Mobile home heating systems:

How to Inspect the heating systems in mobile homes, trailers, double-wides, multi-wides:

How to spot common and dangerous defects in heating equipment incuding furnaces and boilers, inadequate heat distribution, freeze-ups, and safety hazards. Mobile home or manufactured home heating ductwork defects. Mobile home insulation defects and remedies to reduce heating costs.

How to save heating costs for mobile homes and trailers or multi-wides. Page top sketch was provided courtesy of Carson Dunlop Associates, a Toronto engineering, education, and home inspection company.

Manufactured Home & Mobile Home Heating System Problems

General Characteristics:

• Hot air, gas-fired, central return heating units are most common ; oil & electric mobile home furnace-heaters are also used;
• 20% of mobile homes have problems with HVAC (C. r. survey);
• MANUFACTURED & MOBILE HOME HEATING STANDARDS & CODES

[Click to enlarge any image]

Question: I was startled out of my skin to see a cat jump into the living room from a floor vent

(Aug 29, 2012) Maxine Payne said:

The red tag was apparently covered up when vinyl siding was installed. Now I want to sell the property, but I can't because I do not have the red tag number. How do I get the red tag number?

(Aug 29, 2012) Greg Filian said:

The flashing of the lights mentioned are they in the whole house or just one outlet? If it's just one outlet it may be just the outlet, if it's the whole house the problem may be at the main connection.

(Sept 8, 2012) Gail said:

I am looking at buying a double wide through an estate sale. The "trustee" of the estate is the deceased owners daughter, who know very little to anything about mobile homes (as I).

I am hiring an inspector, how ever he wont be available for 3 weeks and I have an immediate concern...

While standing in the living room I was startled out of my skin to see a cat jump into the living room from a floor vent ( vent cover was pulled off) I looked into the vent and it appears to be completley open - no duct work - just a view of the ground beneath.

The daughter said that that was common and is there for ventilation. LOL Tell me this isnt so!

Reply:

Gail,
Thank you SO much for the wonderful cat - HVAC system question.

Yes I can tell you "it isn't so" - that is, it is not good practice to simply leave floor vents in a home open to the outdoors such that anything, including a cat (or worse, a raccoon) can hop in for a visit.

I can imagine a few reasons why you might have found the missing duct work and open floor vent, all adding up to some more trouble and work for you. For example most likely there was a heating or heating and cooling system that used air but that has disintegrated, been damaged, fallen off, or was simply removed and abandoned.

Sometimes too, when warm or cool air delivery into a home is poor in flow rate or quantity, people try to improve system operation by adding more return air to the system by just cutting an opening that lets outdoor air into the system somewhere.

The problem is this is the most expensive possible way to heat or cool a home since it's a "one way" design - we take un-conditioned air from outside, heat it or cool it, then try moving it into the living area.

Really the most significant implication of the cat in the hat, I mean cat in the vent discovery in your possible future home's heating sysem is that it's a red flag to watch out for other work done or "problems solved" by the same person on that home - as you may find other amateur workmanship that lengthens the list of repairs and improvements needed to make the home safe and habitable to normal standards.

Keep me posted, and send along photos if you can (use the CONTACT US link at page bottom or top) - especially if ... the cat comes back.

Daniel Friedman

I suppose a less ridiculous explanation that the owner could have invented might have been to explain

"Oh I forgot to tell you, that's just Marion, my mom's cat. Marion comes with the house. The hole in the floor is her pet door."

Checklist of Common Defects in Mobile Home & Manufactured Home Heating Systems

• Air filters are often ignored - change the filter monthly when the heating or cooling system are in use. A clogged air filter will reduce air flow from your heater, increasing heating costs as well as making the home less comfortable.
• Combustion air defects - such as inadequate combustion air can cause unsafe operation and risk fatal carbon monoxide poisoning.
  
  See MANUFACTURED HOME HEATER COMBUSTION AIR DEFECTS below on this page
• Furnace cycles on and off during heating cycle:
  
  see FURNACE FAN CYCLES DURING HEAT for a diagnostic guide & suggested repairs.
• Fuel connection should have label indicating equipment and piping are ok for natural or LP gas or both
• Inadequate clearance to combustibles modified equipment, controls, flue-vent connectors, burners, duct work, venting
• Outside heating oil tank not protected from freezing (using more expensive kerosene mix?) or use of heating tapes on heating oil lines - a possible fire risk (photo above)
  
  See ABOVE GROUND OUTDOOR OIL TANKS
  
  and at MOBILE HOME FIRE SAFETY

• Oversized or under-sized heater for the mobile home - if the mobile home furnace BTUh rating is more than 120% of the proper size for the home the system may be both inefficient and dangerous and due to short-cycling at the furnace, also uncomfortable for building occupants.
  
