Heat Ducting

[ArmyEOD]

Has anyone reworked their heating duct? I am thinking of redoing mine to cut down on heat lose and get more hot air to the vents. I am sure there must be a better way other than the super thin ducting I have now. Anyone got any thoughts?

[njs42]

I'm just wondering how much pain for how much gain. I pondered your question and have been trying to think of just how accessible my vents would be and if I wrapped them in insullation how much of a problem it would be---it left me wishing I was 100 pounds lighter and 15 year younger---maybe you are.

Is there is a way to really determine how much heat loss you are really experiencing? And how much gain you would get---if I did not expect a huge return for the effort I guess I would pass. I know the pipes in my rig are very thin---and like most of us I wish the furnace was a bit more efficient. But in reality over the time that mine is used (four months per year)---would I save that much propane cost to justify? After all I can crank it up when it is really cold-----I assume you can as well.

I solved some of my problem by putting the adjustable vents on more outlets thereby being able to close off a vent and route more heat to strategic areas---particularly at night; which is when we use the furnace the most anyway.

Perhaps there is pre insulated pipe? If so then maybe it would make the job easier. I imagine a place like Lowes would carry it, for my own edification I will look next time I am there.

To be fair most of my travels are in warmer climates---that is why I go there---but still I have had 19 degrees for a week running----and just hogged up a bunch of propane-----and endured the noise of my furnace running pretty much constantly---other wise warm.

Also I should add I have heat pumps in addition to my furnace so I can, depending on temperatures, make a choice.


Any thoughts? Sure---but are they helpful?

[az bound]

x2 for the adjustable registers. It sure helped to even out the temps by redirecting heat to cold areas.

[Diplomat Don]

ArmyEOD....I don't thonk there is much you can do to them. The tubing runs through foam cutouts in the ceiling. I did remove the filter screen and made sure that the airbox was sealed well. You can use silver tape to make sure everything is sealed inside the unit.

I do as others do and shut some vents down to direct cooling.

[ArmyEOD]

Thanks for the replys. I have already cleaned out the ceiling vents, trimmed the vents to ensure an even flow and cut down wind noise thats about all I can do with it. Now I want to do something with the furnace ducting. I can see that the current ducting comes from one of the the unit and then runs to the registers under the kitchen cabs, It supplies force air to 2 vents. One of the vents blows into the kitchen from the cabinet kick plate, and the other blows into the side of the couch at the end of the cabinet. When the heat is own I get a lot of heat lose. It gets really hot inside the cabinet and the end of the couch gets hot. I was just thinking about cleaning it up and change to a better quailty duct material and splitter design where it feeds the vents, and maybe relocate the one that blows on the couch so that it will blow out from under the couch. Following the advice above I will change to adjustable vents also, From the same heat unit it has a duct that provides force air to the bathroom. It get very little heat out of it. I am thinking it may be crimped or not connected. I want to fix that to. On the other side of the rig is the second furnace. It is located under the fridge. It works well just cheap duct material with heat lose befor it gets to the vents.

[nodine]

Quote:

Originally Posted by ArmyEOD Thanks for the replys. I have already cleaned out the ceiling vents, trimmed the vents to ensure an even flow and cut down wind noise thats about all I can do with it. Now I want to do something with the furnace ducting. I can see that the current ducting comes from one of the the unit and then runs to the registers under the kitchen cabs, It supplies force air to 2 vents. One of the vents blows into the kitchen from the cabinet kick plate, and the other blows into the side of the couch at the end of the cabinet. When the heat is own I get a lot of heat lose. It gets really hot inside the cabinet and the end of the couch gets hot. I was just thinking about cleaning it up and change to a better quailty duct material and splitter design where it feeds the vents, and maybe relocate the one that blows on the couch so that it will blow out from under the couch. Following the advice above I will change to adjustable vents also, From the same heat unit it has a duct that provides force air to the bathroom. It get very little heat out of it. I am thinking it may be crimped or not connected. I want to fix that to. On the other side of the rig is the second furnace. It is located under the fridge. It works well just cheap duct material with heat lose befor it gets to the vents.

