Better Dash Heat??

[Greg2]

Family health is keeping us 'up north' until early January [grump] Anyway, i was just thinking, our 1998 Discovery with ISB Cummins fails to provide enough heat up front from the dash heater to satisfy the wife when traveling in cool weather. I shudder to think what I will hear while traveling in January.
So, I was wondering about bypassing the engine, and using a LP fired demand water heater [tankless] [Our Onan generator uses LP, so we have 2 tanks, as well as an Extend-A-Stay.] Seems like that would be a better idea than using the furnace the entire trip.
If you think it would work, does anyone have an idea of the flow required. I already know I would need a water pump to circulate the water, basically a demand pump that will handle hot water. And yes, I know about the shut off valves in the heater hoses near the engine. They are open.
Thanks.

[ahicks]

Nothing to do with your question. Just wondering if you have the cab heater set to recirculate interior air, or are you asking it to heat up possibly very cold exterior air?

[GraySeal65]

Does your coach have a "bus pump" ? Mine has one, it's a electric pump in the heater hose line. When they fail the impeller slows the flow of hot coolant up to the heater core.

[Greg2]

Originally Posted by ahicks

Nothing to do with your question. Just wondering if you have the cab heater set to recirculate interior air, or are you asking it to heat up possibly very cold exterior air?

Recirculate.

[Greg2]

Originally Posted by 92TNTRacing

Does your coach have a "bus pump" ? Mine has one, it's a electric pump in the heater hose line. When they fail the impeller slows the flow of hot coolant up to the heater core.

I don't think so, but I will find out. Good inquiry.

[dpinvidic]

Greg2, that is a very ingenious idea.
Our engine runs about 192 deg, a lot cooler than a car.
Then the long hoses act like a heat sink.
I have installed foam pipe insulation around the heater hoses from just behind the generator up to the heater core.
Also insulated the front cap.
One of the bigger helps was a expandable curtain rod and a temp curtain behind the seats to close off the rest of the RV.
Point of use heaters need a minimum flow to operate.
I would first try to just install the POU heater on the firewall, and set the temp to what you want. This way it acts like a booster, but you don't have to use it if not needed. this would use the normal engine water pump for circulation.

Then if needed turn on the POU heater.

Regard,

Dan

[ellisda1]

How about running the generator and powering a small space heater?

[gatorcq]

We have run the propane heater. Like the Rv to stay warm while we travel. For dash heater - make sure it is on recirculate - if your dash does not have that function, then locate the flapper door in front (outside) and tape it shut. Now how can you tell - traveling warm air coming out - park engine running - hotter air coming out.
A friend installed a heat exchanger (with fan) to the engine coolant line.
Run generator - plug in electric heater. You do not mention whether or not the A/C untis are heat pumps or heat strips.

[ahicks]

Is there a reason you don't want to run your propane furnace on the road? Set to recirculate, and picking up preheated air off the floor of the coach, our cab heater generally runs at a fairly low blower speed to keep us comfortable even in freezing weather. If that still doesn't do it, we just kick the furnace on with the t-stat turned to 68 degrees or so.

No concrete data to back me up, but I would think it might be more efficient than a propane fired water heater heating up coolant to be circulated through the cab heater.

We do the same thing in warmer weather. If the cab AC can't keep up on recirculate, we fire up the genny and one the front AC. Have never had the need to fire up the second AC.

[4x4van]

I agree with running the LP house furnace; I'm not familiar with DPs, so I may be off-base here, but I would think that the dash heater is designed to heat the cab area, not the whole coach. While it may do the job in mild conditions, it will never keep up in very cold conditions, nor is it designed to.

[ahicks]

Oh ye of little faith.

Most recently, this past September I was driving in semi freezing temps (northern Montana) wearing just a t-shirt, jeans and socks, with snow collecting on the windshield wipers, and very comfortable. Cab blower was on medium, and the furnace kicking on for just a few minutes here and there.

What may make ours a little different is our "recirculate" door is permanently open to allow the cab HVAC to pull it's air from the coach interior only. I simply zip tied the vacuum motor to hold it there. It's proven itself to be MUCH more efficient operating like this over the last several years in all sorts of temp extremes we've encountered while traveling all over the country. Keep in mind, this is a typical drafty nearly 20 year old coach. I have made no attempt to seal it in any way. Actually, that's how we get our fresh air! ;^)

While I agree the cab HVAC is not designed to heat/cool the entire coach, I believe that if given half a chance, it can do a pretty good job for the front seat occupants. Much better than a lot of people give them credit for anyway.

[dieselclacker]

A temporary curtain rod mounted
just aft of the front seats, and a blackout curtain from Walmart keeps us toasty when winter travel is necessary in our motorhome. Cutting down the area size to be heated by the dash heater, and using the recirculate feature on the heater controls works wonders.

[buxtonworks]

I installed a heater under the dash behind the two drawers in the front cab I'm always cold my wife is fine but bought the heater from summit racing it runs water from the main heater and ran power off 12 volt accessories works good I tink its 6 or 8 thousand btu pretty easy to do.


Monaco Knight 30 pbd 5.9 Allison 3000MH

[GoneRVn]

If it gets really cold and it does were I live, I turn the inverter on and plug in an electric space heater.
It keeps the wife very happy.