Can I drive with furnace running

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Can I drive with furnace running

November 12, 2014, 10:49:31 am

Stuck in historic freeze 100miles from home , can I drive with furnace running . Concerned about outside airflow causing back flow of gas

Re: Can I drive with furnace running

Reply #1 – November 12, 2014, 10:52:14 am

No problem, Watch if heavy wind from side, check often to see that burner is operating. Otherwise should work fine. If flame goes out safety device will kick in and cut off gas flow.
Good luck.
Gary B

Re: Can I drive with furnace running

Reply #2 – November 12, 2014, 10:54:31 am

Thanks Gary
I am going to keep gen running to support battery's

Re: Can I drive with furnace running

Reply #3 – November 12, 2014, 10:59:24 am

Should not have to keep genny running, Furnace is 12volt and as long as house batteries are being charged thru the isolator by the engine alternator you should have no problems. You might support the furnace with the heat strips in the AC's and in that case you will need the generator. I have driven in 10 degree weather with just furnace and dash heat. Wind is what will challenge temps in the coach, with following wind all will be well, head on wind and large glass area will keep temps in coach low.

Gary B

Re: Can I drive with furnace running

Reply #4 – November 12, 2014, 01:44:47 pm

You should not have to run the generator. Just the furnace. I did it that way with my 2 batteries on my 99 270 till I added two more. No issues.

Re: Can I drive with furnace running

Reply #5 – November 12, 2014, 03:26:29 pm

We use ours in route from Michigan to Florida in the winter with no issues

Re: Can I drive with furnace running

Reply #6 – November 12, 2014, 07:06:06 pm

Am I the only person who thinks it's an epic failure to design a coach with a huge diesel engine as a source of heat with only tiny hoses to get the heat to the heater / defroster? How come school buses have multiple heaters that work great in cold weather but a million dollar coach needs to leave the furnace running? ...please do explain if you're a Foretravel design engineer, just saying

Re: Can I drive with furnace running

Reply #7 – November 12, 2014, 07:30:16 pm

I agree with you that you should be able to heat that coach with the engine only. I just finished putting a heater in the middle of my coach and I ran separate
set of hoses to it. I have it set up so it will heat the water system as don't need frozen pipes. I wish my hot water heater was a motor aid and that would save money on propane as the heat of the engine is free. You don't need to run your generator to run your furnace as your
engine alternator will handle it. The furnace doesn't use much electricity

Re: Can I drive with furnace running

Reply #8 – November 12, 2014, 07:42:17 pm

I don't think you're missing much free hot water by not having the engine assist feature. After driving all day long you might get enough hot water for a very short shower. It's certainly not worth the hassle of installing it. I think I'm gonna investigate re-piping my heater / defroster with a much larger pipe. There's really no reason why I shouldn't have access to the huge amount of heat my engine is generating. I think I'm gonna pipe my diesel genset into the defroster too with a three way valve so I can use the generator's heat to defog my windshield before I start driving.

Re: Can I drive with furnace running

Reply #9 – November 12, 2014, 11:13:25 pm

Thats probably a great idea. I Had thought about that, just hooking it into the heater core and there is all that free heat when the generator is running.
If the water heater is a motor aid it isn't a big deal to hook it up, but not worth getting another hot water when the one I have is good. I set my motor home
for skiing so any way I can get heat I use.

Re: Can I drive with furnace running

Reply #10 – November 12, 2014, 11:56:19 pm

I can't speak about whether or not it would be worth the hassle, but I found the motoraide feature to be very effective. The first time I took our coach from the house after getting the bulkhead repair finished, I was very surprised to find that the water was as hot as if the propane or electric element had been on. This was on a 30 minute run. The reason I was so surprised was that I had just finished putting in the new 3 way water heater (the old one was also a 3 way) and I had taken the styrofoam insulation off (can't remember why) and found that the motoraide loop was a short length of tubing welded to the aluminum tank. I had thought that it would be a heat exchanger inside the tank... I was quite surprised that the contact area was enough to transfer that much heat in only a 30 minute drive. Just my experience...
Don

Quote from: RRadio – November 12, 2014, 07:42:17 pm

I don't think you're missing much free hot water by not having the engine assist feature. After driving all day long you might get enough hot water for a very short shower. It's certainly not worth the hassle of installing it.

Re: Can I drive with furnace running

Reply #11 – November 13, 2014, 12:18:45 am

Electric and propane = 140 degree thermostats. Engine coolant = 180 degree minus line losses. Our U270 always put out hotter water on the engine (no thermostat on that engine loop), than on electric or propane.
16 years, never a problem, KISS.
Neal

Re: Can I drive with furnace running

Reply #12 – November 13, 2014, 06:15:30 am

That is the beauty of the aquahot. It does heat the whole coach with just the engine heat. At least if it is not too cold out but I have not had to turn on the furnace when driving yet. You might lose more heat then you should and get too cold to run efficiently if you upsized the lines. I know if it is really cold I will cover up some of my radiator to help the truck get to operating temps. Now we do not have ram air radiators but the same thing applies.