  See details at FURNACE OVERSIZE PROBLEMS
• Underground oil storage tank (UST) or above ground oil storage tank (AST) leaks: a home owner is generally responsible for the reporting and clean-up costs if an oil storage tank leaks.
  
  These costs can be very high, even disastrous. At a mobile home park some case law suggests that for permanently-installed utilities the mobile home park owner is responsible for those services and that equipment.
  
  See OIL TANK, BURIED, ADVICE
  
  Even for above ground oil storage tanks, the mobile home park owner may be held responsible for that equipment as often laws distinguish between the mobile home and utilities provided "up to the point of connection to the home".
  
  See ABOVE GROUND OUTDOOR OIL TANKS
  
  And see OIL TANK LEAKS & SMELLS - home
  
  Watch out: be sure that the ownership and responsibility for oil storage tanks at a mobile home is given clearly and that the home complies with the park rules and regulations.
  
  See MOBILE HOME OIL TANKS for details
• Unsafe heating system chimney and vent installations on mobile homes and trailers (photos above)
  • Our photo above shows an oil fired heating flue venting directly through the mobile home side wall and just inches from the home's windows.
  • Our photo below shows a makeshift gas flue using aluminum venting (not recommended, unsafe), a too-short chimney (inadequate draft) and flimsy construction, as well as probably leaks into the home wall over the entry door. Notice the soot around the base of the flue where it penetrates the wall?

• Unsafe fire clearances and inadequate working space to maintain heating equipment are not due to the mobile home manufacturer but due to low-budget modifications such as this oil burner access through a bath vanity cabinet door (photo above).

• Warm air heat return air in a mobile home: all return air taken from crawl area beneath living unit - one-way heat; blocked return; blocked supply; ducts through un-heated area;
  
  NO return air, or none when utility closet door is shut! We see this design too often - it is the most expensive way you could heat your mobile home since none of the interior air is being recycled through the heating furnace.
  
  Mobile home heat safety warning: Our photo of a mobile home warm air furnace (left) shows that someone has put paneling over the door to stop drafts - also cutting off return air to the furnace and possibly making it very dangerous if this step has also cut off combustion air from this heater.
  
  Because the mobile home furnace is shoe-horned into a tight space it is too often the case that the system is not inspected and cleaned on schedule. Generally you will save more on reduced heating costs by having an expert clean and tune the system than you will pay for the service call.

• LP Tanks, copper gas lines are often left unsupported and exposed to mechanical damage; also check for LP gas leaks at tanks or fittings;
• Oil tanks at trailers and mobile homes - indoor-rated heating oil tanks are quite often placed outside, above ground, in ground contact, with heat tapes (a fire hazard), often leaking, and in cold climates, exposed to frost-risk which in turn risks loss of heat and related damage to the home
• Missing or still-covered-over spark arrestor on the heating flue on a mobile home - have your heating service technician check the safety of the entire flue and chimney, including the outside components

Combustion Air Defects & Safety Hazards at Doublewide, Mobile Home or Trailer Home Heating System

Below our photographs illustrate several unsafe conditions at a house trailer's heating system inspected by D Friedman & S Vermilye during a mobile home site safety investigation.

...

• No return air from occupied space to the furnace: Above we notice that when the door to the "furnace closet" in this mobile home is shut, there is no return air movement from the home's heated interior to the furnace - creating the most-expensive possible way to operate the furnace. We call this a "one way" heating system: scrounge some air from a cold outdoor or crawl space source, heat it, and blow it into the living space.

In addition to the absence of return air to the heating furnace we notice that

• Dirt blockage of air flow: the return air inlet grille is partly blocked by dust and debris, further reducing air flow, increasing heating cost, and ...
• Watch out: there is an increased risk of potentially fatal carbon monoxide poisoning if the system lacks adequate combustion air
  
  
• Blocked air filter: if an air filter is installed (remains to be discovered), given how dirty is the exterior of this furnace the air filter may be equally dirty and airflow blocked
• The leak stains and corrosoion on and below the heating flue indicate that the chimney and flue are leaking, risking hidden damage, leaks, holes, water or rust damage to the furnace heat exchanger: all further pointers to an unsafe heating system
  
• Source of combustion air: On some mobile home heater installations combustion air is provided from outdoors through wall or floor openings in the furnace closet, increasing safety but, depending on system design, ignoring operating cost
• Unsafe chimney outside: incomplete, leaks, missing cap, too short, bad draft - are illustrated by our outdoor heating flue/chimney photos earlier on this page.

See details at COMBUSTION AIR SAFETY in MOBILE HOMES

Manufactured & Mobile Home Heating Standards & Codes

Full text of the manufactured and mobile home heating standards can be found in

PART 3280—MANUFACTURED HOME CONSTRUCTION AND SAFETY STANDARDS [PDF] newer copy retrieved 2017/07/13 - faster-loading

See Subpart H, Heating, Cooling and Fuel Burning Systems in that document.

