Part one of a Two Part Install Starts Tomorrow

[jangell]

I am replacing this baby tomorrow

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http://i72.photobucket.com/albums/i191/jjangell/Furnace/photo2.jpg

http://i72.photobucket.com/albums/i191/jjangell/Furnace/photo.jpg

You all have been very helpful with my decision making process. I am looking for one more favor...I eventually will be installing a new 95% 2 stage furnace and a heat pump. Pat one, tomorrow will be the furnace and the inside coil.

Can anyone assist with a list of "things I should look for" prior to signing off on the install.

I have reviewed quite a few of the installs from the "wall" and I have a general idea as to what I should look for...Would really appreciate some specifics.

[BaldLoonie]

What thermostat? I'd want something that stages the gas backup, such as a Vision Pro IAQ.

[jangell]

What thermostat? I'd want something that stages the gas backup, such as a Vision Pro IAQ.

Honeywell visionpro 8000. Do I need the vision pro IAQ?

Simple system with an hp, 2 stage furnace and an electronic air filter.

[Roadhouse]

I like how you have the bbq lighter right there and ready, nice!

The only thing I would personally do is alter the location of the kill (light) switch that's currently mounted on the side of the unit. I'd mount it on the inner right wall stud, facing the unit and run wire into the unit from the switch.

I don't think it's a failable offense but still, if I wanted to cut power to the unit, I'd want to do so from a distance. It's how it's done around here. Not to mention when it comes time to remove the unit, it's easier to work with.

[Roadhouse]

The new gas connection should have a drip leg on it, before entering the unit. This is now code, not so when your old unit was installed.

A drip leg is meant to catch (by way of gravity as debris would be heavier than gas) any debris in the gas line feeding gas to the unit.

Pretty much it's an upside down TEE in the gas line, made of the same steel gas pipe and only an inch or two long.

[jangell]

The new gas connection should have a drip leg on it, before entering the unit. This is now code, not so when your old unit was installed.

A drip leg is meant to catch (by way of gravity as debris would be heavier than gas) any debris in the gas line feeding gas to the unit.

Pretty much it's an upside down TEE in the gas line, made of the same steel gas pipe and only an inch or two long.

What about using flex instead of black pipe?

I'm pretty sure they did not have flex in 1971.

[Roadhouse]

You can not go INTO a unit with flex gas line. I think it's either 6" or 8" that you must come out of the unit (so hard pipe from the gas valve inside coming out) with hard pipe not to mention you don't really have the room.

So an 8" or 10" or a 1' piece of pipe would be needed to screw into the gas valve which is located about 4" to 6" to possibly even 8" inside of the unit to have at least 6" sticking out.

From there they can do whatever they want and if they choose to use flex as the rest of the pipe might need to be re-run to be able to accomodate a drip leg, that's fine.

[BaldLoonie]

With 8000, can't stage the backup, have to use the board's timer which is far from the most efficient & comfortable way to do it. IAQ should have been planned.

[b26440510]

You can not go INTO a unit with flex gas line.

Inquiring minds want to know why that is. I know in my install instructions it is clearly stated, but it didnt seem that any of my installers knew that, and I had to "convince" them to not run flex to the valve body.

I think my manual said something about the possibility of the flex line possibly damaging the valve body's threads.

[jangell]

With 8000, can't stage the backup, have to use the board's timer which is far from the most efficient & comfortable way to do it. IAQ should have been planned.

Interesting. All of the proposals that I received...Including one from now banned seaton, had an Honeywell thermostat Model # 8320 as the stat spec.

And what does stage teh backup mean? Tring to become a bit ed u ma cated here as well

[Roadhouse]

Inquiring minds want to know why that is. I know in my install instructions it is clearly stated, but it didnt seem that any of my installers knew that, and I had to "convince" them to not run flex to the valve body.

I think my manual said something about the possibility of the flex line possibly damaging the valve body's threads.

