High Efficiency and Combustion Air from Inside...thoughts

[jar546]

From what I understand, the manufacturer's do not consider this a HE furnace anymore.

 

[jar546]

Oh yeah, and the receptacle is not TR or GFCI like it is required to be and NO it was not part of the furnace assembly, it was put there by the installer

 

[globe trekker]

jar,

Is this installation the way the manufacturer requires it? Shouldn't both pvc pipes extend

to the exterior?

 

[Gregg Harris]

From what I understand, the manufacturer's do not consider this a HE furnace anymore.

Still listed and labeled as high efficiency installed as a single pipe or dual.

 

[Gregg Harris]

Also look at NEC 422-12 Central heating equipment under exception #1 if the receptacle is part of the individual branch circuit does not require it to be GFI

 

[jar546]

Also look at NEC 422-12 Central heating equipment under exception #1 if the receptacle is part of the individual branch circuit does not require it to be GFI

Don't see that. What year? Certainly not 2008

 

[jar546]

And certainly not 2011 NEC

 

[jar546]

Also look at NEC 422-12 Central heating equipment under exception #1 if the receptacle is part of the individual branch circuit does not require it to be GFI

Nor 2005, 2008, 2011 NEC

 

[jar546]

Please stop me!

Not in 1993, 1996, 1999, 2002, 2005, 2008, 2011

 

[Doorman]

Well, how about ’49, ’50, ’51, ’52, ’53, ’54, ’55, ’56, ’57, ’58′ 59′? Or maybe ’60, ’61, ’62, ’63, ’64, '65, '66, ’67, ’68, ’69, ’70 ...

With apologies to Johnny Cash.

 

[jar546]

Well, how about ’49, ’50, ’51, ’52, ’53, ’54, ’55, ’56, ’57, ’58′ 59′? Or maybe ’60, ’61, ’62, ’63, ’64, '65, '66, ’67, ’68, ’69, ’70 ...With apologies to Johnny Cash.

I went back to 48. Not kidding

 

[Papio Bldg Dept]

Well, how about ’49, ’50, ’51, ’52, ’53, ’54, ’55, ’56, ’57, ’58′ 59′? Or maybe ’60, ’61, ’62, ’63, ’64, '65, '66, ’67, ’68, ’69, ’70 ...With apologies to Johnny Cash.

was that a JC's reference for "one code at a time?"

 

[Francis Vineyard]

It's gets confusing to remember it all with every code change cycle and even more so if a locality is enforcing one version of NEC and a different year of IRC.

The 2011 added exceptions for the TR and the 2005 had an exception for GFCI:

2001 NEC



406.12 Tamper-Resistant Receptacles for Dwelling Units.

In all areas specified in 210.52, all nonlocking-type 125-volt, 15- and 20-ampere receptacles shall be listed tamper-resistant receptacles.

Exception: Receptacles in the following locations shall not be required to be tamper-resistant:

Changed From 2008

• 406.12 & Exception: Revised to specify that the requirement applies to “nonlocking” type receptacles and to add a new exception providing specific conditions under which receptacles are not required to be tamper-resistant

(1) Receptacles located more than 1.7 m (5½ ft) above the floor.

(2) Receptacles that are part of a luminaire or appliance.

(3) A single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

(4) Nongrounding receptacles used for replacements as permitted in 406.4(D)(2)(a).



2005 NEC

210.8 Ground-Fault Circuit-Interrupter Protection for Personnel FPN: See 215.9 for ground-fault circuit-interrupter protection for personnel on feeders.

(A) Dwelling Units All 125-volt, single-phase, 15- and 20-ampere receptacles installed in the locations specified in (1) through (8) shall have ground-fault circuit-interrupter protection for personnel.

(1) Bathrooms

(2) Garages, and also accessory buildings that have a floor located at or below grade level not intended as habitable rooms and limited to storage areas, work areas, and areas of similar use

Exception No. 1 to (2): Receptacles that are not readily accessible.

Exception No. 2 to (2): A single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Receptacles installed under the exceptions to 210.8(A)(2) shall not be considered as meeting the requirements of 210.52(G).

(3) Outdoors

Exception to (3): Receptacles that are not readily accessible and are supplied by a dedicated branch circuit for electric snow-melting or deicing equipment shall be permitted to be installed in accordance with 426.28.

(4) Crawl spaces — at or below grade level

(5) Unfinished basements — for purposes of this section, unfinished basements are defined as portions or areas of the basement not intended as habitable rooms and limited to storage areas, work areas, and the like

Exception No. 1 to (5): Receptacles that are not readily accessible.

Exception No. 2 to (5): A single receptacle or a duplex receptacle for two appliances located within dedicated space for each appliance that, in normal use, is not easily moved from one place to another and that is cord-and-plug connected in accordance with 400.7(A)(6), (A)(7), or (A)(8).

