What is the difference between a manufactured/mobile home water heater and a regular water heater?

Friday, June 29, 2018

Every major water heater manufacturer has models of water heaters specifically designed for mobile homes. State Water Heaters, for example, has the “Scout” line approved for mobile homes. Water heaters that meet HUD standards have the following characteristics:

  1. Usually side plumbed for cold water inlet.
  2. Approved by a major national rating agency as compliant with HUD standards for energy efficiency. To avoid the possibility of carbon monoxide leakage into a mobile home when a gas water heater is installed, there must be a complete separation of the combustion system from the interior air of the home. This can be achieved by a “direct vent” sealed combustion system (although not all direct vent water heaters are HUD-approved) or by installing the water heater in a compartment that is sealed-off from the living area of the home and only accessible from outside.
  3. Must have a non-adjustable temperature and pressure relief (TPR) valve.
  4. A corrosion resistant catch pan and drain to the exterior necessary under the water heater.
  5. Water heater required to be secured in place, usually by a strap system.

    Only water heaters that meet the published standards of the U.S. Department of Housing and Urban Development (HUD) under Title 24 CFR Part 3280, “Manufactured Home Construction and Safety Standards,” are allowed by HUD to be installed in new mobile homes. Water heaters that are not HUD-approved are often marked as such on the side of the tank by the manufacturer, like in the photo above, taken from the side of a standard Rheem residential gas water heater. Also, all water heaters that are approved for mobile homes will have sticker like the one below, on the side of a Bradford-White.

    After a mobile home leaves the factory and is installed at a site, it is no longer under the oversight of HUD. So, theoretically, you could install a non-approved water heater when the time comes for replacement. Some local jurisdictions check for HUD approval and others don’t. But what happens if the water heater causes an insurance claim? Will your homeowner’s insurance honor the claim if the damage was caused by a non-approved appliance? Also, will a home inspector like us call out the lack of HUD-approval for your replacement water heater when you sell the home? For these reasons, we recommend a HUD-approved replacement water heater. They are more expensive than a standard water heater, but a good way to avoid future grief.

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Here’s links to a collection of more blog posts about WATER HEATERS:

Are water heaters required to be raised off the floor? 

Can a Temperature and Pressure Relief (TPR or T&P) valve be mounted to discharge horizontally?

Where are gas water heaters not allowed to be installed?  

Is the minimum size water heater inlet pipe 1/2" or 3/4" according to the building code? 

Can you use a light switch for a water heater disconnect? 

How can I tell if a water heater is HUD-approved for mobile/manufactured homes?

Can you wire a 240-volt water heater with 120 volts? 

Is it alright to have a shut-off valve on both the hot and cold water pipes at a water heater?  

What is the minimum clearance to doors and windows for an outdoor tankless gas water heater? 

What is required clearance for access and working space in front of an electric water heater? 

Why is the water heater older than the house? 

Does a water heater need a shut-off valve? 

Why should a tankless water heater have an isolator/service valve kit installed?

When was a gas water heater first required to be elevated 18 inches above a garage floor?  

Can the temperature and pressure relief (TPR) valve discharge pipe for a mobile/manufactured home water heater terminate under the home? 

What is the purpose of a thermostatic mixing valve above a water heater? 

Does a tankless gas water heater still work with no electricity during a power outage?  

•  Why do water heaters have a sacrificial anode? 

Does a tankless water heater require a pressure relief valve?

When is a water heater drain pan required?

Why is there water in my water heater drain pan?

What does it mean when a water heater Temperature/Pressure Relief (TPR) discharge pipe is "trapped"? 

Can I leave a gas water heater in place when remodeling a garage into a family room or bedroom? 

Where do I find the water heater in a mobile home?

Does a tankless water heater in an attic require a drain pan? 

Does an electric water heater require a disconnect? 

Is a catch pan and drain piping required for a replacement water heater?

What is the difference between a single element and dual element electric water heater? 

What is an FVIR water heater?

What is a heat pump water heater?

What is a dielectric union?

What's that powdery crust on the pipe connections at the water heater? 

What are the most common installation mistakes with water heater replacement?

Why is my water heater making strange (rumbling, gurgling, knocking or banging) noises? 

What can I do to make my water heater last longer?

How can I determine the age of a water heater if the serial number is missing or decoding it is impossible? 

How does a hydronic heating system work?

What is the difference between a regular water heater and a direct vent water heater? 

What is the difference berween a regular water heater and a power vent water heater?

What is backdrafting at a gas water heater? 

How do I determine if a water heater is gas or electric?

What does it mean when a gas appliance (water heater, furnace, or range) has been "red tagged"?  

• What's the valve with the flip-up handle on the water heater for?

• Why is an older water heater an insurance problem?

    Visit our MOBILE HOMES and WATER HEATERS pages for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.

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