rfsod48

Engine Block Heater & Air System Questions In Freezing Temps

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rfsod48   

Is there any problem or downside with leaving the engine block heater  on all night?

We will be leaving Michigan this coming Saturday and the overnight temperatures are going to be -11. I will have the motorhome at my house overnight and will be able to have it plugged in so I will be able to do this. It would be plugged into a 30 amp circuit, would I also be able to run furnace or might that be to much draw?

Roland                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           .  ,                                                                                                                                                                                                                                                                                                                                 

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wolfe10   

Roland,

Other than extra power consumption, no problem with leaving the block heater on overnight.

That plus charging the batteries to power the fan for a propane furnace should be no issue in terms of total amp draw.

If batteries deeply discharged, wait to turn on on the block heater until amp draw from charger has dropped off.

 

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rfsod48   

Brett, if the unit is plugged into my house will the fan use unit batteries or house current? 

 

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wolfe10   

The furnace fan is 12 VDC.  Your converter or inverter/charger will use 120 VAC from shore power to charge the batteries.

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Roland,

Not sure if you're location will allow it but have you thought of running your generator several hours ahead of departure?  That way you can run most of your "comfort" systems and be ready to go come departure time.

Blake

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rfsod48   

Blake, unfortunately we live in a condo and running gen over night not an option.

Brett, when running down highway is it not necessary to run generator, will alternator keep batteries charged to run heater fan? Do Ineed to turn inverter on at control panel? I always keep it off because when on and coach sitting in storage for longer period batteries go way down.

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wolfe10   

While driving, the alternator will keep both chassis and house  banks charged (yes, assuming it is working as designed/built)

Inverter on only if you have 120 VAC items you want to run while driving (limited to output of alternator less other loads).

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rfsod48   

Thanks.                                                                                                                                                                                                                                        

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fagnaml   

Roland --

My petroleum refinery experience leads me to ask about the "diesel" in the tank of your motorhome.  With -11 F weather, I hope you either filled up with No.1 Diesel (kerosene) or used the  proper amount of an anti-gel additive.  The "cloud point" spec for winter ULSD (No.2 Diesel) in most parts of the U.S. is +10 F max (cloud point is the temperature at which wax crystals start to form).   By contrast, the cloud point for No.1 Diesel (kerosene) is typically -40 F.   Wax crystals in diesel fuel will rather quickly plug fuel filters.

The few times I've used an anti-gel additive I bought Power Saver Diesel Fuel Supplement / Anti-gel at my local Walmart --> http://powerservice.com/psp_product/diesel-fuel-supplement-cetane-boost/

Your -11 F temp makes the Houston area's 20 F temp tomorrow morning quite balmy!

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rfsod48   

Mike, we do use antigel additive.#1 diesel fuel is sometime hard to locate. While we do have cold here in Michigan this latest spell of cold is not normal.

Roland

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garyreed   

As Bill mentioned above, you could plug it in for a couple of days before hand. Unless you warm the engine before you plug it in, it may draw to much juice and kick a breaker even with the charger on low. If you can, plug it in a day or two before you want to leave in case it does kick the breaker you will have more time to find the problem.

Just as important as fuel, make sure you purge the air tanks while it is warm so it will have less of a chance to freeze when you take off. Also on that note, in cold weather I have recomended to my customers before they leave, to cycle the air system a couple of times and let the air drier pop off a few times. In the case it is frozen you will know before you leave and not 50 miles down the road when you are parked on the side. Always keep some airline antifreeze or alcohol on hand, it also helps in the summer time.

Gary

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wolfe10   
17 minutes ago, garyreed said:

AUnless you warm the engine before you plug it in, it may draw to much juice and kick a breaker even with the charger on low.

Gary

Gary,

Would you please explain that statement.  The heater is a resistance heater.  Usually in the 750-1200 watt range.  Can't see how it would draw different wattage with different temperatures.

And turning on more than a couple of hours before starting will only serve to burn electricity.

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garyreed   

Yes Brett, you are right. In a perfect scenario it would be OK. I was going off the age of their coach and the previous use that the heater may have had. I am by no means an electrician, but experience over the years has taught me that as those things get older, whether by reason of calicfied build up, sludge, cord ect. they may draw more electricity than when new.

As far as the two hours, yes it would bring the temp up to where it may start easily. If it were plugged in overnight, the temp would be closer to operating temp and everything  (radiator, fan hub, alternator, steering pump, transmission ect.) would be warm. I know it would cost a little more to run all night but for me I would rather do that than crawl  in there at -11degrees in the morning. I have to lift the bed to plug mine in. As far as the cost, it used to be around $1-$2 to be plugged in overnight, probably a little more now.

Gary 

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FIVE   

I set a timer to have my engine block heat come on about four hours before departure.  If really cold, I give it another two hours.  Also put a trouble light with a 60 watt old style bulb to warm the starting batteries.

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wolfe10   
20 minutes ago, FIVE said:

I set a timer to have my engine block heat come on about four hours before departure.  If really cold, I give it another two hours.  Also put a trouble light with a 60 watt old style bulb to warm the starting batteries.

A good idea, as long as the timer is rated for the amps that the heater draws.  Most box stores have 20 amp timers-- a good choice.

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If I am leaving the next day I leave my block heater on over night. The coldest I have had to start in was 5 deg. at the top of Raton Pass. That is a bunch of cold iron and water to try and warm up in a few hours. 

Bill

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ObedB   

Truckers with the ability to plug a block heater in,  leave  them on for the few days that they are not running hard to make a living. They get used much more than our toys do and none the worse for the wear. If one decides to leave early, it is nice to know that the engine will enjoy a somewhat easier start.

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rfsod48   

Bill, that is what I plan to do, we will have the mh over night before leaving and I can run a cord to plug it in from my garage. What is this about purging the air tanks?

Roland

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manholt   

Roland.  Some coaches, like the 07 WB Tour I had, I would go outside and open the bay door where my air line attached, there was 2 on/off handles, open them one at a time (after 7am) and let the air out until the water is gone, then do the other...hold your hand about 18 inches in front, you'll feel the water, then dry air (your manual will have the info)! You should do it each morning before you depart.  If I had to leave during quiet time at park, then I would leave and pull over ASAP and do it...sounds like a jet engine at take off..:wacko:

Other coaches, like my current one, will dump air automatically out the rear, each time I start coach! :)

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rfsod48   

In checking my manual, my coach also automatically dumps air when I start, so I guess I am ok as far as air tanks.

Again thanks all for the info

Roland

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wolfe10   

No, the purging you hear when "cut-out PSI" is reached is just the air dryer purging/cycling.

Nothing to do with tank drains. Yes, some chassis/coaches are also equipped with automatic tank purge valves.

CHECK WITH YOUR COACH MAKER TO SEE LOCATION AND TYPE OF TANKS DRAINS ARE ON YOUR COACH.

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wolfe10   

This from a PM I sent to Roland in reply to his PM:

 

Check with your coach maker to find out where your tank drains are.  Couple of popular choices:

Air line lead from tank to an easy to access place with valve where it is easy to get to.

Some tanks have automatic valves-- good for expelling contaminants, bad for evaluating status of air dryer.

Some drains are just on the tanks themselves.

Most are just 90 degree valves and require no tools.

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