Fresh air intake

[Wanderer]

Hmm, I don’t know about this guy you have working on your stuff.  Did he install it?

 

You never really want to block your returns.  The furnace has to breathe.  If you want to channel your heat to any particular area more than another, adjust your supplies.  
 

Your furnace might be short cycling due to not being able to prove air flow if it’s starving for combustion air.  Open all your vents and see how it runs.  If it doesn’t short cycle anymore that’s a win.  Then adjust your supply vents to balance your heat.  If this unit was installed correctly, you shouldn’t need to be adding anything.  
 

The furnace shouldn’t cut out via the area around it getting too warm, it takes its call to run from the T stat.  Internally a high limit could trip but that sensor is in the heat exchanger to prevent over firing.  
 

What I described is basic operation.  Systems vary and sometimes have unique features built in but you always have to have the basics in order to run.  Air flow is key and often causes hard to diagnose problems.  Check everything including your furnace exhaust for restriction.  I thought I read it was 95% efficiency rating?  I see in the pic you have only 1 pvc stack.  I’m assuming that’s exhaust going outside the cabin.  High efficiency furnaces should have another stack coming out of the other hole in the cabinet and running parallel to the exhaust to the exterior for outside fresh air intake.  You should have a mix of both outside and inside return air.

 

I’m only a HVAC guy in the sense that I have I have an AAS degree in HVAC and turned a wrench for awhile.  Now I just supervise and point at things and ask questions. 

[delcecchi]

Sounds like wanderer is one of the few  of us who actually knows this stuff.  

 

And going back and looking at the picture, where IS the combustion air coming from?  Seems like it needs to come from outside, either through an intake or by infiltration like in the old days.  New construction is pretty tight, tyvek, good windows, etc so you probably need that fresh air intake. Plus running it to the furnace will save energy sunce you won't be heating the combustion air.  

 

I am beginning to wonder about the installer. 

 

 

[CigarGuy]

Thank you Wanderer for your input! He is the owner/installer of the HVAC company in town. Like I mentioned before, he had me close off all the cold air returns and now the furnace only gets it fresh supply air from laundry room- he told me to leave the door open or install a louvered door for increased air flow. So opening up that one cold air return next to the laundry room isn't going to make that much difference, it's not connected to anything, just an open end that will let some fresh air in from the crawl space. He is going to put a new fresh air stack from the furnace out to the crawl space, not outside. The crawl space never gets colder than 45 degrees in the winter. So, this should have been done during the original install. I'm not buying his theory on short cycling. I just wish he would have installed it with the cold air returns all hooked up like the original install, but I trusted his recommendation. It runs like 7 times per hour, with a short cycle or 3 mixed in.... Can't be right in my opinion! I just can't believe American Standard doesn't have a tech support line to call. Do they have independent HVAC inspectors? Thank you again!

[leech~~]

1 hour ago, delcecchi said:

Sounds like wanderer is one of the few  of us who actually knows this stuff.  

 

 

What am I chopped liver here?  I think I pretty much covered the air flow and pressure issues above! 

Agreed, the installed didn't layout the needs of the dwelling very well! 

[Wanderer]

15 minutes ago, leech~~ said:

 

What am I chopped liver here?  I think I pretty much covered the air flow and pressure issues above! 

Agreed, the installed didn't layout the needs of the dwelling very well! 

No, you’re more like pate   

 

You had it down pretty well.  

[Wanderer]

@CigarGuy,

 

I don’t want to trash the man’s work; I’m not there and can’t look at the entire layout.  But in my opinion if the furnace is in the same location as the old one, all the ducting should’ve been reconnected.  
 

If the new “fresh air” intake is pulling from your crawl space, the crawl space is going to need air from some place.  That could mean pulling from the outside through any leaks you might have, causing it to get below freezing in there.

 

I’ll stick to my guns with, if it’s HE, it needs a pvc intake run to the outside of the house.  It’s the only unlimited source of fresh air you can get.  The returns are to bring inside air back to the furnace, through the filter (your dust control) and mix with the outside air to be heated and redistributed back into the house through the supply vents.  80% efficiency furnaces don’t have fresh air intakes.

 

Makes me wonder what your guys sheet metal resources are.  Seems like he’s avoiding duct work and running an outside air intake for some reason.  I get leery about calling out people who do this work for a living but I admit I’m suspicious.

[CigarGuy]

3 hours ago, Wanderer said:

@CigarGuy,

 

I don’t want to trash the man’s work; I’m not there and can’t look at the entire layout.  But in my opinion if the furnace is in the same location as the old one, all the ducting should’ve been reconnected.  
 