Re: Can I drive with furnace running

Reply #13 – November 13, 2014, 03:33:20 pm

I guess there must be something wrong with my engine assist thingy on my water heater. If I drive all day I get enough hot water for a very short shower. With only 30 minutes of driving I wouldn't have any hot water at all. I just checked and the valve is open, so that's not the problem.

Re: Can I drive with furnace running

Reply #14 – November 13, 2014, 04:04:30 pm

Ok, it's time for the dumb question of the day: how would I know if I had the "motor aid" function in our coach? Take it easy on me; I've only owned it for 2-1/2 years.

Re: Can I drive with furnace running

Reply #15 – November 13, 2014, 04:53:38 pm

Quote from: acousticart – November 12, 2014, 11:56:19 pm

I found that the motoraide loop was a short length of tubing welded to the aluminum tank. I had thought that it would be a heat exchanger inside the tank... I was quite surprised that the contact area was enough to transfer that much heat in only a 30 minute drive. Just my experience...
Don

My guess is that the manufacturer put the heating loop on the outside of the tank in order to be absolutely sure that no engine antifreeze would ever get mixed in with the coach water resulting in health problems, maybe death, and law suits.

Re: Can I drive with furnace running

Reply #16 – November 13, 2014, 05:10:33 pm

Some one may have already posted this

Scott....the older FT's (our 94-U225) has a gate valve under the sink that controls how much engine water goes to the dash heat and how much goes to help heat the hot water tank !
Never have figured out how to get it regulated just right, seem to have plenty for both the way it is, so I just try to screw up something else...........~Johnnie~

Re: Can I drive with furnace running

Reply #17 – November 13, 2014, 05:19:03 pm

On my U295, 98 model the on/off valve is near the floor of the water heater compartment. With a mirror and the right light, you can maybe see 2 sets of hoses on the back side of the tank. Black hoses are engine coolant hoses. The lighter colored ones are fresh water. You might be able to reach up behind the tank as well with luck to find 4 hoses.

Re: Can I drive with furnace running

Reply #18 – November 13, 2014, 08:00:03 pm

My valve is under the water heater, not under the kitchen sink. It's open all the way, I just checked it before I wrote that. Maybe the coolant filter is on that same hose and it needs to be changed? ...I dunno, I'm just taking wild guesses at this point. I can't think of any reason why my water heater wouldn't work as well as everyone else's. I just drove from Maine to North Carolina with the valve wide open and it didn't make much hot water.

Re: Can I drive with furnace running

Reply #19 – November 13, 2014, 09:17:29 pm

Quote from: RRadio – November 13, 2014, 08:00:03 pm

I can't think of any reason why my water heater wouldn't work as well as everyone else's. I just drove from Maine to North Carolina with the valve wide open and it didn't make much hot water.

Well I can think of one. Foretravel added a boost pump to the water line that leads to the dash (and waterheater motoraide) on 6V92s. I guess the Detroits need it for some reason.
So was that pump running on your trip?

Re: Can I drive with furnace running

Reply #20 – November 13, 2014, 09:19:07 pm

@Scott My coach is only a year newer than yours so would think they are very similar. After our usual 300 mile day the water is plenty hot to take a shower.

Mine does have a pump that is controlled by a switch on the dash that circulates the coolant to the front of the coach by way of the motor-aid. You might check to see if you have one and that the pump is working.

I've heard that the coolant filter isn't so much a filter but more of a SCA refresher.

see ya
ken

Re: Can I drive with furnace running

Reply #21 – November 14, 2014, 07:51:55 am

I think the electric pump is only on the 40'ers

Re: Can I drive with furnace running

Reply #22 – November 14, 2014, 08:34:04 am

Quote from: RRadio – November 13, 2014, 08:00:03 pm

My valve is under the water heater, not under the kitchen sink. It's open all the way, I just checked it before I wrote that.

On our 1997 U295, the water valve for water heater/dash heat using engine coolant appears to be designed to adjust the flow between the two. You can get more heat for dash, or for water heater, depending on the setting of the valve. I changed it one time and couldn't tell much difference. I generally leave it open, which supplies hot water to both devices.

We have traveled in 0F air temperatures. We had plenty of hot water from the motor aid, and a fair amount of heat from the dash air. We did use some supplemental heat for the cabin with a combination of a ceramic heater and the propane furnaces. We were generally driving 65 mph on Interstate highways, so the engine was generating plenty of heat.

Re: Can I drive with furnace running

Reply #23 – November 14, 2014, 09:58:43 am

My 36' U300 has the electric aux pump controlled from a switch on the instrument panel. I know that it works. I used it some of the trip, when the defroster wasn't hot enough. I don't leave it on all the time, only when I need it. I've never tried driving with the valve closed so all the hot water goes to the defroster. Maybe I'll try that the next time I'm driving in cold weather... hopefully never! haha

Re: Can I drive with furnace running

Reply #24 – November 14, 2014, 11:11:22 am

Quote from: RRadio – November 13, 2014, 08:00:03 pm

My valve is under the water heater, not under the kitchen sink. It's open all the way, I just checked it before I wrote that.

You might need to try closing it all the way. I can never remember what needs to happen, till I read the tag on the handle. Could be your 100% wrong with your valve. We always have a shower or two when we arrive, without fail.

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