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Discussion Starter · #1 ·
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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Are there cold air returns on the top floor?
 

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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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Discussion Starter · #8 ·
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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Discussion Starter · #9 ·
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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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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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.
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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Discussion Starter · #12 ·
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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He forget to screw the pipes together or something?:laughing:
 

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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.
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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Discussion Starter · #16 ·
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.
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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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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Discussion Starter · #18 ·
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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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
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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