If the new “fresh air” intake is pulling from your crawl space, the crawl space is going to need air from some place.  That could mean pulling from the outside through any leaks you might have, causing it to get below freezing in there.

 

I’ll stick to my guns with, if it’s HE, it needs a pvc intake run to the outside of the house.  It’s the only unlimited source of fresh air you can get.  The returns are to bring inside air back to the furnace, through the filter (your dust control) and mix with the outside air to be heated and redistributed back into the house through the supply vents.  80% efficiency furnaces don’t have fresh air intakes.

 

Makes me wonder what your guys sheet metal resources are.  Seems like he’s avoiding duct work and running an outside air intake for some reason.  I get leery about calling out people who do this work for a living but I admit I’m suspicious.

The old furnace was an upflow installed in crawl space. The new furnace is down flow and installed in the laundry room on the main floor. None of the  cold air return vents in the crawl space are hooked up and had me fill the cold air returns vents on the main level with spray foam. So, the only fresh air getting to the furnace is being drawn in from the laundry room with the door left open to get additional air from the other rooms. Should he run that fresh air pipe from the furnace to outside the house instead of down into the crawl space? He keeps saying there's enough air being drawn in from the laundry room and the other rooms- through the open laundry room door. I say B.S.  If my memory serves me right, I originally had 6 or 7 cold air returns and the same amount of supply vents. I've been looking at YouTube videos and am really getting suspicious of his installation. One other thing I didn't pay much attention to was that he noticed the furnace was flashing an error code, 4 flashes, which is a heat limit something or other code, which I now believe why it short cycling. Do you know a technical support person from American Standard? I think my guy mentioned his name was Jack, didn't get last name! I can't thank you enough for your help!!!

[leech~~]

1 hour ago, CigarGuy said:

 None of the  cold air return vents in the crawl space are hooked up and had me fill the cold air returns vents on the main level with spray foam.

 

This, is a big issue.  But, I'll wait for Wanderer to say why!  

[Wanderer]

2 hours ago, leech~~ said:

 

This, is a big issue.  But, I'll wait for Wanderer to say why!  

Go ahead and ‘splain!  I’m a little groggy here after hunting, dinner and beers...

[leech~~]

20 minutes ago, Wanderer said:

Go ahead and ‘splain!  I’m a little groggy here after hunting, dinner and beers...

 

I'll use words from a HVAC site so my word wouldn't be in question but it's pretty much what I have been saying.  It's all about Hot air in cold air out.

 

"What is the job of cold air returns?

 

Similar to the human body, your HVAC system “inhales” and “exhales” the air around your home. In order for your furnace to run efficiently and your home to heat evenly, this airflow must be in balance. In other words, the amount of air that your furnace “breathes in” must equal the amount of air it “breathes out.”

Cold air returns are what allow your furnace to “inhale” your home’s air. These registers are typically located low to the ground in different areas around your home in order to capture the cold air that sinks to the floor. When warm air is delivered to a room, the existing cold air in that room is pushed into the cold air returns. Once inside your cold air returns, that air travels through your ductwork back to your furnace where it is filtered, heated and sent back to warm your home.

How can you maximize the performance of your cold air returns?

Don’t block your cold air returns. In order to allow for proper air flow, the space around your cold air returns needs to be clear. If you have furniture, TV’s or other household items blocking your registers, it can prevent your cold air returns from doing their job.

Add more returns if needed. Unfortunately, many homes were designed without the proper amount of air returns. Some common symptoms of this include stuffy rooms, uneven heating, high energy bills and unbalanced pressure.

[delcecchi]

And combustion air is in addition to the circulation of heated air especially for a very high efficiency furnace.

[delcecchi]

6 hours ago, CigarGuy said:

The old furnace was an upflow installed in crawl space. The new furnace is down flow and installed in the laundry room on the main floor. None of the  cold air return vents in the crawl space are hooked up and had me fill the cold air returns vents on the main level with spray foam. So, the only fresh air getting to the furnace is being drawn in from the laundry room with the door left open to get additional air from the other rooms. Should he run that fresh air pipe from the furnace to outside the house instead of down into the crawl space? He keeps saying there's enough air being drawn in from the laundry room and the other rooms- through the open laundry room door. I say B.S.  If my memory serves me right, I originally had 6 or 7 cold air returns and the same amount of supply vents. I've been looking at YouTube videos and am really getting suspicious of his installation. One other thing I didn't pay much attention to was that he noticed the furnace was flashing an error code, 4 flashes, which is a heat limit something or other code, which I now believe why it short cycling. Do you know a technical support person from American Standard? I think my guy mentioned his name was Jack, didn't get last name! I can't thank you enough for your help!!!

