Replacement Propane Furnace

[N147JK]

My van has the typical 100% on or 100% off cycling propane furnace. It heats the cabin alright, but it's noisy and it just seems like a crude way of doing the job.

Does any manufacturer make a quiet furnace, something that will heat using a very low setting, run quietly with a low-speed fan, for longer periods of time? Something that doesn't cycle on and off so abruptly?

[rowiebowie]

Originally Posted by N147JK

My van has the typical 100% on or 100% off cycling propane furnace. It heats the cabin alright, but it's noisy and it just seems like a crude way of doing the job.

Does any manufacturer make a quiet furnace, something that will heat using a very low setting, run quietly with a low-speed fan, for longer periods of time? Something that doesn't cycle on and off so abruptly?

I can't help you, but I can sympathize. It's more the cycling you describe that bothers us than the fan noise, although the fan is too noisy. For too many years, quiet operation of water pumps, roof a/c's, and furnaces was not a priority for the appliance manufacturers. We like a constant noise while sleeping (a sound machine at home), a fan when hot, roof a/c on "constant" fan when plugged in, and wish there was a constant fan option for the Suburban furnace.

It would seem that should be a simple option for the furnace. Perhaps it would feel drafty during periods when heat was off, but is seems a constant fan is something that could be re-wired without interfering with the safety of furnace operation.

When it's cold and we're plugged in, we use a small electric heater. Quieter than the propane furnace. So quiet that we don't notice as it cycles on and off.

[eric1514]

Originally Posted by N147JK

My van has the typical 100% on or 100% off cycling propane furnace. It heats the cabin alright, but it's noisy and it just seems like a crude way of doing the job.

Does any manufacturer make a quiet furnace, something that will heat using a very low setting, run quietly with a low-speed fan, for longer periods of time? Something that doesn't cycle on and off so abruptly?

A few years ago I seem to remember Suburban came out with a quiet version of their furnace. It is a little quieter but it still operates like the one you have at one speed and either on or off.

[gregmchugh]

Winnebago has started using the Truma VarioHeat propane heater. You might contact Truma and see if there is a dealer that installs them.

https://www.truma.com/int/en/product...t-comfort.html

[booster]

Gas air to air furnaces are fairly complicated and certainly not cheap. We are just now starting to see 2 speed and continuous variable speed and output furnaces for homes. Much of the now available is due to the ECM motors they have now which allow precise speed control. Propane is also a bit harder to deal with than natural gas in needing careful purge and delay times.


The Suburban you may have, and we have the "quiet" version of now, uses a single motor for the burner draft and the cabin fan, so probably poorly suited to any variable firing. It may be able to be run with continuous fan but at one speed and the draft fan would also be spinning and moving air.


Your best best for variable output might be with one of the glycol based liquid heat exchange units, but I know little about them.

[rvsprinterguy]

We share your annoyance with the loud Suburban furnace fan. Like other posters, we use a small electric heater in cold weather, if we can plug into AC.

[hbn7hj]

We found great benefit in turning the furnace off at night and using heated mattress pads. For us it takes an inverter and lithium batteries but it works. Saves propane. Use the furnace when you are awake.

We do set the furnace for 45-50F but it usually does not come on with outside temps in the 30s.

[hbn7hj]

Just checked. A 1500 watt inverter with a mattress pad set on 3 draws about 1.9 amps. We have found the electrical draw of the mattress pads matches the electrical draw of the furnace overnight. Considering you don’t have the propane use we find it a better way to go.

You do have to heat things up in the morning and the furnace runs a bit to do that.

[eric1514]

Originally Posted by hbn7hj

Just checked. A 1500 watt inverter with a mattress pad set on 3 draws about 1.9 amps. We have found the electrical draw of the mattress pads matches the electrical draw of the furnace overnight. Considering you don’t have the propane use we find it a better way to go.

You do have to heat things up in the morning and the furnace runs a bit to do that.

What mattress pad is that? I'm trying to run down my batteries for science and I have two small electric throws/blankets that draw 10 amps each. They've been on now for 7 hours now and have used 61 Ah.

[hbn7hj]

Originally Posted by eric1514

What mattress pad is that? I'm trying to run down my batteries for science and I have two small electric throws/blankets that draw 10 amps each. They've been on now for 7 hours now and have used 61 Ah.

Electrowarmth

They have AC and DC mattress pads. I use AC. They don’t give current requirements. Shame on them.

https://electrowarmth.com/

Amazon carries them.

[cobratom]

Truma is about the only system that is completely variable speed both on heat output and air output. Unfortunately Truma has a policy of not selling to the aftermarket, and can only be purchased with a new van or RV.
There is one non-traditional option available; http://www.trumaheaters.com

[N147JK]

Thanks for the replies. Disappointing.. either nothing at all, or systems that are far more complex and expensive than what's needed.

Here's an opportunity for an ambitious young mechanical engineer to step in and design something that is small, inexpensive, and does this (seemingly) simple job.

[ks@yvr]

Webasto (partially variable) and Eberspacher heaters (I believe fully variable) are two heaters that work very well and are quiet (as long as you have optional mufflers installed) compared to Suburban heaters. They both don’t cycle on/off like the Suburban propane heaters but give a constant heat. Planer is another company and so is Propex (propane)

More heat (larger unit) is not necessarily better as these units are meant to provide consistent steady heat rather than high btu’s and shut off. I currently have a Webasto 2000 STC and it has been more than enough heat to the single digits F for mid sized van (148”); the 4/5K models would have been too much heat. I would say it is more than equivalent heat output compared to my old noisy Suburban heater in the previous van.

[N147JK]

Originally Posted by ks@yvr

I currently have a Webasto 2000 STC and it has been more than enough heat to the single digits F for mid sized van (148”); the 4/5K models would have been too much heat. I would say it is more than equivalent heat output compared to my old noisy Suburban heater in the previous van.

I see Webasco has a version that runs on gasoline. Is that the version you have?

[gregmchugh]

https://faroutride.com/webasto-vs-propex/

[ks@yvr]

Yes my Webasto is the gasoline version.

[Peder_y2k]

How about using a catalytic heater such as the Olympic brand. Our wall mounted unit makes a very gentle steady sssss gas flow sound almost imperceptable, and the vent blower hums continuously and very quiet. Has very little on-off cycling......but then we dont go camping when overnight temps drop below 50°f

[Theputnams515]

Originally Posted by ks@yvr

Yes my Webasto is the gasoline version.

Any fire concerns here? Any smell issues etc?

I like the idea of a diesel heater but gasoline makes me nervous for some reason.

[gregmchugh]

Originally Posted by Peder_y2k

How about using a catalytic heater such as the Olympic brand. Our wall mounted unit makes a very gentle steady sssss gas flow sound almost imperceptable, and the vent blower hums continuously and very quiet. Has very little on-off cycling......but then we dont go camping when overnight temps drop below 50°f

In colder temps you get too much condensation with direct propane heaters unless you get a lot of ventilation from outside which reduces the heating efficiency.

[knmtravel]

Originally Posted by cobratom

Truma is about the only system that is completely variable speed both on heat output and air output. Unfortunately Truma has a policy of not selling to the aftermarket, and can only be purchased with a new van or RV.
There is one non-traditional option available; http://www.trumaheaters.com

Truma doesn’t offer dealer warranty on after market installed systems but we are going with this source to get one and will have it professionally installed in our bus when we get our under mount propane tank installed. The Truma Combi furnace and water heater was the best feature of our Travato. I see no good reason to be concerned with Truma’s internal policies. There are enough parts from junked rigs at this point to acquire anything that needs replacement when it fails.