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Old 01-02-2009, 09:23 PM   #16
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Confirming correct gas pressure for new furnace


Any of the Bacharachs.

Starting price, is 500 bucks.

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Old 01-02-2009, 10:13 PM   #17
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Confirming correct gas pressure for new furnace


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Any of the Bacharachs.

Starting price, is 500 bucks.
The Fyrite Tech 60 measures CO, O2 and stack temp.

Is that sufficient? or do I need something that measures additional gases as well?
See link below

Key1

http://www.bacharach-inc.com/fyrite-tech.htm
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Old 01-02-2009, 10:15 PM   #18
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Confirming correct gas pressure for new furnace


With that kind of loot I would have to run a few static pressures in the neighborhood to get my money back

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Old 01-02-2009, 10:21 PM   #19
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Confirming correct gas pressure for new furnace


I have the Tech60.
Works fine.

Like most digitals, it does a calc to determine CO2, instead of actually measuring it.

Thats not a real problem.

Yea, for a one time use, its a bit much.
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Old 01-02-2009, 10:22 PM   #20
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Confirming correct gas pressure for new furnace


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With that kind of loot I would have to run a few static pressures in the neighborhood to get my money back

Key
Just found the same model for $399.00 ...I'll keep looking
http://cgi.ebay.com/BACHARACH-FYRITE...1%7C240%3A1318
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Old 01-02-2009, 10:26 PM   #21
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Confirming correct gas pressure for new furnace


Thats a good price.
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Old 01-02-2009, 10:39 PM   #22
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Confirming correct gas pressure for new furnace


My ultimate goal is to get the maximum efficiency out of my system.
It has been suggested to me that I can improve efficiency by simply increasing my Temp Rise (from 45 to 62).

I like this idea because I can increase the temp rise by slowing my blower.....which in turn lowers my already high static pressure so I get multiple gains. One thing I am unsure of is if I lower the blower speed from the current 1180 CFM's to the lowest setting of 900 CFM's......will that be sufficient airflow to still heat my home? Even though the air temp will be 17 degrees hotter . I look forward to testing all of that tomorrow.
stay tuned

Time for me to get some shut eye

Key
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Old 01-02-2009, 10:56 PM   #23
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Confirming correct gas pressure for new furnace


The amount of air flow a room really needs, varies with the outdoor temps, the set temp of the stat, and the amount of BTU's in the air.

1180CFM, 45F temp rise=57,348BTUs.
900CFM, at 62F temp rise=60,264BTUs.
That would be a 5% increase.

My guess, is that if you slow the air flow to 900CFM, you'll have a temp rise of 59F(+or-2%).Varies with thermometer accuracy.

Thats my prediction.
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Old 01-03-2009, 10:27 PM   #24
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Confirming correct gas pressure for new furnace


I took the advice of another pro and checked multiple places for temp rise. I found a location a little hotter at 47F so I am using that new location (in a main trunk right after the plenum) as my base line as that is the hottest air coming out of my unit.

So my new starting baseline is 47F and ~1180 CFMs.
Initially, I dropped the blower speed to 900 CFMs and the temp rise jumped to 64F which is a little to close to my 65 max upper limit.
So I set the blower to the next lowest speed of 1000CFMs. The temp rise was a reasonable 57.5F. I will see tonight when the outside temp drops to 21F if this new lower airflow will heat my home.

Additional side benefits of the lower airflow include my static pressure dropping from 0.65 on heat to 0.48 and my wattage draw dropping from 365 to 260.

When I get my new toys I will check the efficiencies

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Old 01-04-2009, 06:36 AM   #25
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Confirming correct gas pressure for new furnace


For actually doing efficiency test to see if your improving, or decreasing efficiency, when making CFM adjustments.

You need to take readings in multiply places.
As you increase or decrease air flow. You change the pattern(even changes across the heat exchanger).
So you could get more air flow in one area then another. And your temp reading will be off some.

EG:
1180CFM temp rise 48=61,171BTUs.
1180CFM temp rise 47=59,896BTUs.
Difference of 1,275 BTUs

When adjusting manifold pressure only.
The air flow pattern doesn't change, so you can use one test area.
As the temp rise will be the same increment

Generally, the temp in the trunk line is best to use. Since the air has mixed, so you don't get fooled into a false air temp.

Your trying to find the mean/average temp of the air. All 1180, 1000, or what ever CFM of it. Not just a few 100 CFM of it.
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Old 01-04-2009, 08:14 PM   #26
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Confirming correct gas pressure for new furnace


Quote:
Originally Posted by beenthere View Post
For actually doing efficiency test to see if your improving, or decreasing efficiency, when making CFM adjustments.

You need to take readings in multiply places.
As you increase or decrease air flow. You change the pattern(even changes across the heat exchanger).
So you could get more air flow in one area then another. And your temp reading will be off some.

EG:
1180CFM temp rise 48=61,171BTUs.
1180CFM temp rise 47=59,896BTUs.
Difference of 1,275 BTUs

When adjusting manifold pressure only.
The air flow pattern doesn't change, so you can use one test area.
As the temp rise will be the same increment

Generally, the temp in the trunk line is best to use. Since the air has mixed, so you don't get fooled into a false air temp.

Your trying to find the mean/average temp of the air. All 1180, 1000, or what ever CFM of it. Not just a few 100 CFM of it.
Thanks as always for the additional insight. I'm expecting the manometer Wednesday. Not sure if I can afford the combustion meter yet .

For all, the reduced air flow worked great. My home was succesfully heated when outdoor temp dropped to 21F. Static pressure is now down (0.48) under nameplate value .

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Old 01-04-2009, 08:45 PM   #27
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Confirming correct gas pressure for new furnace


Can never have too many toys/meters. LOL. Probably sounds quieter now that the static pressure/velocity is within specs.
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Old 01-04-2009, 08:56 PM   #28
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Confirming correct gas pressure for new furnace


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Can never have too many toys/meters. LOL. Probably sounds quieter now that the static pressure/velocity is within specs.
Can barely here it running unless I stand next to it. Although noise was never an issue since the furnace is in the basement and the return air is dispersed across 6 return grills.

One nice feature of the reduced airflow that finally made my wife support what I am trying to do is that now the air coming from the supply registers feel nice and hot instead of warm.

Key1
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Old 01-05-2009, 07:12 PM   #29
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Confirming correct gas pressure for new furnace


Now we know who's the Boss. If Mama ain't happy nobody is happy. (according to doc phil).
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Old 01-05-2009, 09:09 PM   #30
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Confirming correct gas pressure for new furnace


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Now we know who's the Boss. If Mama ain't happy nobody is happy. (according to doc phil).
You got that right.

Hey tell me what you think of my latest idea. Since I already have a standard wireless outdoor temp sensor upstairs, Rather than continue with redundancy, I am considering moving my new wired outdoor temp sensor that is tapped into my tstat to a location inside the trunk duct about a foot from the plenum so I can easily view temp rise/outlet temperatures at a glance anytime I want. . Genius or Insanity?

And yes we have already established I have too much time on my hands....

Key1

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