Ver5 - 2018 01 13 updated through January 2018 - Steve Vermilye, New Paltz NY and Daniel Friedman, Poughkeepsie NY, Hudson Valley ASHI Chapter Seminar, Newburgh NY, January 4, 2000, NY Metro ASHI Fall 99 Seminar, Holiday Inn Crowne Plaza, White Plains NY, October 2, 1999.

Mobile Home & Trailer Home Insulation & Ventilation Defects, Diagnosis, Repair, Improvement

This topic has moved to a separate article at MOBILE HOME INSULATION & VENTILATION

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Reader Q&A - also see RECOMMENDED ARTICLES & FAQs

On 2020-09-24 by Anonymous

Re-posting from private email:

Hi I had insulation blown in under a mobile home. There is an old bladder that they patched using only staples and left other holes open.

The ductwork is old and by all accounts it seems that there are holes and or disconnects. (excessive dust, some rooms barely cool, high energy bills, rusted out holes in bottom of vents and small holes 1/2 can be seen)

Since they have blown insulation in I have had a fine white dust all over the home. There was also a big hole not sealed near HVAC system and about an inch of blown in insulation surrounded it. What can I do to fix the duct work now that it has been encased in insulation. Why would they blow insulation in over old duct work that was obviously faulty?

Can the force of insulation do anything to pipes, we have had to fix leaks. Or obstruct duct work, the air flow was considerable lessened between the time before and after they blew it in.


Moderator reply:

Sounds as if you need to ask your contractor or a handyman to find and fix the ductwork opening and then HEPA-vac to clean up all that dust.

If there are rusted-through or other openings and bad leaks in your duct system, a savvy contractor might have seen that and should have warned you to replace the ductwork first.

Why wouldn't a contractor say so? Pressure to bid low and get the job?

Why would they blow insulation that leaks into the home? Maybe having to work in cramped quarters where it's hard to see, perhaps by under-paid or hasty workers, rushing, or an under-bid job, or simply human error.

On 2020-02-25 - by (mod) - how many air vents are needed on a hot water heating system and where should they be placed?

Thanks for a great question, Tony: how many air vents are needed on a hot water heating system and where should they be placed.

Regrettably there's no single absolutely-right answer, because each home may vary in the routing of hot water heating piping as well as other details like type of heat radiating devices and their location that make air bound heating pipes more or less-likely.

But I'd say we want at least two air vents:

1. a float type air vent located at a high point above the heating boiler where hot water exits the boiler and enters the heating zone loop(s). The usual place for that is atop the air separator or air scoop found above the boiler on the heating outlet pipes.

2. a manually-operated air vent at the far end and highest point of each heating zone loop.

In addition we might need to add

3. a manually operated air vent at the end or high point of any heating piping loops that loop up, across, then back down through the floor, as we may find air trapped in such "upside down "U" shaped runs.

Please see details at AIR BLEED VALVE INSTALLATION

where I will repeat your question so as to invite comment from other readers or experts.

On 2020-02-25 by Tony Edwards

How many air vent do i need for 14x70 mobile, and where do you need to place them

On 2019-11-09 - by (mod) -

Lewis

My goodness, that's a completely terrible looking furnace.

Watch out: Between the rust and the mold and the debris around it it and missing parts it couldn't possibly work and even if it turned on it doesn't seem to be in any respect safe.

On 2019-11-09 by Lewis Rockwell

Wont heat

On 2019-10-03 - by (mod) -

Sounds as if your heating system has lost electrical power. Check starting at the main fuse or breaker panel.

On 2019-10-01 by Jerry

1978 HOME furnace has no spark, or fuel going into the regulator in mobile home.

On 2019-09-11 by (mod) - rats get into bedroom through furnace ducts

No I doubt that that's OK -
Rats themselves are a health and safety hazard and need to be exterminated and cleaned-up and the cause of their infestation corrected; any damage ought to be repaired.

When you cover up some part of a gas heating system (whose details I don't know and can't know by just e-text) I worry that you've messed up combustion air (potentially fatal) supply to the burner, or messed up supply or return air (that mean parts of your home are un-heated and could risk frozen pipe damage)

On 2019-09-10 by kathy shepstone

I have single wide moblehome the gas furnace sits in living room rats have torn up duct to bedroom so I cover it up at bottom of furnace so it just blows into living room is that ok

On 2019-08-20 - by (mod) -

Tim:

Sorry but there's not one "right" answer;

You're asking about the air filter for a heating or air conditioning system in a doublewide home.

Typically the air filter is at a single return air inlet grille; sometimes the air filter is installed in a rack right inside the air handler.

