thetankatwaterheaterrescue.com Home 
Home Search search Menu menu Not logged in - Login | Register
thetankatwaterheaterrescue.com > Forums > The Tank > Water Heater Closet Door

 Moderated by: Admin
New Topic Reply Printer Friendly
Water Heater Closet Door  Rate Topic 
AuthorPost
 Posted: Sat Mar 10th, 2018 04:51 pm
  PM Quote Reply
1st Post
MarkH
Member
 

Joined: Sat Mar 10th, 2018
Location:  
Posts: 9
Status: 
Offline
My ~60 year old home has a dedicated water heater closet with an exterior door. The original door was hollow core without vents and was replaced when the luan sheeting began to deteriorate. It has been replaced twice now with hollow core doors that had vents pre-cut in them. It is due for another replacement and I have bought a solid core door so that I can finally put this job to rest. The question is, "Do I need to add vent(s) to the door?"

The original sill plate at the bottom of the door is a two-by-four with 3/4 inch holes running through it, the closet ceiling vents into the attic, and there is a flue above the heater that vents out through the roof. This is a single story home in Southern California. Wondering how much the building code may have changed in this regard, or if the original measures taken when the house was built still suffice. Thank you for your expertise.


Back To Top PM Quote Reply  

 Posted: Sat Mar 10th, 2018 09:42 pm
  PM Quote Reply
2nd Post
elenano
Member


Joined: Sat Sep 11th, 2004
Location: USA
Posts: 3943
Status: 
Offline
I think you you're going to need those vents, but I don't remember the formula for determining how many square inches they need to be. Likely someone else posting here can be more specific. If there is not enough combustion air, the heater will soot up and create a fire hazard. I doubt the holes in the sill are even close to enough.

Randy Schuyler

Back To Top PM Quote Reply

 Posted: Sun Mar 11th, 2018 12:49 am
  PM Quote Reply
3rd Post
eleent
Member


Joined: Sat Sep 11th, 2004
Location:  
Posts: 4231
Status: 
Offline
Hello,  The rule of thumb is one square inch of free vent space per 1000 BTUs. Your heater may be 30,000 or 35.000 BTUs.  What I just found, looking this up is code wants two vents, each within a foot of the top and bottom of the door.  They also want 100 square inches at each... which seems generous to me.  You might want to look up "combustion air" under whatever code you use and see what it says. :cool:

Yours,  Larry

Back To Top PM Quote Reply  

 Posted: Mon Mar 12th, 2018 06:11 am
  PM Quote Reply
4th Post
MarkH
Member
 

Joined: Sat Mar 10th, 2018
Location:  
Posts: 9
Status: 
Offline
Hi guys,

Thank you for your direction. I will track down my code and see what it says.

Regards,

Mark Harrison

Back To Top PM Quote Reply

 Posted: Mon Jan 13th, 2020 11:54 pm
  PM Quote Reply
5th Post
MarkH
Member
 

Joined: Sat Mar 10th, 2018
Location:  
Posts: 9
Status: 
Offline
Hi guys,

Sorry for taking so long to reply, but the project got tabled for a while. I finally installed the door without vents based on this information:

2018 International Residential Code
CHAPTER 24 FUEL GAS
Second Printing: Nov 2018

G2407.6.2 (304.6.2) One-permanent-opening method.
One permanent opening, commencing within 12 inches (305 mm) of the top of the enclosure, shall be provided. The appliance shall have clearances of not less than 1 inch (25 mm) from the sides and back and 6 inches (152 mm) from the front of the appliance. The opening shall directly communicate with the outdoors or through a vertical or horizontal duct to the outdoors, or spaces that freely communicate with the outdoors (see Figure G2407.6.2) and shall have a minimum free area of 1 square inch per 3,000 Btu/h (734 mm2/kW) of the total input rating of all appliances located in the enclosure and not less than the sum of the areas of all vent connectors in the space.


In my case, these were the calculations for the Water Heater:
Minimum free area = 40,000 BTU/HR x 1 sq. in. / 3000 BTU/HR = 13.333 Square Inches

I have two Water Closet Ceiling vents
Each vent is 5" x 13 3/4" which equals 68.75 Square Inches per vent
Total = 137.5 Square Inches

This looked to me to be 10 times larger than required so I did not vent the door. If I am missing something here, please let me know.

When I called the Los Angeles County Building & Safety Division, they said that they used the California Code, but also said that the manufacturer manual was a valid source for the information. I did confirm that this method is included in my manual.

Regards,

Mark Harrison

Attachment: One-Permanent-Opening-90k.png (Downloaded 4 times)

Last edited on Tue Jan 14th, 2020 04:31 pm by MarkH

Back To Top PM Quote Reply  

Current time is 11:54 pm  
thetankatwaterheaterrescue.com > Forums > The Tank > Water Heater Closet Door Top




UltraBB 1.17 Copyright © 2007-2008 Data 1 Systems