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-   -   Dialing in a new furnace (http://www.diychatroom.com/f17/dialing-new-furnace-120368/)

MNice 10-17-2011 11:14 AM

Dialing in a new furnace
 
Can this be done by a diy'er?

Doc Holliday 10-17-2011 11:15 AM

What are you looking to do exactly?

Doc Holliday 10-17-2011 11:40 AM

Hello? What does "dialing in a new furnace" mean exactly?

MNice 10-17-2011 12:00 PM

The company from who I bought it from said I would need them to come once its up and running to dial in the settings. My understanding is adjust the head pressure ect because it a new furnace.

Doc Holliday 10-17-2011 12:07 PM

Quote:

Originally Posted by MNice (Post 750510)
The company from who I bought it from said I would need them to come once its up and running to dial in the settings. My understanding is adjust the head pressure ect because it a new furnace.

In cooling mode this would be true, heating not so much. We're talking furnace, not heat pump right? So there is no head pressure at all, only in cooling mode. You don't put refrigerant gauges on a furnace, only a condenser and that condenser only runs in cooling mode. Refrigerant and air flow concerns pressures, head and low. In cooling mode the blower runs on high.

There really isn't any dialing in on heating mode. You have a temperature rise while the blower is on low speed and that's about it.

At this point I'd just let the guys who installed it come on back out as it's their job and they already said they will. Not to mention you paid for their time. And if you mess with anything it can lead to the voiding of warranties.

MNice 10-17-2011 01:12 PM

No they didn't do any install I did the install which makes it more money out my pocket. Hence the reason I asked, cause if they truly needed to come out then id fork out the $$$.But if it's not true then id start to wonder if he's tryin to take for a ride. Would there need to be adjustments on the burners?

And yes its a furnace. Comfort-aire 95% efficiency, 2 stage, dc variable speed blower.

JJboy 10-17-2011 02:57 PM

You can do the final adjustment but you need manometer, thermometer etc. You need to check if the blower motor speed is correct for the CFM, static pressure etc.

Doc Holliday 10-17-2011 03:56 PM

Quote:

Originally Posted by MNice (Post 750556)
No they didn't do any install I did the install which makes it more money out my pocket. Hence the reason I asked, cause if they truly needed to come out then id fork out the $$$.But if it's not true then id start to wonder if he's tryin to take for a ride. Would there need to be adjustments on the burners?

And yes its a furnace. Comfort-aire 95% efficiency, 2 stage, dc variable speed blower.


More than likely they are trying to get a bit of work (money) from the deal. If no refrigerant lines were opened, such as when an evaporator or condenser is replaced, and your system didn't have a refrigerant leak before hand then your pressures will most likely even out near the same as it was before. Not saying that it's a bad idea to have a company come out and check the entire system out both in heating and in cooling mode, they should do the basics such as gas and static pressure and WITH ALL COILS VERIFIED UNOBSTRUCTED OR DIRTY check the nominal charge, I'm just not certain that it'll make a difference if it already was and still is nominally charged and you have the correct temperaure drop in cooling and rise in heating. We'll never know unless they come out and know what they are doing.

You might find this useful, how to figure nominal charge, simplistic.
http://www.youtube.com/watch?v=HvXuh8MMIiE

MNice 10-17-2011 05:31 PM

Quote:

Originally Posted by JJboy (Post 750629)
You can do the final adjustment but you need manometer

Sarcasm?:eek:

The entire unit was relocated in our basement. We have new Furnace, Cased A-coil, Line set, & condenser. The AC is probably going to wait til spring to be in stalled. But with the weather cooling down the furnace is a must. The only thing im worried about right now is getting the furnace up and running for heat.

JJboy 10-17-2011 05:36 PM

Quote:

Originally Posted by MNice (Post 750721)
Sarcasm?:eek:

The entire unit was relocated in our basement. We have new Furnace, Cased A-coil, Line set, & condenser. The AC is probably going to wait til spring to be in stalled. But with the weather cooling down the furnace is a must. The only thing im worried about right now is getting the furnace up and running for heat.


http://www.youtube.com/watch?v=xglc9MDPatM :thumbsup:

Marty S. 10-17-2011 06:40 PM

Bare minimum start up on a new furnace should include setting gas pressure,setting blower speeds for temp rise( high is not always the correct speed for cooling nor is low always the correct speed for heating), checking static pressure,making sure the condensate drain works and making sure the flue is sized and supported correctly. A really good company will use a combustion analyzer to "dial in" for optimum performance.

hvac122 10-17-2011 06:45 PM

You need the gas pressure checked along with the temperature rise.
The variable speed blower also needs to be set up and airflow varified.
If this is what they intend to do then I would have it done. Call and ask them.

Doc Holliday 10-17-2011 07:01 PM

Quote:

Originally Posted by Marty S. (Post 750772)
Bare minimum start up on a new furnace should include setting gas pressure,setting blower speeds for temp rise( high is not always the correct speed for cooling nor is low always the correct speed for heating), checking static pressure,making sure the condensate drain works and making sure the flue is sized and supported correctly. A really good company will use a combustion analyzer to "dial in" for optimum performance.

Are you saying that high is sometimes best for heating and low is sometimes best for cooling? Do tell..

beenthere 10-17-2011 07:35 PM

Quote:

Originally Posted by Doc Holliday (Post 750784)
Are you saying that high is sometimes best for heating and low is sometimes best for cooling? Do tell..

Many areas need far more heat then they need cooling. So they may have a 80,000 BTU furnace, and a 2 ton A/C. So they may need 1200 CFM for heating and only 800 CFM for cooling.


Gas furnace should be set up with a combustion analyzer.

Doc Holliday 10-17-2011 08:12 PM

Quote:

Originally Posted by beenthere (Post 750802)
Many areas need far more heat then they need cooling. So they may have a 80,000 BTU furnace, and a 2 ton A/C. So they may need 1200 CFM for heating and only 800 CFM for cooling.


Gas furnace should be set up with a combustion analyzer.

So the blower on heating mode is on high speed in that situation, is that correct? And the blower is on low for cool?


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