Exception No. 3 to (5): A receptacle supplying only a permanently installed fire alarm or burglar alarm system shall not be required to have ground-fault circuit-interrupter protection.

Receptacles installed under the exceptions to 210.8(A)(5) shall not be considered as meeting the requirements of 210.52(G).

(6) Kitchens — where the receptacles are installed to serve the countertop surfaces

(7) Laundry, utility, and wet bar sinks — where the receptacles are installed within 1.8 m (6 ft) of the outside edge of the sink

Changed From 2002

• 210.8(A)(7): Revised to add laundry and utility sinks to the GFCI requirement.



Francis

 

[north star]

= = =

Papio,

Here's a link to Johnny's song... "One Piece At A Time" song

[ the consecutive, muti-year variety ]

http://www.opel-p1.nl/onepieceatatime/index.htm

= = =

 

[MikeC]

While I know nothing of electrical requirements, being a "direct vent appliance", combustion air shall be provided per the manufacturer's instructions (IRC G2407.1). In this case, the unit appears to be a Trane XB90. Installation instructions do allow for indoor combustion are to be used as long as the criteria is met. One of those criteria being 50 cubic ft per 1000 btu.

You will find that quite a few of these high efficiency appliances allow for the use of indoor combustion air. It is still a high efficiency appliance, but the potential need for make up air to come from the outside may offset the high efficiency of the unit. In some cases, manufacturer's will send you back to the "local codes" if indoor combustion air is used. This really screws things up because it is a direct vent appliance and the code says to follow the manufacturer's instructions.

 

[Papio Bldg Dept]

= = =Papio,

Here's a link to Johnny's song... "One Piece At A Time" song

[ the consecutive, muti-year variety ]

http://www.opel-p1.nl/onepieceatatime/index.htm

= = =

One of my all time JC favorites...thx north star!

 

[Paul Sweet]

The high efficiency furnaces I'm familiar with require both pipes to terminate outside and within a foot or two of each other. This is so wind gusts don't create unequal pressures that might trip a safety switch and shut the furnace down.

 

[ICE]

The high efficiency furnaces I'm familiar with require both pipes to terminate outside and within a foot or two of each other. This is so wind gusts don't create unequal pressures that might trip a safety switch and shut the furnace down.

Some but not all.

http://www.inspectpa.com/forum/showthread.php?5619-Combustion-air&highlight=pressure+zone

 

[Daddy-0-]

You can take combustion air from indoors if the room is large enough. This makes it a "non direct vent" appliance and changes the vent pipe clearances. Look for the non direct vent charts in the installation instructions.

Love me some Johnnie Cash too. "Life ain't easy for a boy named Sue."

 

[MikeC]

I can only echo what Daddy-O- posted. This is a catagory IV appliance regardless of where the combustion air comes from. The fuel gas code is quite clear that it is to be installed per manufacturer's installation instructions. In this case (for this individual appliance), so long as you don't encounter one of the requirements mandating outdoor combustion air, indoor air is okay. It still allows for low temp venting through PVC or ABS. The only difference I see between the indoor vs. outdoor is the maximum vent length. Any time you encounter a catagory IV appliance, be sure to open the manual that should be attached to the appliance. This is where you will find all of the information you need.

 

[TheCommish]

regardless of the code(s) requiremnts, it seem to me that taking combustion air from the inside of the house and exausing it to the outside is a waste of energy, could cause back drafting of other apliances or problems with the combustion appliance if another exauste fan pulls the air out ot the space such as a jenaire grill or some of the monstorh ove the cook top fans I have seen.

 

[Francis Vineyard]

Commish I agree with your sentiments and MikeC's

A leaky or drafty house may use more fuel to heat the home but it will not make the furnace less efficient; it still consumes less fuel per BTU’s.



The appliance efficiency doesn’t change because of where the combustion air originates. The real value in efficiency is based on annual energy consumption. In a perfect Energy Star home would be constructed air tight; all gas fired appliances would be direct vented and a high efficiency mechanical ventilation (ERV OR HRV) exchanges and provides fresh make up air.

Francis

 

[Gregg Harris]

Other major issues that effect the efficiency of the HVAC system is that the airflow is rarely checked in heating or cooling. The gas pressure is rarely checked, and less than 5% of all gas appliances are set up with a combustion analyzer to adjust the combustion process of the appliance.

 

[Keystone]

Expanding on JAR's example, with the furnace being assumed as installed within a basement would the basement now be considered a plenum?

IPC 502.2 Rooms used as a plenum.

Water heaters using solid, liquid or gas fuel shall not be installed in a room containing air-handling machinery when such room is used as a plenum.