Flying Insect Screens for Furnace

[TomW]

One of the last problems my Airstream's last furnace had was a yellowjacket nest which partially clogged up the works. To keep that from happening in the new Suburban NT-30 furnace I just installed, a set of exterior vent screens was purchased.

To my surprise the Installation Manual specifically states, "WARNING! Do not install screens over the vent for any reason. Screens will become restricted and cause unsafe furnace operation. Accessories are being marketed for RV products which we do not recommend. For your safety, only factory authorized parts are to be used on your furnace."

After weighing the pros & cons I still think the screens are a good idea. Anyone disagree?

Thanks,
Tom

[Bubba L]

Have used those for years without issue. I just make sure they don’t get clogged up with road debris.

[batman]

Sorry, I do not have the same heater as you any more. I converted to a Precision Temp, Twin Temp JR.

However, I do use those same covers for my vent pipes on top of the trailer.

In My Opinion, As long as you keep them clean and clear there shouldn't be a problem. Once again free advice is worth what you paid for it. If it were me, I would use them. Leave them on until you want to use the furnace, then remove them if you are worried about it. They come off easy, or just undo one side at the time you want to use the furnace.

We have used these on a class A with no issues.


-Dennis

[rmkrum]

I also installed a large rectangular screen over the whole integrated intake/exhaust vent on my furnace. I figure it’s easy to clean and big enough to not block airflow.

[WhereStream]

Here in bug-filled Florida, we use the screens.

Dealer strongly recommended them.

[Protagonist]

The key is something called "equivalent opening area." You furnace exhaust has a certain cross-sectional area based on its diameter. The dome-shaped screens have a certain surface area based on their shape. As long as the surface area NOT filled by the wires of the screen is larger than the cross-sectional area of the original exhaust, the flow will not be restricted in any way, and the screens will not do any harm.

[SailorSam205]

At a rally sponsored by the manufacturer of my RV, we had a company representative make a presentation. He specifically brought this up. It isn't the RV manufacturer who has the requirement, it's the furnace manufacturer. The RV manufacturer is contractually required to enforce this specification. With all that said, he said that "If the screens are kept clean" there isn't an issue, however, if you bring your RV in for warranty service or send me pictures that will be used for warranty reasons, take the screens off first. What I don't know won't hurt you."

So keep the screens clean, even spider webs or tree floss can reduce air flow. And take the screens off before visiting your dealer.

[57Vintage]

I've screened my Suburban furnace to keep out the bugs. No problems last fall or so far this spring. I went with a rectangular one like below to have more surface area covered.

https://www.camperid.com/jcj/m200-rv...specifications

[rmkrum]

That looks like to one I used. Covers the whole vent assembly on the back of my trailer.

[SYC2Vette]

My dealer installed mine prior to delivery. Like said, easy enough to inspect them to make sure they are clean.

[pappy19]

Originally Posted by SYC2Vette

My dealer installed mine prior to delivery. Like said, easy enough to inspect them to make sure they are clean.

Used them for years on my AS. Also, every spring I buy 2 large dog flea and tick collars and cut them into 3-4 " pieces and put them in every place that has an opening, water heater, fridge, heater, and hang one inside the propane tanks. No more bugs or spiders.

['55 Airlight]

I've got a screen over my furnace intake/output vent. But I couldn't stand the idea of the metal edge riding against my vintage aluminum, so I acquired some surgical tubing, sliced it and slid it over the metal edge so the screen rides against the surgical tubing which presses on the aluminum skin.
Michael

[tbashin]

I use them for mud daubers and yellow jackets and have never had an issue with those bugs or the operation of the heater since. Make sure you get the ones that fit properly.

[dhroberts]

I use a screen very similar to the one in your picture. For the water heater, I have adhered a screen to the inside of the door. I examine them prior to beginning any trip. Reading your post will prompt me to be extra diligent in my examinations. I assume that the manufacturer's warning to not use screens is a liability management effort.

[perryg114]

They are fine. As Protagonist said as long as you are not changing the area of the inlet and outlet, you are fine. That is why the screens are dome shaped and/or standing off from the orifice. It is much more likely that you will have much more severe blockages from these insects. I just cleaned a furnace out and every orifice in the thing was clogged. The burner was full of dirt dauber nests and lady bugs. The actual gas jet was clogged with no see ums. You are far safer with a screen than without.



Perry