George,

We have the same coach as you and the same issues with the furnace ducts. I believe there are only three vents on the unit under the frig, one coming out under the frig and blowing under the dinette, one in the bath area and one in the bedroom. The registers in the bath and bedroom area seem to be partially blocked but are difficult to access. The registers on the kitchen side provide plenty of heat to the dinette side so I stopped up the round vent coming out from under the frig. That gave a little more heat to the rear but still needs improvement. We use the heat pumps when we can but improved heat to the rear would be nice and is on my list of things to do. I don't worry to much about heat loss in the ducts because that heat is mostly leaking side the coach. Sometimes I wish there was a little heat going to the basement area to keep stuff stored there from freezing.

Sorry we missed you at the FMCA rally in Perry.

Bob

[rpasetto]

Home depot has insulated flexible duct in 4" size, which is probably what you have, for about $25 for a 25 ft length (they also have it in 6" and 8"). The tough part you may run int owould be to fit the added thickness without crushing the duct, which would reduce the internal cross section thus reducing air flow. You could also slip the next larger size duct over the existing ductwork or get duct insulation.

[Robi.1014]

George,
I'm supporting Bob's comment: "....heat is mostly leaking [in] side the coach."

Having been in some nasty-cold weather, I was surprised at how cold the voids were (void examples: under my roadside sofa or under my bedroom vanity-drawers....i.e., locations thru which there is no furnace hosing).

I'm OK with furnace hose heat-loss in that the voids that these hoses occupy are benefiting from the warmth cast off from the hose. As you probably have experienced, when the furnace turns off, cold air just seems to creep back in from EVERYWHERE, but it seems more pronounced as it creeps into the living space from a non-heated void. Burrrrrrrr!!

Engineering term for this case: "delta"....the temperature difference between one space (a void) an another (our living space). The lower the delta, the better. Propane used? The difference is probably not distinguishable.

[Diplomat Don]

Sorry.....I read this wrong and spoke about the A/C. Now that I'm on the right subject, I'll high jack this a little with a similar question.

We don't use the furnace that often, but when we do, it runs for several minutes, shuts down and a few minutes later will run again. This has been going on since new and does it when we first fire it up in a cold coach and it needs to play catch up. It almost seems like it overheats, shuts down and then starts up again. I've checked the unit and there doesn't seem to be any issues with obstructions or lack of air space. Do others experience this. We do get good even airflow at the two registers in the main living area, the bath and bedroom.

[RVhauler]

sounds like it may be operating on the high temp stat (safety) instead of thermostat

[nodine]

Quote:

Originally Posted by Diplomat Don Sorry.....I read this wrong and spoke about the A/C. Now that I'm on the right subject, I'll high jack this a little with a similar question. We don't use the furnace that often, but when we do, it runs for several minutes, shuts down and a few minutes later will run again. This has been going on since new and does it when we first fire it up in a cold coach and it needs to play catch up. It almost seems like it overheats, shuts down and then starts up again. I've checked the unit and there doesn't seem to be any issues with obstructions or lack of air space. Do others experience this. We do get good even airflow at the two registers in the main living area, the bath and bedroom.

Don,

I think I know what your problem is as we had the same issue. If you look in the bedroom and in the living area for the remote temperature sensing elements you will find that they have been located back inside the wall. Most of us have pulled them out and used a piece of cork to protrude the tip out into the air space of the room and not the wall. There was a post on this last January while we where down in Florida. I'll look back and see if I can locate it.

Here it is:
Are you having trouble with temp control in your coach?

Bob

[ArmyEOD]

Thanks to all for your comments. I am in NJ right now in a hotel (Sad Face) for another couple of weeks. I will try and post some pics of what I do to improve the overall flow of the ducts.