Engine Boost Solenoid (Contactor)

[PIPEWRENCHGRIP]

This is in response to Thomas Felch tech topics article in the December FMC magazine. I know this problem has been talked about before, but I will give my experiences with it. The Trombeta battery boost solenoid has more than on purpose. It can be activated by a swich on the dash to start the engine in case the engine battery voltage is too low to start the engine. I have even used it to start the generator when my house batteries were down.

The other purpose is to maintain a charge in all the batteries. When the engine is running, not connected to shore power it will pull in to charge the house batteries. If you are plugged into shore power it will pull in to charge the engine battery. This is controlled by the BATTERY MAINTAINER (ISOLATOR RELAY) Mine is located in the front driver side compartment.

I have found that when the boost relay was hot it was on all the time because the contacts in the relay were corroded. I found that out by checking the voltage on both hot lugs on the relay while it was pulled in. The voltage was different, that told me that the problem was inside the relay. I took the relay out and did a little surgery on it. I cleaned the contacts, reassembled it and a year later I had the same proglem so I installed a new one. A year later the same problem. Then I read an article on this Forum learned of another relay with different metal contacts. I purchased one these and it's been working fine ever since. While it's pulled in it's hot (normal). When the batteries are all charged up it drops out and is cool.

The model I got is a Trombetta 114-1211-020. I think the old one was 114-1211-010, just one number different. I have a 09 Monaco Diplomat, the Holiday Rambler may have the same set up.

[dickandlois]

Bill, some good information! Always good to have options.

After looking up the item for more information on Trombella. They have both intermittent and continuous duty stiles with both Grounded and ungrounded series.

The price on there relays is not bad and they use a silver alloy for the contacts, with a good current rating. The Item you listed is in there Bear series.

A link for others who might be interested:

http://shopping.murcal.com/Catalog/Bear-DC-Contactor-Family/114-1211-020

Rich.

[hermanmullins]

You never get too old to learn. After having my coach serviced the shop owner told me that my coach batteries were down. He said that he used the boost and it started. I told him I didn't think is was worked. That was when I learned that you need to hold the boost in for 10 to 15 seconds before trying to start. Guess what, when I held down the switch as he had directed the engine started. DUH, old man.

Herman

[ClayL]

The 20 suffix designates silver contacts. I bought that one (Bear Series) and had to send it back and go with the original part type because where mine is mounted is too small and cramped to install it.