MEP002A just stopped running

[Chainbreaker]

The only problem with a battle short, is what happens when you do lose oil pressure? Or it overheats? But yes, it can be handy, in a pinch. I only had to use Battle Short a few times, and we would check the set lots more often. I never understood why the 002 and 003 never had a battle short.

Yes there is some element of chance that if you elect to bypass a safety shutdown switch you could leave yourself open to an actual unmonitored failure if running on an extended basis. A chance that one has to weigh against the situation at hand whether its worth the risk to keep on running. However...now after your comment and thinking about it from a critical operational standpoint it is probably just as easy to jumper each switch independently and only bypassing the offending switch, after determining its only due to a defective switch and not an ACTUAL oil pressure or a high temperature condition. Doing it that way, you are preserving the integrity of the safety circuit to monitor the other operational switch. I have both S4/S5 switches stocked as spares and a spare generator to boot. So for me it just a matter of quick troubleshooting.

Again thanks for the safety circuit TB5-8 to TB5-9 jumpering troubleshooting tip, its a quick way to determine if "anything" in that circuit (loose/broken wire, switch, etc.) is causing a shut down condition.

 

[Light in the Dark]

So the new OPS arrived. It appears this is a straight threaded item (versus tapered thread)... so what do I need to do to ensure proper sealing? Special hydrocarbon resistant thread tape? Nothing but proper tightening spec? How about wiring the leads back up? On this switch are three positions (NC, NO, and C). NO and C both have terminals with screws (which makes sense as this is a NO configuration). I assume its a standard part that they drill holes on to clear the terminal spec for whatever it is they are assembling. Do I need to test for line voltage to determine which of the two units on the machine is hot?

Thanks

 

[Light in the Dark]

Actually they might have a slight taper to the threads.

 

[Light in the Dark]

So I've gotten a few minutes this morning to read through the TMs, and I don't see any notes regarding which wire goes onto which post on the switch. As the unit I am putting on this does not match what I took off (exactly), I am unsure of which post takes which lead. Does it matter?

 

[Triple Jim]

It doesn't matter which wire goes on which terminal. The switch connects the two together when it gets pressure.

 

[Light in the Dark]

It doesn't matter which wire goes on which terminal. The switch connects the two together when it gets pressure.

I didn't think it did, but I didn't want to short out anything on a brand new part because I was guessing. Thanks Jim.

 

[Chainbreaker]

TIP: Its often beneficial to take a look at the schematic; especially if unfamiliar or in doubt. If you find "S5" on the schematic you can see that the switch acts like a inline pressure activated jumper to the circuit (no polarity). Even if you aren't experienced using or understanding schematics the circuits depicted on this generator are pretty easy to follow. It really helps to get familiar with where all the components are in the schematic and where they connect to. Having an understanding of where the circuit connects and goes often leads you to better apply common sense to troubleshoot a problem. I bought a "D" size blow up of the schematic (eBay) and its nice during bad weather to be able to sit inside, cup of coffee in hand, and research something before going out to the genset to start troubleshooting.

 

[Guyfang]

I also believe the S-5 is marked, (or used to be) with a numeral 1 and 2. If you look at the schematic, it shows wire number P64D16 hooked to terminal number 1, and wire number P65D16 hooked to terminal 2.

TIP #2. The last two numbers, of a wire number, is the gauge of the wire. So the only real important part is the first three numbers/letters. Like P64D, or P65D.

Tip #3. If you have a problem reading a MEP-002A schematic, because the printed quality is rotten, look at the schematic for the MEP-003A. About the only difference is the number of preheaters. For that matter, the TM's on the whole, are about 99.99999999% the same, so it doesn't matter which ones you use.

Tip #3. The schematic that is attached to the control panel top, is to be take with a grain of salt. There are several mistakes on it. ALWAYS use the schematics from the book unless you just have no way to get at them. I used to beat my mechanics with chains if they went anywhere near a gen set without the TM's.