New furnace


  #1  
Old 06-29-05, 06:08 PM
Concretemasonry's Avatar
Member
Thread Starter
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
New furnace

Just bought a 25 year old townhouse with a 25 year old Tappan 80,000 BTU furnace. I assumed a new furnace was coming soon. The AC is about 4 years old, so it should be O.K.

Fortunately an inspection revealed a cracked exchanger, so I have the summer to get a replacement put in.

What do I look for and what should I avoid? I assume that I am in the range of 80,000 BTU or possibly less depending of the efficiency (if it measured by input).

I think a high efficiency is out because of problems running condensate and vent piping to the exterior. Also I only have a roof and two walls exposed to mother nature.

In a previous home I had a lot of problems with belts. Are direct drive fans used?

I have an open stairway that makes uniform temperatures difficult to maintain and I think a two zone system would be difficult to go to. Can I use the fan (possibly 2 speed) to help maintain more even temperatures?

I just was told the AC condensate is leaking out - I hope it just a plugged drain or what? 90 degrees with 90% makes everything happen.

Dick
 
  #2  
Old 06-30-05, 12:56 AM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
if you condo won't let you do the side vent 90%, can go up the roof with the vent.. As for drain, it can use the same drain as your A/C use.

Otherwise, non above will work you can use 80%.

For best comfort, and quiet... Look into Variable Speed blower w/ 2 Stage-Heating.

You can get 2-speed blower, but most of the time when you run the fan "ON", it runs on a higher speed, where Variable speed runs slower. Blower now days are direct drive.

I have a split level home w/ open foyer/stair way, and temps turns out pretty even in the house from the variable speed blower. Best thing about it, You hardly hear it running.

if you go 2-stage heating, MAKE SURE you get the 2-stage t-stat as well.

When you get a dealer in to qoute you a new system, make sure the do the heat lost/gain on the home... (Manual J) Lot of time the older system are way over sized!

More likely the drainline or coil is plugged.
 
  #3  
Old 06-30-05, 07:31 PM
Concretemasonry's Avatar
Member
Thread Starter
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
New furnace

Thanks for the great answers!! Everything makes sense and I appeciate the tip about the 2 stage stat. Now to find the right equipment and installer. They say summer is a good time to buy a furnace if they can schedule the installation around AC service and the weather.

You tip on the condensate was good. It was close to a plugged drain line. My wife moved the glazed panel for the screen/storm door and set it on the flexible drain line. With the heat and time the restriction eventually plugged with debris. A cheap fix finally.

Thanx!!

Dick
 
  #4  
Old 08-19-05, 05:25 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
Dick,

I see you've made comment on how well you like your system.. Glad to hear that!

Did you just end up with the 80% system or did they make the 90% work??

What type of t-stat you get?

Are you finding that you run the a/c at a higher temp then you used to do in the past??
 
  #5  
Old 08-19-05, 06:08 PM
Concretemasonry's Avatar
Member
Thread Starter
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
New furnace

I went with an 80% system because of the venting problems in my townhouse (by the front door?) and the limited exposed walls (only 2 of 4 sides). It didn't seem like the 90% was worth it for me, even in Minnesota. I went from 80,000 BTU input @60% to 66,000 BTU @ 80% since the next step down was too much. Possibly oversized, but I do have the two stage burner.

I was able to use the setback t-stat I had bought a couple of months earlier. With a Rheem system I would have to use their recommended t-stat. With mine, they claim I can go on-off-on to bump up the continuous fan a notch. - I have bothered to try it since it works so well. It is so soft and quiet I don't know if I would notice it easily.

I haven't bumped the temperature too up much (3 degrees), but it has done a much better job of reducing the humidity inside. Even when the evening temps get into the 60's, I just let it idle rather thay let in the humidity. I did shut it down when it went from 95 to 54 the next morning (it was 31 only 200 miles north).

I am happy so far and I hope that it works as well heating. From what I have seen, it should. Why didn't they go to DC variable fans 20 or 30 years ago?

Duck
 
  #6  
Old 08-19-05, 07:39 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
I was able to use the setback t-stat I had
Is this a 2-stage stat???

I would strongly suggest getting a 2-stage stat vs the regular single stage, and using the "timer" on the furnace..

Why do i say that, a few reason..

-if you use set back, the system will start off on low stage then after X amount fo time it will kick into 2nd stage... It may lead to over shot in temp.

The 2-stage stat will bring the system into 2nd stage right away, and help get recovery going quicker, once the temp gets near set point, the system backs down to low fire, and slowly reach up to set point.. leads to more even and softer reach of temp.

-On a mild day, system on regular t-stat, system may run x amount of time then kicks into high fire, may 'short cycle" the system. 2-stage will not go into high fire unless the temp has drop.


-If it's really cold (Like we had around Christmas) the system will run on low fire for a longer time (I've seen mine run as long 2 hours) before it shut off. Longer run time leads to more even temp in the home.. My neighbor behind me has the same lay out as mine for home, and they said the bedrooms were cold, familyroom was hot*they have the old single stage) and mine was warm.and even all over.

I hope this helps??
 
  #7  
Old 08-19-05, 08:09 PM
Concretemasonry's Avatar
Member
Thread Starter
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
New furnace

Thanx for the insight.

I think I will wait until the first cold snap and see how it operates.

If and when I decide to swap out the t-stat what brands are good and where might I get one in the Mpls/St Paul area?

Dick
 
  #8  
Old 09-11-05, 03:46 PM
Jay11J's Avatar
Member
Join Date: Sep 2001
Location: Rochester, Minnesota
Posts: 16,984
Upvotes: 0
Received 0 Upvotes on 0 Posts
I found the link for the "Demo" of the t-stat..

I suggest the Vision pro
http://www.hotfreshcool.com/innov8/
 
  #9  
Old 09-13-05, 08:48 AM
Concretemasonry's Avatar
Member
Thread Starter
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
Thanks

Thanks for the demo -

I will look into it.

Dick
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: