Installing 4" wide heating registers?

[StrongJava]

I've noticed many of the newer coaches have 4" wide register covers while my 2008 Bighorn has 2" wide. I priced 4x10 registers at Lowe's/Home Depot, and they are about 1/2 the price of the 2" wide registers at Camping World.

I'm considering changing the size of the rough opening so I could use 4" wide registers. I'm not HVAC expert, but wouldn't that perhaps help me get more heat into the areas I want it? I realize the duct work is still unchanged, but it seams my furnace vents more heat to the outside than it does to the inside!

Any thoughts regarding if this would help? Gotchas I should consider?

Tim

 

[JohnDar]

All of ours were 4x10, so changing to adjustable registers was a no-brainer. But if you have 2" wide registers, then the "box" it sits in is probably the same size. You will need to remove it, cut the floor opening wider, and reattach the duct to the new box. If you have 2x10 registers, what is the diameter of the flexible hose that feeds it? Just changing the register won't result in any more air flow if the hose is only 2".

 

[StrongJava]

Thanks John. I'll have to get underneath to measure the flexible hose. However, my registers all up up of a box ducting that runs longitudinally with the RV. It is about 12" wide, and 2" deep. So, to cut the floor to a 4x10 is a fairly trivial job, I think. It appears a lightweight tin (or, a heavy duty aluminum foil) is used to create seals from the box through the register hole.

Unfortunately, all of the register dampers except one are broken off, which means I'd have to spend at least $50 to buy new registers at Camping World. Right now I'm putting magazines over the ones we want to close. We're at Quartzsite and will look again tomorrow at the show to see if anyone has them for sale.

 

[pegmikef]

Thanks John. I'll have to get underneath to measure the flexible hose. However, my registers all up up of a box ducting that runs longitudinally with the RV. It is about 12" wide, and 2" deep. So, to cut the floor to a 4x10 is a fairly trivial job, I think. It appears a lightweight tin (or, a heavy duty aluminum foil) is used to create seals from the box through the register hole.

Unfortunately, all of the register dampers except one are broken off, which means I'd have to spend at least $50 to buy new registers at Camping World. Right now I'm putting magazines over the ones we want to close. We're at Quartzsite and will look again tomorrow at the show to see if anyone has them for sale.

I think I read somewhere on this forum that closing or blocking some of the vents can lead to the furnace overheating and damaging some of the components. Unfortunately, I don't remember the specifics but the discussion was about blocking bathroom vents to force more heat to the bedroom.

 

[danemayer]

I think I read somewhere on this forum that closing or blocking some of the vents can lead to the furnace overheating and damaging some of the components. Unfortunately, I don't remember the specifics but the discussion was about blocking bathroom vents to force more heat to the bedroom.

Suburban strongly advises against blocking vents/ducts because 1) it may reduce the ability of the blower to activate the sail switch, resulting in intermittent failures, and 2) it may cause the temperature in the combustion chamber to reach a higher than normal temperature, activating the high-limit switch, which cycles the burner on and off before reaching the desired temp in the coach. Also, the switch may not be rated for a large number of cycles and could result in a service call.

That all said, many people do partially restrict some ducts to even out temperatures throughout the coach. If you do so, make yourself a note so if you start experiencing intermittent problems, you'll remember to go back and revisit the ducts.

 

[StrongJava]

Re: Installing 4" wide heating registers?

I read it too when searching before posting this link. I am comfortable blocking or reducing the flow through a couple at a time. After all, register dampers are designed to do just that.

I think I read somewhere on this forum that closing or blocking some of the vents can lead to the furnace overheating and damaging some of the components. Unfortunately, I don't remember the specifics but the discussion was about blocking bathroom vents to force more heat to the bedroom.

- - - Updated - - -

Hi Dan,

I read that discussion thread, and it is good to know. I'm also leaving about 1/2 fully unencumbered. But I'm also trying to get some control over where more of the heat is directed.

Any thoughts on why I *shouldn't* open the vents up to the larger size of 4x10?

Tim

Suburban strongly advises against blocking vents/ducts because 1) it may reduce the ability of the blower to activate the sail switch, resulting in intermittent failures, and 2) it may cause the temperature in the combustion chamber to reach a higher than normal temperature, activating the high-limit switch, which cycles the burner on and off before reaching the desired temp in the coach. Also, the switch may not be rated for a large number of cycles and could result in a service call.

That all said, many people do partially restrict some ducts to even out temperatures throughout the coach. If you do so, make yourself a note so if you start experiencing intermittent problems, you'll remember to go back and revisit the ducts.

 

[danemayer]

Re: Installing 4" wide heating registers?

Hi Dan,

I read that discussion thread, and it is good to know. I'm also leaving about 1/2 fully unencumbered. But I'm also trying to get some control over where more of the heat is directed.

Any thoughts on why I *shouldn't* open the vents up to the larger size of 4x10?

Tim

Tim,

If you have a Suburban SF42, I'd guess (strictly a guess) that changing 2" wide registers to 4" wide registers would help the furnace function more efficiently.

 

[StrongJava]

Re: Installing 4" wide heating registers?

I'll have to pull the cover. I have installation manuals and user manuals for all SF-2X, SF-3X and SF-4X series

I suppose I'll just bit the bullet and buy new 2" registers. I know balance between the registers is important for efficiency, and if too much gets pulled from the ducting before the warm air gets to the end of the line, heating at the ends won't be effective. I definitely need new dampers though.

Tim,

If you have a Suburban SF42, I'd guess (strictly a guess) that changing 2" wide registers to 4" wide registers would help the furnace function more efficiently.

 

[JohnD]

Don't buy those plastic vent covers from Camping World . . . this is what happened to the two I bought after about 10 minutes of heat:



You can get metal vent covers the right size at Home Depot or Lowe's.

 

[StrongJava]

Thanks, John.

I found some metal ones locally here in Quartzsite. I paid more than I would have liked, but the closest HD/Lowes only have the 2x10s in white, if at all.

 

[JohnD]

Thanks, John.

I found some metal ones locally here in Quartzsite. I paid more than I would have liked, but the closest HD/Lowes only have the 2x10s in white, if at all.

Cool!