See details at AIR FILTER LOCATION

On 2019-08-20 by Tim smith

Where does the filter go in a 96 doublewide? Also when the air is ran it doese not get cool much. And last some one cut a section ofthe main trunk off i taped it up for now will that have an afect on cooling?

On 2017-02-03 by (mod) - Cut a hole in the floor next to your forced air heater? Safety worries.

Watch out: If you are describing a manufactured or mobile home or doublewide home that has its heater in a "closet" and the closet is getting very hot, it's possible that the heater, probably a furnace is not running properly.

The risk is a fire or even fatal carbon monoxide poisoning.

Get a heating service tech to inspect the heating system including its proper and safe operation, right away.

And your dad should not go to sleep tonight before making double sure that there are properly-installed, tested, working smoke detectors and carbon monoxide CO detectors in his home.

On 2017-02-03 by John - Is it safe to cut a hole in the floor next to your forced air heater?

my dad said the closed the heater is in gets too hot even though it has doors that vent the heat which he insists leaving open all the time blocking the hallway.

Also he has cut a hole in the floor down to under the crawl space under the house.

Is it safe to cut a hole in the floor next to your forced air heater, exposing the air under your house to the inside of your house, and using the air under your house to circulate through out your house, by sending it through your heating system

Question: Mobile home furnace not working

(Dec 14, 2012) Sean Newcomer said:

I have a brand new thermo pride furnace for my moble home it ran fine for two months the furnace started cylcling, it would burn then the fan would come on after a couple minutes the call to burn would shut off, then the fan would shut off a few mins later, upon fan going off the burner would cycle for heat again and the fan would come on heat would stop and so on. But the heat keeps climbing it doesn't stop

so i got ahold of the installer he told me it was the thermostat, i replaced it and still does the same its under warranty but i can't afford to pay a serve man 200.00 to come to tell me the problem. is it the burner control or is it the computer board can it be reset and how

Reply: the heat keeps climbing it doesn't stop

Sean,

IF the warm air output from a supply register is blowing right onto the room wall thermostat, then "the thermostat is the problem" could be a correct statement.

Otherwise I suspect a bad fan limit switch or improper installation of that control. For example, if the limit switch is mis-adjusted or if its sensor spring is binding, the system won't work properly.

Watch out:  a fan limit switch that is bent, damaged, mis-handled, even mis-adjusted, can be dangerous, risking damage to the heating equipment or even a fire.

Diagnostic articles for heating problem troubleshooting are at

• DIAGNOSTIC GUIDE A/C or HEAT PUMP
• DIAGNOSTIC DETAILS A/C or HEAT PUMP
• DIAGNOSE & FIX HEATING PROBLEMS-FURNACE

 

Question: fixing or replacing mobile home or doublewide ductwork invaded by rats

23 January 2015 Chuck said:

I have a doublewide mobile home with the air ducts in the cieling. A rat has gotten into the air duct and chewed insulation and now insulation is blowing through the vent. I am going to have a company put a camera up there to find the break so it can be fixed.

My question is would it be easier for me once I knew exactly where the break was to just go in from the roof. It seems alot faster and less expensive than tearing out the cieling and replacing sheetrock, tape and bed and repainting, not to mention the mess in the house. What are your thoughts?

Reply:

Chuck,

If your doublewide has a conventional continuous metal roof over an inaccessible space then you won't do well trying to cut into the roof and you risk creating a point of future roof leaks. I'd be inclined to work from the interior. But then I haven't seen your home.

If there is an attic access (which some doublewides have) then of course it'd make sense to get into that space and remove and replace the ductwork and any contaminated insulation.

Further, if there were rats in the ductwork, you want to replace ALL of the ductwork and insulation where rats were nesting lest their pee and poop and other debris become a health concern later on.

...

Continue reading at COMBUSTION AIR SAFETY in MOBILE HOMES or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see MOBILE HOME HEATING REPAIR FAQs - questions & answers about troubleshooting the heating system in manufacatured homes, mobile homes, doublewides, trailers, campers

Or see these

Heating System Repair Articles

• BOILERS, HEATING - home - diagnose & repair hot water heat
• COMBUSTION AIR SAFETY in MOBILE HOMES
• DIAGNOSE & FIX FURNACE PROBLEMS list of things to check, step-by-step.
• FURNACES, HEATING - home - diagnose & repair forced warm air heat
• FURNACE OVERSIZE PROBLEMS
• HEAT WON'T TURN ON the heat won't turn on at all
• MOBILE HOME FIRE SAFETY
• MOBILE HOME INSULATION & VENTILATION to improve those systems
• MOBILE HOME OIL TANKS

Suggested citation for this web page

MOBILE HOME HEATING SYSTEMS at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to MANUFACTURED & MOBILE HOMES

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