# hwt's in mobile homes



## redbeardplumber (Dec 4, 2012)

like the cardboard box on a MI40 bradford white. "not to be used in mobile homes". 

what constitutes a mobile home? wheels? if its not on wheels and connected to a house is it a house? This is the situation I have. It is not in a closet. The tank by bradford white that is approved for mobile homes is twice the cost. What is the difference in the tanks?

thanks

Case


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## bambam (Mar 25, 2014)

For one I believe al BW Mobil home tanks are lp with conversion kit inside. Biggest difference is the air intake and venting. Inside tank installation should have 4" air inlet through the floor.


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## plbgbiz (Aug 27, 2010)

The differences have mostly to do with the vent and combustion air. You must use the vent kits designed for that application. Also the WH must be secured to the structure. Most mobile home WH's come with those parts. The venting is sold separately. 

State has an excellent drawing and install instructions on their website for manufactured home approved units.


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## Catlin987987 (Nov 12, 2010)

redbeardplumber said:


> like the cardboard box on a MI40 bradford white. "not to be used in mobile homes".
> 
> what constitutes a mobile home? wheels? if its not on wheels and connected to a house is it a house? This is the situation I have. It is not in a closet. The tank by bradford white that is approved for mobile homes is twice the cost. What is the difference in the tanks?
> 
> ...


I have seen many mobile homes with factory installed water heaters that the tank manufacture states they are not to be installed in mobile homes. I have seen them vented with regular Bvent and a combustion air. You would have to reinvent the wheel in order to convert it into a direct atmospheric vent.


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## jeffreyplumber (Dec 7, 2009)

I put many water heaters in mobile homes used regular residential30 gal that fit thesewere all on outside wall with openings for air in the door and standard b vents. I never did use a mobile home W/H on a mobile home. They were inspected by the Gas co. natural gas. Never a problem.


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## Redwood (Sep 8, 2008)

jeffreyplumber said:


> I put many water heaters in mobile homes used regular residential30 gal that fit thesewere all on outside wall with openings for air in the door and standard b vents. I never did use a mobile home W/H on a mobile home. They were inspected by the Gas co. natural gas. Never a problem.


Yea a lot of the time you can use the regular ones, but some tin houses on wheels don't have that vented panel or door and it comes through the floor in which case it take the special mobile home water heater...


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## plbgbiz (Aug 27, 2010)

I have seen many green tags on non-compliant jobs.


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## saysflushable (Jun 15, 2009)

I think it has more to do with being able to convert from natural to propane. I think if a home has axels gas convertion is required. Heck I wish they would just put electrics in, that would make life easier on the owners and cheaper


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## Best Darn Sewer (Dec 23, 2012)

redbeardplumber said:


> like the cardboard box on a MI40 bradford white. "not to be used in mobile homes".
> 
> what constitutes a mobile home? wheels? if its not on wheels and connected to a house is it a house? This is the situation I have. It is not in a closet. The tank by bradford white that is approved for mobile homes is twice the cost. What is the difference in the tanks?
> 
> ...


Like others have said, the vent is different because you have a vent inlet below the burner assembly and the top vent attaches directly to the flue lip instead of a draft divertor. The reason is because oftentimes the heater is installed behind a huge panel typically in a hallway or bedroom and according to IPC a gas fired water heater can't pull its combustion air from the same air a human will be living and breathing in, like a bedroom or bathroom, so they have to get their combustion air from the outside or from under the trailer. 

The reason the cost is so high is simple supply and demand because they don't sell or make nearly as many of that style as they do standard heaters thus manufacturung them and keeping them in stock costs more.


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## plbgbiz (Aug 27, 2010)

saysflushable said:


> I think it has more to do with being able to convert from natural to propane. I think if a home has axels gas convertion is required. Heck I wish they would just put electrics in, that would make life easier on the owners and cheaper


The gas valve conversion is a convenience. The venting is a building code issue.


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## ZL700 (Dec 8, 2009)

*^ Not Really*


Mobile home and manufactured homes are governed by HUD (US Department of Housing and Urban Development)

2 main items that affect water heaters, all gas appliances for that matter, one, it must be sealed combustion or have makeup air provisions. And the second requirement is that the unit must be field convertible capable to LP and back to Nat Gas, along with the requirement that the kits be provided and shipped with/inside the heater. Purpose being, when they install the heaters and ship the housing units, they don't know where they are going. 
Why this would affect the replacement market, I do not know but it falls under the same requirement. There are some other requirements such as combustibles, flame spread rating on enclosure, distance to sleeping, and more. 

One distinguishing difference and not always recognized by all AHJ's is the type of manufactured home (wheels or not). The ones placed on permanent foundations are often classified as permanent residential structures and that's why you see standard furnaces, boilers and water heaters installed. If these are shipped without the gas appliances they need not have to meet the HUD requirement.


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## saysflushable (Jun 15, 2009)

what about the unit Loews sells for mobile home's? It is gas convertible but not sealed combustion. at least it doesn't have the inlet port on the floor. I'm just glad I don't deal with it often. People have no money then they have a horrible expensive water heater to pay for.


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## ZL700 (Dec 8, 2009)

*Good question*

Installed in an outside closet or in a sealed vestibule accessed from outside requirements is how most skirt the sealed combustion/intake air/roof jack requirement.

Like I sort of mentioned earlier though "permanent structure" wording for HUD is where it gets vague. But inspectors often don't care about that.


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