A few things come to mind and this is just thinking aloud along with "if my memory serves me correctly" type of answers but first and foremost would be that flex could be cut by the sheetmetal of the cabinet of the unit so a gas leak/explosion could occur. The possibly ever so slightly vibrating of the entire cabinet of a unit as the blower kicks on and shuts off or ever so slightly adjusts in speed will not knock around a solidly screwed in steel bar as the flex can be manipulated as it's, well, flex,...and aluminum at that so thin, lightweight.

Secondly, I think that there might be some connection between the two different metals, aluminum and the steel from the bar threaded into the valve in which when tightened they compress to make a seal better than vs. two steel bar ends with pipe dope. Pipe thread sealant is not used at the gas valve for this case as you don't want to interupt that seal at that one connection, or not nearly as much comparatively.

[jangell]

Its not to late to request a different Thermostat...Should I have him put in the honeywell 9000/IAQ?

I don't have any IAQ type equipment per se (furnace, heat pump and an electronic air filter only)

[beenthere]

Honeywell visionpro 8000. Do I need the vision pro IAQ?

Simple system with an hp, 2 stage furnace and an electronic air filter.

The 8000 can't control both stages of your furnace. So the furnace's board will have to use its timer.

The IAQ can control the 2 stages of your furnace.

[jangell]

The 8000 can't control both stages of your furnace. So the furnace's board will have to use its timer.

The IAQ can control the 2 stages of your furnace.

Is it better to have the furnace's board handle the two stages or should it be done at the stat.

Surprised that everyone including season missed this nuance.

[beenthere]

Is it better to have the furnace's board handle the two stages or should it be done at the stat.

Surprised that everyone including season missed this nuance.

Thermostat.

Why go to second stage for 30 seconds at the end of a heat call.

[jangell]

Thermostat.

Why go to second stage for 30 seconds at the end of a heat call.

Hmmm. Thanks i think.

what does that mean?

[BaldLoonie]

First, a thermostat on the wall knows what amount of heat the house needs. It knows if you just turned the temp up. It knows if you are recovering from a setback. It knows how fast the house is heating up and that it is about to shut the system off. A timer in a board knows none of this. All it knows is that in 10 minutes it goes to high.

Now, on a cold morning, the idea of a 2 stage furnace is long run cycles on gentle, quiet low. Can't have that with a timer, you will time up in 10-12 minutes and stay there til satisfied. Then it will shut off. You'll start to feel cool, heat will start on low but instead of a gentle, quiet run cycle, it will time to high again. Over & over.

As you drive in the car and the car warms up, do you turn the heater up? Why not? That's what the timer on the board does!

[jangell]

First, a thermostat on the wall knows what amount of heat the house needs. It knows if you just turned the temp up. It knows if you are recovering from a setback. It knows how fast the house is heating up and that it is about to shut the system off. A timer in a board knows none of this. All it knows is that in 10 minutes it goes to high.

Now, on a cold morning, the idea of a 2 stage furnace is long run cycles on gentle, quiet low. Can't have that with a timer, you will time up in 10-12 minutes and stay there til satisfied. Then it will shut off. You'll start to feel cool, heat will start on low but instead of a gentle, quiet run cycle, it will time to high again. Over & over.

As you drive in the car and the car warms up, do you turn the heater up? Why not? That's what the timer on the board does!

Makes perfect sense. THANKS!

[Advanced Response]

are you having a true 2-stage unit installed or a convertable 2-stage unit installed?
I believe that you are getting a goodman unit correct?
Goodman has 2 models of 2-stage furnaces, which are the GMH(convertable 2-stage) and the GMV(true 2-stage)

On the GMH the 2-stage has no option to have 2nd stage controlled by the stat..
However on the GMV it is a must to have the 2nd stage controlled by the stat as the timer is dumb IMHO....

Goodluck
J

[jangell]

are you having a true 2-stage unit installed or a convertable 2-stage unit installed?
I believe that you are getting a goodman unit correct?
Goodman has 2 models of 2-stage furnaces, which are the GMH(convertable 2-stage) and the GMV(true 2-stage)

On the GMH the 2-stage has no option to have 2nd stage controlled by the stat..
However on the GMV it is a must to have the 2nd stage controlled by the stat as the timer is dumb IMHO....

Goodluck
J

You are correct. It is a Goodman GMV