&so the cold air returns from the living space go to the crawl space, and are now plugged?  

[CigarGuy]

15 minutes ago, delcecchi said:

&so the cold air returns from the living space go to the crawl space, and are now plugged?  

They were disconnected from the old furnace in the crawl space and I plugged them up by the floor registers.

[delcecchi]

7 hours ago, CigarGuy said:

They were disconnected from the old furnace in the crawl space and I plugged them up by the floor registers.

So, if I understand the situation, warm air goes through ducts to various places in the house, but then just moves through the rooms to get back to the furnace to circulate.  The cold air to the heat exchanger, plenum in the furnace as well as the combustion air comes from inside the furnace room?  

And the air for combustion that goes out the (power?) flue comes into the house via infiltration?

[Wanderer]

15 hours ago, CigarGuy said:

The old furnace was an upflow installed in crawl space. The new furnace is down flow and installed in the laundry room on the main floor. None of the  cold air return vents in the crawl space are hooked up and had me fill the cold air returns vents on the main level with spray foam. So, the only fresh air getting to the furnace is being drawn in from the laundry room with the door left open to get additional air from the other rooms. Should he run that fresh air pipe from the furnace to outside the house instead of down into the crawl space? He keeps saying there's enough air being drawn in from the laundry room and the other rooms- through the open laundry room door. I say B.S.  If my memory serves me right, I originally had 6 or 7 cold air returns and the same amount of supply vents. I've been looking at YouTube videos and am really getting suspicious of his installation. One other thing I didn't pay much attention to was that he noticed the furnace was flashing an error code, 4 flashes, which is a heat limit something or other code, which I now believe why it short cycling. Do you know a technical support person from American Standard? I think my guy mentioned his name was Jack, didn't get last name! I can't thank you enough for your help!!!

Sorry, no I don’t know any tech support people from American Standard.  If you have any warranty papers or better yet, the installation manual for your furnace, a number should be in there.  Your contractor should be able to provide  one to you if he didn’t leave one already.  
 

HVAC manufacturer’s have made it more difficult for Joe Homeowner to contact them for DIY fail reasons and to protect their installing contractors.  But even the manufacturers can get it wrong.  I set up the geothermal system in my house and things weren’t operating like they should.  I called tech support for manufacturers of two different parts of my system and walked through the instructions only to find out they printed key information incorrectly.  “Yeah, it’ll never work right the way it’s shown” was a comment I’ll never forget.
 

The fact that your installer says you need to keep the laundry door open to provide enough air is all you need to to know that the installation isn’t correct.  I don’t work with residential equipment, except my own, but even in commercial buildings the systems are balanced to operate with doors closed unless otherwise designed differently.  Whether you made the decision or he made the recommendation to switch locations of the furnace I don’t know.  But there should’ve been ductwork added to keep your DUCTED connection from your rooms to your new furnace.  Pulling from the crawl space does no good if all the returns to it were sealed.  Where will the crawl space get it’s air from?  Sure, with enough alternative methods the end result can probably be completed but it’ll never be right IMO.

Certain things have to be in certain places to satisfy the basic requirements of air flow, or in my case water flow.  Concentrate on getting the basics right then go from there.

[CigarGuy]

2 hours ago, delcecchi said:

So, if I understand the situation, warm air goes through ducts to various places in the house, but then just moves through the rooms to get back to the furnace to circulate.  The cold air to the heat exchanger, plenum in the furnace as well as the combustion air comes from inside the furnace room?  

And the air for combustion that goes out the (power?) flue comes into the house via infiltration?

Del, I think you have most of it right. He never ran a fresh air pipe to the outside of the house, as mentioned by Wanderer. There is no return plenum on the new furnace, so no return duct work running to the furnace. It's all there in the crawl space, just didn't hook it up. All the supply air is going into the furnace through the filter on the side of the furnace as shown in the picture.

[CigarGuy]

1 hour ago, Wanderer said:

Sorry, no I don’t know any tech support people from American Standard.  If you have any warranty papers or better yet, the installation manual for your furnace, a number should be in there.  Your contractor should be able to provide  one to you if he didn’t leave one already.  
 

