Chassis and a Domestic Solenoids

[barmcd]

The solenoid that controls power to my domestic systems failed this week so none of the 12V systems like lights would work. The chassis side worked fine. Luckily I had a spare on hand. Troubleshooting was pretty easy. With the chassis and domestic switches on, and the 12 V Cut-off switch by the door turned on, I had 12V to the input side of both solenoids, but only the chassis solenoid had 12V on the output side. I made a jumper to tie the in- and output sides together and the lights worked. The replacement solenoid is a White Rogers 70-111224 12V Continuous Duty solenoid with a 400 amp inrush and 60 amps continuous current capability.

Old on top new on bottom. Those with a keen eye will notice a purple jumper on the old solenoid and a red on the new. I had to make a new jumper from the chassis to the domestic solenoid because the original was too short with the new solenoid. It’s got a little different shape and the mount is a little higher making the terminals a little farther apart.

[Timaz]

Mine is still working but I do have a spare when it does die.

[Jeff753]

As you point out one feeds the front run bay and the other feeds the house fuse block. I’ve replaced them before too. It’s somewhat of a poor design to be continuously engaged but a cheap part. Some have simply eliminated them.

[barmcd]

Originally Posted by Jeff753

As you point out one feeds the front run bay and the other feeds the house fuse block. I’ve replaced them before too. It’s somewhat of a poor design to be continuously engaged but a cheap part. Some have simply eliminated them.

Talk about irony, if you eliminate them, you lose the ability to easily disconnect power from the chassis or domestic circuits. You need to do that when you replace things like these solenoids!! Seriously, if I jump around them all I lose is the front battery disconnect switch right?

[JJTL]

Originally Posted by barmcd

Talk about irony, if you eliminate them, you lose the ability to easily disconnect power from the chassis or domestic circuits. You need to do that when you replace things like these solenoids!! Seriously, if I jump around them all I lose is the front battery disconnect switch right?

The solenoids are controlled by the "Battery Cutoff" or "Salesmen Switch", but there should also be a mechanical "Battery Disconnect" close to the batteries.

The Salesman Switch/Battery Cutoff turns off 12V power to most items, however, I believe it does keep power on to some systems like propane/CO alarms, as an example. Where as the mechanical disconnect switch located near the battery is a physical disconnect of all 12V straight from the battery bank source.

If your Dynasty is the same as our Sig, then you are correct that by-passing the solenoids you should only lose the Salesman switch function.

As an aside, whenever doing work on the 12V electrical system one should use the main battery disconnect to remove power, and not just rely on the Salesman Switch/Battery Cuttoff solenoids, for reasons described above.

P.S. Thanks for sharing the White Rodgers part number! I have a Napa part number currently. We too have had an intermittent solenoid, and so its actually on the list to replace. Seems to be a very common problem.

[Outbound]

I thought solenoid should be 80 amp continuous duty.

[lwmcguire]

Originally Posted by Outbound

I thought solenoid should be 80 amp continuous duty.

My Trombetta relay was 200 amp continuous on the Tuscany

[barmcd]

Originally Posted by Outbound

I thought solenoid should be 80 amp continuous duty.

I don't know for sure. A search of the part number on the old solenoid doesn't come up a specific replacement and apparently Echlin doesn't make this part any longer. This White Rogers part number shows up in the search. The part number in my owners manual is not the same as the Echlin part number on the solenoid, but the part number in the manual crosses to this White Rogers part number.

Total potential draw in the 12V fuse box is 244 amps -- the great majority is for lighting. My coach only utilizes 160 amps of that 244 because I don't have some of the options installed. The only other items that use 12V are the water pump, the kitchen fan, the bath fans, the cook top, and the furnace. I'd be hard pressed to exceed 60 amps of current since I've replaced most of my incandescent lights with LEDs and I no longer have a propane cooktop.

[barmcd]

Originally Posted by lwmcguire

My Trombetta relay was 200 amp continuous on the Tuscany

I believe that solenoid serves a different function in your coach than these do in mine.

[JJTL]

The part number I had for the solenoid is: Napa Echlin "ECH ST85"

Here is the link for the part: https://www.napaonline.com/p/echst85

Although it is called a "starter" solenoid, it is rated for 80A continuous duty.

[HJLowell]

I got rid of mine many years ago.
I use the house or chassis batery disconect switch, as suggested above also, if I want to work on the DC.
Or change out batteries.
DC flows both ways [emoji106]

Originally Posted by barmcd

Talk about irony, if you eliminate them, you lose the ability to easily disconnect power from the chassis or domestic circuits. You need to do that when you replace things like these solenoids!! Seriously, if I jump around them all I lose is the front battery disconnect switch right?

[barmcd]

The white rogers 80 amp model is p/n 70 111224S1

Item - DC Power Solenoid
Coil Voltage - DC 12
Amps - 80
Coil Type - Isolated
Contact Form - SPNO
Coil Termination - #10-32 UNF-2A Thread
Contact Termination - 5/16-24 UNF-2A Thread
Contact Material - Copper
Duty Cycle - Continuous
Mounting Base - Std. Bracket
Series 70
Enclosure Dust Resistant
Standards UL 538 Recognized