Community Forums

bandmbrown · 07-16-2012, 12:27 PM

The MH is currently being used on 50 amp. So, for the monthly start up of the diesel engine and generator should I unplug the shore power. Usually run the engine to general operating temp then run the generator under load for a while. But..not under shore power. Might unplug just to continue with my usual program

RickO · 07-16-2012, 12:31 PM

I think the general wisdom now is that it's good to exercise your generator as you're doing but it's better to just let the diesel motor sit rather than to fire it up monthly. I believe the rationale is that, the worst thing a diesel faces is a cold, dry start and doing this monthly causes more harm than good.

Best of luck

Rick

Mr_D · 07-16-2012, 12:34 PM

Cummins says not to bother starting the engine if you aren't going to drive the rig for at least 30 miles. Diesel engines don't warm up enough to help and in fact add to the corrosion problems if only idled. They need a load to come up to temp. Not sure what CAT says.

The generator needs a load to bring the coils up to a high enough temp to burn moisture off. I run the heat pumps, one set on cool, the other on heat. After about ½ hour I switch the settings around.

Dunner · 07-16-2012, 01:25 PM

If a diesel is run without driving it, the injectors don't get hot enough to burn off the deposits and can "coke" up. Cummins says to not idle for more than about 10 minutes without driving it. You can buy a device to set a high idle, but it's best not to run it at all.

bandmbrown · 07-16-2012, 02:35 PM

Thanks guys...just saved me some time and money.
Concerning the generator....plug or unplug...

Senior Chief · 07-16-2012, 02:55 PM

Quote:

Originally Posted by bandmbrown

Thanks guys...just saved me some time and money.
Concerning the generator....plug or unplug...

You can leave it plugged in, but turn off any big loads first- the generator will take precedence over shore power. Let the gennie warm up for a few minutes before adding the load (heater or AC) and when your hour is up, turn the load off a few minutes before shutting down.

Dutch Star Don · 07-16-2012, 03:01 PM

bandmbrown.....In theory, the transfer switch should default to either the generator or shore power (however yours is setup). Sometimes it can brain fart and not switch or not switch fast enough. It's not worth taking a chance and having one conflict with the other. Disconnect the shore power.

Starting the engine with the power cord connected can also cause some other issues. On mine, I notice that when I run the engine with the shore cord connected, I get an alternator light on the dash come on. There is a conflict there of the engine charging the batteries and the shore power charging the batteries. This could be caused by my Xantrex aftermarket charger that charges my engine batteries when on shore power, but again, it's not worth taking a chance.

Mr_D brings up a good point about exercising your generator. A lot of coaches have heat pump A/C units front and rear. Heat pump units default to heat pump and actually have to switch via solenoid to cooling. My rear unit didn't get enough exercise and that solenoid went bad. So running one as A/C and the other as a heat pump and then switching the two is a good idea.

bandmbrown · 07-16-2012, 07:53 PM

Thanks again...answered my questions.

Skip426 · 07-18-2012, 11:00 AM

the worst thing a diesel faces is a cold, dry start and doing this monthly causes more harm than good.

Best of luck

Rick[/QUOTE]
After multiple starter relay failures , I installed a 50's style start push button in the engine bay; I now use the switch to spin the engine, after oil changes to fill the filter, and to lube the motor prior to start up after storage. Cummins says to disconnect the fuel solinoid, and crank with the key, I though this would be easier , and it is .

Dunner · 07-18-2012, 11:03 AM

If it has a fuel shut-off relay/solenoid, you want to make sure it doesn't activate it.

FormerBoater · 07-18-2012, 04:10 PM

If you want to play it safe, unplug before you exercise the genny.

If you want to really do what is best for the engine, take it out for a nice 30 mile drive every week or so. It is a lot of fun! (did it today).

DaveS
1998 American Eagle 40EVS

szy · 07-18-2012, 05:21 PM

Better to leave it sit ( starts are hard on them --- period )

all you did was get it warm and it will still condensate water into the system

Let it sit , this start and run it is not the thing to do

figure it out

Mr_D · 07-18-2012, 05:26 PM

Quote:

Originally Posted by Senior Chief

You can leave it plugged in, but turn off any big loads first- the generator will take precedence over shore power. Let the gennie warm up for a few minutes before adding the load (heater or AC) and when your hour is up, turn the load off a few minutes before shutting down.

Save the transfer switch and unplug the rig first.

Mr_D · 07-18-2012, 05:31 PM

Quote:

Originally Posted by Dunner

You can buy a device to set a high idle, but it's best not to run it at all.

On our DSDP's all I need to do is turn on the cruise control and tap the set button. It's set up to hold the idle at 1,000 rpm or so.

Cummins says not to have it idle on low idle for over 5 min.