HVAC manufacturer’s have made it more difficult for Joe Homeowner to contact them for DIY fail reasons and to protect their installing contractors.  But even the manufacturers can get it wrong.  I set up the geothermal system in my house and things weren’t operating like they should.  I called tech support for manufacturers of two different parts of my system and walked through the instructions only to find out they printed key information incorrectly.  “Yeah, it’ll never work right the way it’s shown” was a comment I’ll never forget.
 

The fact that your installer says you need to keep the laundry door open to provide enough air is all you need to to know that the installation isn’t correct.  I don’t work with residential equipment, except my own, but even in commercial buildings the systems are balanced to operate with doors closed unless otherwise designed differently.  Whether you made the decision or he made the recommendation to switch locations of the furnace I don’t know.  But there should’ve been ductwork added to keep your DUCTED connection from your rooms to your new furnace.  Pulling from the crawl space does no good if all the returns to it were sealed.  Where will the crawl space get it’s air from?  Sure, with enough alternative methods the end result can probably be completed but it’ll never be right IMO.

Certain things have to be in certain places to satisfy the basic requirements of air flow, or in my case water flow.  Concentrate on getting the basics right then go from there.

I had him move the furnace to the laundry room, the crawl space is damp and had some rusting issues with the furnace,  plus it was a hassle changing the filter. He'll have to cut through the floor again to install a return plenum, will the ductwork be large enough to supply the proper amount of air back to the furnace?

[delcecchi]

9 minutes ago, CigarGuy said:

Del, I think you have most of it right. He never ran a fresh air pipe to the outside of the house, as mentioned by Wanderer. There is no return plenum on the new furnace, so no return duct work running to the furnace. It's all there in the crawl space, just didn't hook it up. All the supply air is going into the furnace through the filter on the side of the furnace as shown in the picture.

I'm not a hvac guy by a long shot, but that just seems wrong.  Close a door and the room gets cold because no place for the air to go?  

[CigarGuy]

1 hour ago, delcecchi said:

I'm not a hvac guy by a long shot, but that just seems wrong.  Close a door and the room gets cold because no place for the air to go? 

If the door is closed, not enough return air getting to the furnace.

[leech~~]

On 12/20/2019 at 10:09 PM, CigarGuy said:

The HVAC guy came out and checked it out again. He suggested opening up one of the cold air returns that I sealed off and he's going to come back and run another return off the furnace down into the crawl space to supply more fresh air. Also, wants me to buy a new thermostat. Because it's a down flow furnace, the hot air wants to rise up towards the furnace, he thinks that might cause it set off a sensor, causing it to cycle more often, he's going to check that thought out with a tech guy and get back to me.

 

Any up dates on this yet? 

[CigarGuy]

As noted by you-all, I have some serious issues. If you're interested, look at the website, HVAC-talk, under residential installation, heading "down flow installation" by Billy's, page 2. Got some more great info from the pros.

[leech~~]

Holy craap. The very first guy made a big point!  I would print out this whole thread so you have this info available if you go to the County like the one guy suggested and I will as well.  You could be just circulating carbon monoxide throughout the place! 

 

"It is illegal - everywhere so far as I know - and with excellent good reason - that domestic air return cannot come from the same place that the combustion air to the furnace burners comes from.

Any interesting thing to know, and it is easy and safe for you to get, is the temperature of the room air temperature, the temperature of the return air actually going into the furnace, and the supply air temperature coming out the closest register to the furnace."

PHM

Edited January 5, 2020 by leech~~

[CigarGuy]

2 hours ago, leech~~ said:

Holy craap. The very first guy made a big point!  I would print out this whole thread so you have this info available if you go to the County like the one guy suggested and I will as well.  You could be just circulating carbon monoxide throughout the place! 

 

"It is illegal - everywhere so far as I know - and with excellent good reason - that domestic air return cannot come from the same place that the combustion air to the furnace burners comes from.

Any interesting thing to know, and it is easy and safe for you to get, is the temperature of the room air temperature, the temperature of the return air actually going into the furnace, and the supply air temperature coming out the closest register to the furnace."

PHM

I talked to a HVAC guy and he said the current install doesn't pose a serious health concern. Lots of safely stuff on current equipment. Guess, I won't die from the furnace just yet. I've got co detectors in just about every room. I've been trying to find out if there's a HVAC specific inspection service company in the area and can't find any. Basic home inspection services don't specialize in all aspects of HVAC. For 12 years I was a " Certified Flooring Inspector" and was hoping the HVAC industry has a similar service out there.