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Old 01-26-2012, 12:43 AM   #1
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Question about changing to high efficiency gas furnace


Dear all, how are you doing?

We are thinking about switching to high efficiency furnace. However we understand that it will produce gallons of water per day. The current location of the furnace is in the garage without any sewage drain. Is there any way that we can circumvent the problem? For high efficiency furnace do people usually just switch the location of the furnace so that it's easier to install, or we are still stuck with the current furnace location? Do we have to replace the duct as well or can we use the current ones, and if we are using the current ones and want to put the new furnace in other places, is it easy to do (by redirecting the duct)? Thanks!

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Old 01-26-2012, 01:13 AM   #2
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Question about changing to high efficiency gas furnace


A condensate pump can pump the condensate down a hose to a remote drain location.
The ducting will probably stay pretty much the same unless you've already had duct restriction issues that need to be addressed.
When people ask about relocating a furnace, my first impulse is to say money gets you any change you want. Ducting, air supply, venting, electrical, gas piping , condensate line all get modifyed to go to the new location.
The one thing that a high efficiency furnace frees you up location wise is your connection or need to be near the old B Vent or chimney.

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Old 01-26-2012, 09:22 AM   #3
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Question about changing to high efficiency gas furnace


What he said.

A condensate pump plumbed to a sink would be ideal.
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Old 01-26-2012, 10:55 AM   #4
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Question about changing to high efficiency gas furnace


As long as it does not ever get below freezing in the garage U should be fine. If it does then the water in the furnace can freeze and a backup electric heater should be installed to prevent damage.
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Old 01-26-2012, 02:40 PM   #5
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Yuri this OP lives in California. The ain't even going to let them drain acid condensate into the yard.
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Old 01-26-2012, 03:02 PM   #6
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I doubt it ever gets below freezing but other posters read these and need to know if they are planning the same project. Apparently there are more people in Calyfornia than all of Canada. Must be a crowded place.
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Old 01-26-2012, 04:56 PM   #7
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Originally Posted by yuri View Post
I doubt it ever gets below freezing but other posters read these and need to know if they are planning the same project. Apparently there are more people in Calyfornia than all of Canada. Must be a crowded place.
Dang...your country better get busy and make some babies.
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Old 01-26-2012, 06:05 PM   #8
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half the darn thing is muskeg and bush and inhospitable. not so much trouble with crime in the winter as it is too damn cold to go anywhere.

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Last edited by yuri; 01-26-2012 at 07:07 PM.
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Old 01-31-2012, 12:53 AM   #9
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Question about changing to high efficiency gas furnace


Ha, you guys are funny. Thanks for the video yuri..

Seriously, here is our situation. We have a 13 years old "Day & Night" furnace which currently has chamber overheating problem and the furnace will shut down itself from time to time. We hired two HVAC professionals to take a look.

The first professional said that there are a few factors that can create the issue. The cold weather we have been having lately makes creating the exhaust current very hard in the mornings. Another thing would be a change is usage patterns between the furnace and water heater. When the water heater and furnace are running together (they share the same flue), the heat generated from both units helps both units to vent. If the furnace is being used at times the water heater is not, then the furnace has to create the entire exhaust draft on it's own. This can cause the vent safety switch to trip. The vent system we currently have is not 100% installed correctly (the horizontal exhaust flue was not tilted enough), and is venting exhaust fumes into the garage and will eventually destroy the inside of the existing furnace. They quoted US$3,300 to replace the existing terra cotta flue and install the new double wall flue.

The second professional suggested that we should just change the whole furnace to a high-efficiency one, and they quoted us $2,600 (labor plus parts). They propose to use a Bryant high-efficiency furnace, and to install a condensate pump so that it can pump the condensate down to a hose and then to a remote drain location. In this case, I don't think he is looking to use the existing flue for the high-efficiency furnace.

We had very good experience with the first professional, and trust his opinions. However, if we go with the first route, we will still end up with a 12 years old furnace, which I don't know when it will just stop working. For the 2nd professional, we don't know him that well (he is also a licensed professional), but if his plan works, then we end up with a NEW high-efficiency furnace which potentially could last longer. So what do you folks think? Which solution is better and if it were you, which solution would you pick and why?? Many thanks!

Last edited by ohman; 01-31-2012 at 01:01 AM.
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Old 01-31-2012, 02:01 AM   #10
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Just how cold is it getting in San Francisco?

If It is true that your furnace exchanger is overheating then there are numerous furnace repair options to address that.

