flue length

[cbs]

I inspected a property with a 75,000 btu gas furnace today. The flue was over thirty feet in length. The slope for the majority of the run was aprox. 15 degrees. Is this acceptable? I have found no data on the manufacturers site.
Charlie in Brandon, MS

[karsthuntr]

We need you to post a little more info. Model and serial, 90 or 80 percent, what type vent material, etc...

[NormChris]

The only way to know is to consult the specific flue sizing charts from the manufacturer for that particular brand and model furnace. There is no other way to know exactly what is correct.

You should also know the different furnace classifications for flue types. There are different catagories of furnaces and their respective flues.

I take it you are a home inspector.

Norm

[cbs]

Sorry,
I did not find that data. Or rather do not know how to get that info from the data plate. It is part of a split system with a Rudd 3.5 ton HVAC side. It is about 18 mth old. Can you help?

[cbs]

B vent

[cbs]

Yes a home inspector

[cbs]

May I infer from the silence that my profession is not liked here?

[cbs]

Well gentlemen,
Can you give me any general guidelines to inspect by?

[jetstream]

Don't infer anything. Get the mfgr's installation requirements and it'll tell you what you need to know. Never mind general guidelines, you want specifications for that particular make and model.

[karsthuntr]

If you post model number we can tell you the guidelines.

[karsthuntr]

Model number will be under the header that says "model number" and read something like UGPL-07EYGBS

Serial nuber will be something like AN172 M3804 12345

[cbs]

Your points are well founded. I should have recorded that info in this case. One of the pitfalls of what I do is the time constraints placed on me. (No excuse for not recording the info to research this) We are trained to be a generalist- look for things that don't fit general guidelines and then call for review by a specialist. I believe I will call this for review. And lurk here on occasion.

Thank you.

[Edited by cbs on 03-12-2005 at 10:04 PM]

[docholiday]

Consult the national fuel gas code. Many mfg's dont publish 80% venting information because there is a higher authority. About time they print it the code can change. They do state that you should consult the national fule gas code for venting. All the mfg's tell you is what size pipe to run for a standard installation.

Off the top of my head, 30' horizontal is too long, the weight of the cool air alone n the pipe will prevent a draft from starting.

[cbs]

Thank You Doc!
This home has never been occupied so I found no signs of condensation on the pipe. You comment mirrors my concerns.
Have a blessed evening.

[steve3871m]

The only way to tell is to consult the GAMA tables. You can find these in any installation packet or the National fuel gas code. Last updated version (of the tables) was 1993, which will cover fan assisted as well.

30' length may or may not work. More probable on single appliance only (not vented with others category I equipment), however refer to the GAMA tables for the correct answer and hire an HVAC pro.

I've ran across far to many "home inspectors" that attempt to cross into uncharted territory and provide incorrect information.

Steve

[cbs]

" the correct answer and hire an HVAC pro. "

It is my job to figure out if one is needed NOT be one- It is impossiable to carry every set of codes and charts but rather use good judgement when calling for a "pro"

"I've ran across far to many "home inspectors" that attempt to cross into uncharted territory and provide incorrect information. "

I've run across many a jack leg hired by R/E agents to bless any thing- I believe I've called for a pro one this one since it seems to be a canadite for review. I will not call out a pro simply to cover my butt rather Just when it will protect my client.

Thank each one of you for your responses


[Edited by cbs on 03-13-2005 at 01:43 PM]