid eighties, the indoor temp should easily be able to bring the house down without running all day.


It must be that worthless ICF stuff causing all the problems. :laughing:


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## Chris Johnson (Apr 19, 2007)

Inner10 said:


> It must be that worthless ICF stuff causing all the problems. :laughing:


That usually is the problem, it so simple it complicates everything else. 

I love the people wanting to build ICF and add Geo-Thermo...ummm you will never see a return on your investment in our lifetime


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## beenthere (Mar 5, 2009)

I'm waiting for the brand and model number of the air handler. Something don't look right about it, for it to be a high velocity unit. But it could just be the angle of the pic.

HV systems usually have a very god shr(Sensible Heat Ratio). They usually dehumidify real well. But suffer some in lowering temp.


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## Chris Johnson (Apr 19, 2007)

Today's a holiday here in Canada so I plan to go tomorrow...provided they get the bridge fixed...you may have heard the news, a drunk dump truck driver drove over a trestle type bridge with his box up, needless to say it wasn't a good ending, no one died but that bridge is the main artery from western New York into Canada....traffic is bunged up pretty good for a long weekend...and this project of mine is right below the bridge


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## beenthere (Mar 5, 2009)

Hate when crap like that happens.


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## Chris Johnson (Apr 19, 2007)

You should google it, it's a big event for us Canadians it's called the Burlington Skyway...and possible structural damage from this dump truck slamming into the overhead girders at at least 55mph


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## Inner10 (Mar 12, 2009)

beenthere said:


> I'm waiting for the brand and model number of the air handler. Something don't look right about it, for it to be a high velocity unit. But it could just be the angle of the pic.
> 
> HV systems usually have a very god shr(Sensible Heat Ratio). They usually dehumidify real well. But suffer some in lowering temp.


I can't tell from the pic but I will bet a coffee that it's a UNICO 2430

http://www.unicosystem.com/the-system/how-it-works/air-handlers/

Very popular unit in new homes here.


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> You should google it, it's a big event for us Canadians it's called the Burlington Skyway...and possible structural damage from this dump truck slamming into the overhead girders at at least 55mph


I saw a pic, looks pretty bad. Enjoy traffic.


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## beenthere (Mar 5, 2009)

Inner10 said:


> I can't tell from the pic but I will bet a coffee that it's a UNICO 2430
> 
> http://www.unicosystem.com/the-system/how-it-works/air-handlers/
> 
> Very popular unit in new homes here.


I hope it is. But the 1/3 HP blower motor make me think it may not be.


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## Inner10 (Mar 12, 2009)

Chris, this exact second I'm working in a 2800 square foot 3 story ICF house. System is a high velocity, 3/4 horse motor and 3 ton A.C.


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## Chris Johnson (Apr 19, 2007)

So what are you telling me?

Working properly? What's the setup? Zoning?


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## beenthere (Mar 5, 2009)

Did you get the brand and model number yet.


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## Inner10 (Mar 12, 2009)

Chris Johnson said:


> So what are you telling me?
> 
> Working properly? What's the setup? Zoning?


Only one zone, works well, but there arn't any window coverings and the thermal loading is intense on a sunny day. The system keeps up but you can definitely feel a difference between the front and back of the house when the sun is shining directly in.


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