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#21 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 568
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Re: Combustion testing
Hard to say if that would help a lot or not.
Although the coil is a pressure drop/resistance to air flow. Would a 6" bypass configured like that move more then 100 CFM is the question. The answer would be. Only if the coil was the only interference to air flow to the house. As in. If you having trouble with the rooms on the end of the duct system. It wouldn't help. Since most of the extra air would be forced out the first supply runs. And very little would reach the far supplies.
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#22 |
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Member
Trade: Installation and service
Join Date: Jun 2009
Location: Chicago South Side
Posts: 82
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Re: Combustion testing
I am mostly thinking of this to make it easer to move the cfm. Why work harder all winter and use more energy forcing all the air through a coil. 6" is only a example it could be any size square or round as long as it could seal tight durring the summer. There is more winter than summer here. I dont know what the energy savings would add up to but it couldnt hurt.
A over sized plenum with a removable slide on the overhang would work also. Kinda like winter / summer dampers when the old seperate watercooled a/c packages were used in combination with the furnaces. |
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#23 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 568
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Re: Combustion testing
A PSC motor uses less electric at higher static pressure then it does at lower static pressure. Because it is doing less work, since it is moving less air.
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#24 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 568
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Re: Combustion testing
A 1 HP power motor under full load. In therory is moving 2481CFM. Ore, 33,000 pounds of air a minute.
Increase static pressure so that it is only moving 10,000 pounds of air a minute. And its only working as less then a 1/3 HP motor. And its amp draw will drop accordingly.
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#25 |
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Member
Trade: Installation and service
Join Date: Jun 2009
Location: Chicago South Side
Posts: 82
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Re: Combustion testing
Assuming we are able to move the correct cfm through the evap on high speed oridginalyl but now with the lower static it can be done on med-high. Wouldent that be a lower amprage?
On the other hand if we are now moving more air and drawing higher amprage. We would now be delivering more heat now that we are closer to designed cfm. This should make the overall operation more efficient shouldent it? |
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#26 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 568
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Re: Combustion testing
If a blower moves more air on med high speed then on high speed. It is using more wattage at med high then at high speed. Since it is doing more work.
1,000 CFM with a 50 degree temp rise is 54,000 BTUs. 800 CFM at a 62.5 degree temp rise is 54,000 BTUs. 600 CFM at a 83.4 degree temp rise is 54,000 BTUs. Its the combination of CFM and temp difference that determines BTUs delivered.
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#27 |
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heatman
Trade: residential hvac
Join Date: Dec 2010
Location: mass
Posts: 4
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Re: Combustion testing
what makes and models do you people use, and have you had good experince
i am going with an E instrument is anyone useing this product, if so let me know if it is a good machine thank you Last edited by dan22; 12-05-2010 at 09:55 AM. |
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#28 |
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Senior Member
Trade: Service/Installation
Join Date: May 2009
Posts: 568
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Re: Combustion testing
Bacharach Tech 60, and Infinite.
Don't know what a bad experience with one is. So I think I have only had good experiences with them.
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