Lost all AC (electrical) service

[bobmoore1954]

For no apparent reason (nothing was running) we lost all AC electrical service this morning. Checked the Magnum panel and there's a fault with the message 'Internal NTC'. Bought our coach 2 weeks ago, new. It's a Ventana 3709.

Called Newmar and tried to reset the inverter. They're still thinking about what else I might do.

Strange, even though we're plugged into shore power, there's no AC in the coach. Same when we run the generator - no AC.

Any ideas out there please?

[Hit_the_Rhod]

[QUOTE=bobmoore1954;3761297]For no apparent reason (nothing was running) we lost all AC electrical service this morning. Checked the Magnum panel and there's a fault with the message 'Internal NTC'. Bought our coach 2 weeks ago, new. It's a Ventana 3709.

Called Newmar and tried to reset the inverter. They're still thinking about what else I might do.

Strange, even though we're plugged into shore power, there's no AC in the coach. Same when we run the generator - no AC.

Any ideas out there please?

When you start the generator, do you hear the "thunk" from the transfer switch? If so, then the genny is providing AC power, but it is not getting to the distribution panel. I would hazard a guess that the wiring on the back of the main panel circuit breaker is not making contact. Turn off all power, and remove the panel, check all connections for tightness. Same goes for the transfer panel. Good luck!

[stang37]

Had the same type issue on my new Ventana. NO power from anything put no error message. Turned out the main fuse (350 amp) from the batteries had blown. This will not allow the inverter to work as it must have DC power to operate. Someone did not tighten the bolts from the batteries to the main fuse which is located in the battery compartment. Maybe your issue.

[bobmoore1954]

Yes, when connected to shore power, I hear a thunk out of the transfer switch. Also when connected to shore power, the Precision Controls unit detects that it's connected to 30 amp service.

[Ricci]

Hi - What it's telling you is that there was a large discrepancy in the values from the temperature probe on the batteries. That causes the inverter to shut down. Are the batteries hot or swollen? If not I'd assume that the sensor has gone bad. Make sure it is still on the batteries and not fallen off somewhere. If not the sensor then the inverter has gone south on you. That's why you have a warranty. Better now than later.

Tom

[Rvlegaleagle]

Hey Tom, just noticed....2018 DSDP 4369 On the Line 8/18....congratulations

[Ricci]

Thanks. Glad to leave the Bus and excited about the Dutch Star build.

Tom

[YC1]

Grab a voltmeter and check your batteries.

I suspect they are dead for some reason or there is an open fuse or loose connection.

Now before someone tells me this is DC hang in there.

You probably have an energy management system and it "sheds" AC items.

Ok but then the inverter if turned on would at least run some outlets. True, but if the batteries are now dead you lose that and the control of the EMS panel.

Turn off the big battery bank via the switch in the copartment.

Start the RV. Hopefully it does start. Let it run a couple of minutes. Now measure the battery voltages. If the house bank is low then push the emergency start button on the dash area to see if the voltage starts to rise quickly.

If it does NOT, and the house batteries are not charging up then you may need to do an emergency bypass operation with a jumper cable.

IF you are NOT comfortable moving forward with this get someone that is.

Once both banks are around 13 volts, go ahead and start the generator or reconnect to shoreline. Do NOT remove that jumper because you still need the alternator filling the batteries.

If this makes the AC outlets run or the microwave lights up you will be getting close to the resolution.

These are complex systems but 12 volts is necessary for so many things to work.

Always attack the "obvious" first.

Heck, who knows. These snow flakes are so different and yet similar in many ways.

[bobmoore1954]

I'll check the batteries when I get back to the coach, but the Magnum panel said they were at 12.8-volts.

It acts like the inverter is 'dead'. It will not invert DC to AC. When connected to shore power, it will not pass AC nor will it charge the batteries.

The coach is receiving AC from the generator or shore power, because the air conditioning units will run.

Here's what I've done. I'm concerned about all the food in the refrigerator spoiling and that I won't be able to get the slides in if the batteries drain down too far.

Regarding the refrigerator, it plugs into a convenient outlet beneath the booth. I took the dinette booth slide compartment out and found it. So I plugged the refrigerator into a heavy duty extension cord and ran it out through the bedroom emergency window to the AC pedestal.

I found that the full slide and the kitchen slide would retract with the Diesel engine running, it the bedroom slide would not. So I brought the bedroom slide in. I left the other slides out believing if I need to I can start the Diesel engine and depress the battery booster, to get enough to retract them later.

No solutions yet, but I learned that Newmar customer service does answer the phone on Sunday morning.

[bobmoore1954]

Originally Posted by stang37

Had the same type issue on my new Ventana. NO power from anything put no error message. Turned out the main fuse (350 amp) from the batteries had blown. This will not allow the inverter to work as it must have DC power to operate. Someone did not tighten the bolts from the batteries to the main fuse which is located in the battery compartment. Maybe your issue.

I'll check this...is the fuse on the wall of the battery compartment?

[bobmoore1954]

Originally Posted by bobmoore1954

I'll check this...is the fuse on the wall of the battery compartment?

The Magnum panel is reporting 12.8-volts 0-Amps. I'm wondering where it measures the voltage, upstream or downstream of the battery fuse? If it measures after the fuse, it's probably not a blown fuse?

[YC1]

Your first post said no AC.

Then a later post said you have air conditioners running? From generator and shoreline?

If the converter is broken and not charging your batteries will go dead of course.

Once again, start at the batteries with a voltmeter. Measure both banks and write it down. Then start the engine and measure again. Those measurements will give a better picture.

[stang37]

Yes, There are two fuse blocks on the right side of the battery compartment. You will need a multi meter to check the fuses. Not recommended to jumper the fuse as it carries a lot of Amps.

[bobmoore1954]

Thanks all, I too a look and gave a wiggle test and the connections all seem tight.