Forum Discussion

imjustdave's avatar
imjustdave
Explorer
Jun 29, 2020

Generator Sound/fire box

Installing a onan generator in a 5th wheel. My 5th wheel came without the fire bax - sound box, to make matters worse the local dealer isn't very helpful in getting the factory one. More like drama about it.

The other issue is I haven't been able to find a unit with a genst in it so i'm not entirely sure what all this box does - is.

Anyways hoping others could maybe send photos and tell me what they have in their trailers.

Just for clarity the ONAN is going in, that choice has already been mad and won't change. Other advice for portable, honda ETC isn't needed in this topic please, that isn't what this topic is about.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    The easiest way is to use a portable.. Or two
    Honda, Yamama and several other INVERTER generators you can get optional Parallel Kits. two Honda 2000i's (The i means inverter) give you a full 30 amps with the parallel kit or a 2000i and a 200i-companion (the companion is more expensive but the parallel kit is cheaper as part of it is built into the Companion) You can also use them independent.

    Honda's have the optional extended run tank as well Far as I know they are the only ones that have that feature.

    You can store 'em anywhere you can store 'em Just be sure to lock them down both in use and storage so they don't grow legs and walk off,
  • Different strokes for different folks. If someone gave me an Onan I would sell it. Others do not mind the expense or owning one. Box's for the gensets vary a bit but are basically a metal lined box.

    Soundproofing is not a consideration in the RV industry, until getting up in the high end coach's. The older Onans are horribly noisy and because the way they are added to the RV are difficult to quiet down. The new ones may be quieter?? but unlikely, as the only online statement I see is the new LP ones are 15% quieter than a diesel generator.

    You tube and the web will be your friend on this, there is lots of videos and info. Here is a sample. I use a window AC and a Honda 2000, not for everybody.

    https://www.youtube.com/watch?v=s39PJtgZ7HA
  • wa8yxm wrote:
    The easiest way is to use a portable.. Or two
    Honda, Yamama and several other INVERTER generators you can get optional Parallel Kits. two Honda 2000i's (The i means inverter) give you a full 30 amps with the parallel kit or a 2000i and a 200i-companion (the companion is more expensive but the parallel kit is cheaper as part of it is built into the Companion) You can also use them independent.

    Honda's have the optional extended run tank as well Far as I know they are the only ones that have that feature.

    You can store 'em anywhere you can store 'em Just be sure to lock them down both in use and storage so they don't grow legs and walk off,

    I don't think you understand on board gensets. They are all about convenient power. There are no gas cans to deal with. There is no set up. No cables. No storage or security issues. No carrying or handling.
    No walking off.
    There is just push button convenience. Want power just press a button and you can run both A/C units or anything else.
    Yes you pay for that convenience,however with a on board genset your RV is ALWAYS self contained.
    @ the OP my suggestion is contact a genset specialist or service company instead of an RV dealer.
  • X2 but in my shop is a generac rv gen set, in a box 30amp like new less than 5hrs, inlaw was redoing a rv and bought this died before install. if you have interest pm me or send a text # I, send pics , one nice self contained unit.
  • When I put an Onan in our fiver, that wasn't generator prepped here is what I did. First of all I'm glad it wasn't prepped. Later saw some of the same make fivers prepped, no thanks. I measured for the "firebox", and layed out what I wanted, then took the layout to a Sheetmetal shop. He did what I wanted, there were several pieces, sides and top. I brought it home and installed it. Has worked well for 17 years. Wasn't a hard job at all if you are handy.
  • The boxes? I have seen in my RVs, all class A's
    One Genirac the rest Onan were not for noise
    They provided heat/ protection for the RV from the generator, they also provided some measure of road grime protection, all had two openings on the bottom, fresh air in for cooling, hot engine fan air out
    As long as your box does that, that are good
  • YEARS ago when most Class C's had no Genset's we installed Gensets and had to build the box and insulate it and make it air tight to the Inside. You build a box in a RV to make it slightly less loud inside and to seal it from the inside. Look at the link I provided. This type material is usually available locally in 4 by 8 foot sheets. It has a foil back and you install with the foil visible. You cut and install on the sides and back and ceiling using liquid nails. If you have no box make one out of 3/8 plywood and then install that insulation. Once the Insulation is glued in you then use rubber silicone to seal all the edges to make it air tight. Most RV Gensets are vented thru the floors now and require no vented door. BUT, I would vent the door if on a 5th wheel or trailer. More air is good. Doug
  • dougrainer wrote:
    YEARS ago when most Class C's had no Genset's we installed Gensets and had to build the box and insulate it and make it air tight to the Inside. You build a box in a RV to make it slightly less loud inside and to seal it from the inside. Look at the link I provided. This type material is usually available locally in 4 by 8 foot sheets. It has a foil back and you install with the foil visible. You cut and install on the sides and back and ceiling using liquid nails. If you have no box make one out of 3/8 plywood and then install that insulation. Once the Insulation is glued in you then use rubber silicone to seal all the edges to make it air tight. Most RV Gensets are vented thru the floors now and require no vented door. BUT, I would vent the door if on a 5th wheel or trailer. More air is good. Doug


    Thanks Doug, But I think we missed your link?
  • wa8yxm wrote:
    The easiest way is to use a portable.. Or two
    Honda, Yamama and several other INVERTER generators you can get optional Parallel Kits. two Honda 2000i's (The i means inverter) give you a full 30 amps with the parallel kit or a 2000i and a 200i-companion (the companion is more expensive but the parallel kit is cheaper as part of it is built into the Companion) You can also use them independent.

    Honda's have the optional extended run tank as well Far as I know they are the only ones that have that feature.

    You can store 'em anywhere you can store 'em Just be sure to lock them down both in use and storage so they don't grow legs and walk off,


    Easier then pressing a button on the wall?
    I appreciate the suggestions but this topic is about that box. The decision of what system to go with has been made, right or wrong it has been made.
  • Lantley wrote:
    wa8yxm wrote:
    The easiest way is to use a portable.. Or two
    Honda, Yamama and several other INVERTER generators you can get optional Parallel Kits. two Honda 2000i's (The i means inverter) give you a full 30 amps with the parallel kit or a 2000i and a 200i-companion (the companion is more expensive but the parallel kit is cheaper as part of it is built into the Companion) You can also use them independent.

    Honda's have the optional extended run tank as well Far as I know they are the only ones that have that feature.

    You can store 'em anywhere you can store 'em Just be sure to lock them down both in use and storage so they don't grow legs and walk off,

    I don't think you understand on board gensets. They are all about convenient power. There are no gas cans to deal with. There is no set up. No cables. No storage or security issues. No carrying or handling.
    No walking off.
    There is just push button convenience. Want power just press a button and you can run both A/C units or anything else.
    Yes you pay for that convenience,however with a on board genset your RV is ALWAYS self contained.
    @ the OP my suggestion is contact a genset specialist or service company instead of an RV dealer.



    Also mom likes the ability of pressing a button on the wall and having power, I enjoy not having to worry about packing, unloading, gassing up, someone stealing it, having to run cords, and the ability to run it down the road or at a rest area for lunch. So yeah different options for sure.

    I did debate about solar as well, and an inverter,solar,converter combo but I camp in the woods often and batteries are $$$ the onan option is actually cheaper.

    I was debating on having a box made for me... just wasn't sure what all was in this box.

About Technical Issues

Having RV issues? Connect with others who have been in your shoes.24,188 PostsLatest Activity: Jan 18, 2025