Last minute installation questions

[rdtompki]

I'm under contract for an 80K BTU/hr 80% two-stage York Affinity replacement of my existing furnace. This is a local contractor who had bid the same job in mid-05. I liked him during the original go-around, but couldn't get at least two bids I was comfortable with. This time around I said the heck with multiple bids; he's local and I was comfortable with him even in the original go-around.

The 80% configuration is to avoid running a condensate line. This same contractor had bid a 90% as a ground floor instal. Our climate is quite mild (San Jose, CA) and in the winter I set the thermostat to heat for only 2 hours am and two hours pm. Would there be any advantage in my environment to go with a variable speed 80%? I understand the variable speed can be a bit quieter especially during startup and will save some on the electric bill, but given that the furnace runs for so few hours is the additional expense worth while?

Also, I understand that a true two-stage 'stat is preferred over using a timer to control the stages. Agains, in my situation is this likely to make much of a difference?

Rick

[Mstrav]

good old holister, born and raised in san luis, then nor cal, quick stop in vegas for 10 years, back to san luis for a few years now in Idaho.

now that you know me, I have some questions for you:

do you have a/c, or will you ever get it?

yes use a 2-stage t-stat for enhanced unit control, you can control when second stage starts, vs a timer in the unit. get a good t-stat and learn how to use it, they come with a book, read it. make sure the t-stat is backlit as well, this is 2007, not 1985. check with the gas, power company and city for rebates. your invoice is proof of purchase. good to do your furnace now instead of dec.

variable speed where your at if you are not ever adding a/c is a hard one. did you think about any air filtration? Is he replacing the entire vent through the roof including cap and colar?

thanks, matt (I love riding in holister on my rhino and my bike)

[rdtompki]

I won't ever get A/C as our climate is too mild. His bid includes using the existing vent (although the high efficiency ground floor option would have required a PVC vent). The current vent is shared with a water heater which has been talken out of service and will be removed.

As far as air filtration, I haven't thought about it much. We are downwind of thousands of acres of row cropping as this is a heavy ag area and there is plenty of stuff in the air that just blows its way in through open windows. I can see one advantage of variable speed would be the ability to run the furnace (or AC I would assume) at a very low heat/cool level to keep the air filtered.

Rick

[Mstrav]

yes but the cheap filter it comes with would not perform well, even on ag dirt. if you want filtration yes the variable can be run on a low setting multiple times per day or continous on a low setting where you may not even notice it being on. yes 90%+ uses pvc for its vent

good luck, matt

[rdtompki]

The installation is almost complete and generally I'm pleased with the work. Some minor duct work improvements were made along the way which will supply more air to a large master bedroom. The location of the new return is in ceiling of a short hallway near the master bedroom/bath, a second bath and two other small bedrooms. The only question I have about the installation is the manner in which the return grill was connected to the furnace.

The new attic furnace is horizontal and the return is opposite the direction of the grill. The installers used as very large flexible duct for this run. I have no problem with the basic material as this is almsot universal in my area, but would it have been better practice to build a sheet metal box "dogleg" on the return end of the furnace to avoid having a u-turn in the large duct?

I'll post a picture when I get a chance.

Rick

[Mstrav]

As long as it is suported and makes a nice radious turn you will be fine. to make that out of metal in an attic would 1) cost more money, 2) be harder to do on a retrofit. Is there any metal box on the return side before the flex starts or did he blank off the back off the furnace and hook the flex to that? I like 2 turns on the return just to take the sound of the blower away.

most important since you said it is suspended is he needs to put seismic braces / straps on the unit and make sure it is attached to the trapeeze. mention this to the contractor. Did you get a "good thermostat" as well? post the model of what he is offering here. also check on rebates from the gas company and power company.

which unit did you go with?

A pic would be nice!

matt

[rdtompki]

Matt,
I've attached a few pictures of the installation. Looks like the furnace is properly secured and such. The radius on the return doesn't look to bad to my very unprofessional opinion. The access to the furnace is good (I had put in the catwalk last year for which I'm sure they were very thankful). The thermostat is a Braeburn which is supposed to be a two-state although I confess to not having looked at the instructions yet.

Rick