90% er's in attic

[ductdog]

Just want some thoughts on putting 90% condensing furnaces in unheated attic crawl spaces.
YES...and it gets worse!!!
The climate is is the north-east US of A where it falls below freezing in the winter....and for extended periods of time.
ok...it gets worse...they normally have an A/C coil attached and he insists on putting condensate pumps in the space that vent through an unheated eve...
yes..it gets worse...in many cases the homes are un-occupied in the winter and setback in temperature...
It gets worse...but you have the general idea.
The reason he states he does this is because the builder " insists on the efficiency of a condensing furnace.
Mind you...I'm not for this. By the time I get to it to commission the startup or fix it...it's to late!!!
I'll get a "make it work".....and why is the ceiling wet and falling in again.
Is there something I'm missing to make this kind of setup work?????...other than remove the traps?...which I refuse to do, because it vents the CO into the attic above the living space from the furnace condensate lines.

incompetence is curable...stupidity isn't.....
What am I missing?

[key]

you have a delemma, You don't agree with the customer's request and yet you are still pondering doing the job. Where I am located, there are gas codes against such an installation.

[jacob perkins]

Originally posted by ductdog
Just want some thoughts to make this kind of setup work?????...other than remove the traps?...

Not saying this will work,but...
I have heard about some "waterless traps" that use a ping pong ball or something.Robo,I think posted a link for these awhile back...dont know if they are rated for this application...hell, I have never seen one...
good mornin' ,and good luck.

[t527ed]

no condensate pumps, self regulating heat tape on drains. been doing this over 20 yrs in nj, never had one freeze.

[rimek]

The reason he states he does this is because the builder " insists on the efficiency of a condensing furnace.

Then have the builder create a conditioned, insulated space in the attic for the furnace and heat-tape the drain components that run outside of this insulated area.

[wyounger]

Sure you can do it. You just build the house differently.

If you want a 90% in the attic, you insulate the roof deck instead of the ceiling- like a vaulted ceiling but with no drywall. No attic vents, the attic is just another room inside the building envelope. Finally, the condensate has to drain inside, into the plumbing, or that's going to ice up.

Yeah, heat tape works, but you're better off not depending on the power being on at all times. Granted everything will freeze up if the power goes out for long enough, but if you put a pipe in a freezing space with heat tape, that one is going to freeze way before the all ones inside the building envelope that don't have heat tape.

[johnsp]

Without power, the furnace won't be running anyway, so what's the problem? Extended outage might cause a water pipe freeze, so a condensate leak would be the leaat of my worries.

[HVAC Pro]

I guess it would be a problem if the trap froze while power was off. When the power is restored, the split trap would start spewing.

[ductdog]

OK....ok keep trying ....I don't hear anything foolproof...
These are really expensive houses. You would think the builder would want them right...it's his rep also..
Haven't heard the magic answer yet......
The 2 solutions I presented ....as was also suggested...is to build them into an insulated room.
my 1st solution was to rip them OUT...and to replace em with 80% er's and kill the idiot that put them there in the 1st place.

I've seen the ping pong traps...but I dont think they are approved in Massatwosh-ts.
I have used ezy-traps on the coils with the sensors and those work great...but wont solve the furnace condensate issue..or make the condensate pump go away...
Maybe I could move em over the upstairs bathtub.
Thanks...but keep goin...

No matter where ya go...there ya are

[2hot2coolme]

Sounds like an insulated, conditioned mech. room is your best bet, that should have been done before the furnace install, I'm suprised the builder did'nt know this.