You seem to just be saying that you are getting vent spillage but the chimney explanations makes little sense.
If this vent limiting hasn't always been going on then what is different now?
A chimney that will vent two appliances, but not one, is usually too large but they are suggesting breaking up a liner to gain the space to put in a double walled liner.
How long is the horizontal section that is not inclined enough (is it dipping lower towards the chimney) and is it B vent?
Are you getting enough fresh air into the "garage" for the chimney to vent properly? Is a Clothes dryer, or fan in the house creating too much of a negative pressure for the chimney draft to evercome.
Is there a return air too close to the furnace?
Is an old chimney clean out cover open?

I wonder if either $$$$$ choice offered to you has explored the other possibilities yet.

Last edited by how; 01-31-2012 at 02:10 AM.
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Old 01-31-2012, 02:23 AM   #11
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Quote:
Originally Posted by how View Post
Just how cold is it getting in San Francisco?
Thanks so much for your help, how...

According to weather.com, SF currently is 47 degree F.

And yes we were wondering the same thing about if this vent limiting hasn't always been going on then what is different now? One theory (according to the 2nd professional), is that the unit is getting old, so the blower motor is getting weak so the exhaust are not pulled out quick enough. The horizontal section that is not inclined enough is about 8-9 feet long. It is slightly rising toward the chimney (from the furnace) but only has about 10-15 degree angle, then suddenly at the final 1/2 feet it dips (10 degree) at the connection to the chimney vertical section (oh boy I wish I have a picture with me)... The furnace is located in the basement, and the clothes dryer is located at 1st floor so they are not close to each other.

BTW, WHY would return air too close to the furnace also potentially be a problem with this issue? Just curious, thanks!

Last edited by ohman; 01-31-2012 at 02:43 AM.
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Old 01-31-2012, 07:03 AM   #12
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47 F man I won't see that until May 1st. I have had problems with that furnace (Carrier version) doing that same thing and they are very sensitive to venting and DO NOT like horz venting unless it is B vent and sloped and a B vent liner. Sorry. What is happening is the air in your oversized chimney is getting stagnant/losing its natural draft and the furnace and ventor cannot overcome that or produce enough heat fast enough to get the chimney to draw properly so the tech is correct and smart (lots don't know that or how chimneys REALLY work).

You can suck in CO, carbon monoxide if it spills and gets sucked into the return air.

I would go with plan B as you are getting a new furnace, that unit has had circuit board failures due to bad solder joints and boards usually last 10 yrs and start failing on lots of brands. Going to be a repair $$ pit IMO.

Get a quote from the first guy on a new furnace as it sounds like he knows his stuff and does good work. Beware that there are 4 different quality levels of furnaces like chevy cavalier/malibu/buick/cadillac so you need to get even models to give him a fair chance. we may be able to compare them if you post them here. we don't do pricing.
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Last edited by yuri; 01-31-2012 at 07:11 AM.
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Old 01-31-2012, 11:14 AM   #13
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Question about changing to high efficiency gas furnace


Is the horizontal section, double walled (B vent)?

A return air grill in the furnace area can cause a negative pressure for the chimney draft to fight against.

If the inducer motor is failing and causing a problem that is new, what is the cost for a replacement ID assy?
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Old 01-31-2012, 11:24 AM   #14
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what person installs an 80% furnace with no liner???????
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Old 01-31-2012, 01:08 PM   #15
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Quote:
Originally Posted by yuri View Post
I would go with plan B as you are getting a new furnace, that unit has had circuit board failures due to bad solder joints and boards usually last 10 yrs and start failing on lots of brands. Going to be a repair $$ pit IMO.

Get a quote from the first guy on a new furnace as it sounds like he knows his stuff and does good work. Beware that there are 4 different quality levels of furnaces like chevy cavalier/malibu/buick/cadillac so you need to get even models to give him a fair chance. we may be able to compare them if you post them here. we don't do pricing.
Thanks for the comments. The problem for the first guy is they are a family owned business and they are so busy that they don't even return our phone calls or emails anymore.

So for the 4 different quality levels, can you elaborate this a little bit more? The house is about 3,600 square feet (3 floors house plus a basement) and the 2nd professional recommended a Bryant one (not sure about the model# though). I google'd it and it seems that Bryant ONLY has one model (Evolution System The Plus 90i or PREFERRED SERIES PLUS 95i ??) that's count as high efficiency gas furnace? How would you consider a Bryant gas furnace then, is it a chevy or cadillac or somewhere in between? Thanks!

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