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cti2000 · 06-29-2018, 02:59 PM

My question involves the Precision Circuits power control system (PCS). Last weekend we were are a location that only had 30 amp service. When plugged in to the 30 amp power pole I was not able to change the service type to 30 amp service on the PCS monitor panel. The panel showed 50 amp power service. The set button would not change service type (such as 20 amp or 30 amp). Cycling through the different screens on the monitor, the Line Status screen showed a voltage reading of 119 volts on L1 and 8 volts on L2. Continuing on to the Wiring Status screen no errors were shown. I checked the campground power before plugging in and it checked OK. The usual check..120v hot to ground, 120v hot to neutral and 0v ground to neutral.

When I returned home I plugged into 50 amp service I have at home. This time the PCS monitor Service Type screen correctly showed 50 amp service. The Line Status screen showed 123 volts on L1 and 8 volts on L2. Wiring Status screen shows no errors. I also checked the power receptacle here at home and it checks OK. So I checked the voltage on both line 1 & 2 from the house receptacle through the transfer switch and at the breaker in the panel located in the half bath. Both legs 123 volts all the way to the breaker. I believe the PCS monitor gets the voltage reading form the current sensor cups that are located inside the breaker box. So my thinking is the module that reads and communicates voltage inside the breaker box is defective.

If an effort to reboot everything, I unplugged the coach and turned off the house batteries. Checked the connection of the data cable to the PCS monitor. Powered everything up and still have 8 volts reading on L2. Has anyone seen this before?

Soppy · 06-29-2018, 03:13 PM

It is possible the module is defective . Check the wiring from the module to the panel. There may be a fuse in line that is blown. When plugged into 30 amp L1 & L2 are connected together so the voltage should be the same on both legs.

twinboat · 06-29-2018, 03:22 PM

Have you switched off any breakers in the panel ?

Some folks switch off the washer breaker, figuring they don't need it on, and discover that the voltage sense wire is connected to it.

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Winepress · 06-29-2018, 04:02 PM

Sounds like a sensing module is bad. PC is very good with support, I would give them a call.

ptw · 06-29-2018, 06:54 PM

As Twinboat mentioned, I turned the breakers off for electric heat today and one of the legs went to 8 volts while plugged into a 120 V outlet.

Winepress · 06-29-2018, 07:19 PM

The sensing modules should be on incoming L1 and L2. If any sensor is on a individual circuit breaker, it’s wired incorrectly.

When I first took delivery of my DS, I had it about a week when the Oasis heater element shorted out. When it went the breaker popped, but the spike took out the PCM system on L1. The PCM showed incorrect readings which caused the whole system to shed loads. No AC or cooktop as the PCM system said I was drawing 180 amps @ 8 volts.
Called PC and they had me pull the 12v fuse controlling the system, everything was fine until I could get it back to the dealer.

ptw · 06-29-2018, 07:31 PM

Quote:

Originally Posted by Winepress

The sensing modules should be on incoming L1 and L2. If any sensor is on a individual circuit breaker, it’s wired incorrectly.

When I first took delivery of my DS, I had it about a week when the Oasis heater element shorted out.

It seems that the ideal location would be the incoming lines. Doesn't sound like Newmar is doing it that way if your 2018 was wired to the Oasis heater and my 2017 is wired to the Oasis heater. The other voltage pickup comes from a different load side breaker. I don't recall which one it is on mine.

Winepress · 06-29-2018, 07:36 PM

Quote:

Originally Posted by ptw

It seems that the ideal location would be the incoming lines. Doesn't sound like Newmar is doing it that way if your 2018 was wired to the Oasis heater and my 2017 is wired to the Oasis heater. The other voltage pickup comes from a different load side breaker. I don't recall which one it is on mine.

Mine are on the incoming L1 and L2. If they are not, you’re not going to see correct current, not so much an issue on 50 amp, but could be a real issue on 30 or lower amp.

twinboat · 06-29-2018, 07:59 PM

The current sensors must and will be on the incoming lines.

Its the load sharing signal wires, to the controller, that are often on breakers. If they read 240 volts there is no sheading. If they read 0 volts because you are on 30 or less amps, the sheading system is enabled.

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cti2000 · 06-29-2018, 08:27 PM

[QUOTE=twinboat;4265351]Have you switched off any breakers in the panel ?

Some folks switch off the washer breaker, figuring they don't need it on, and discover that the voltage sense wire is connected to it.

We have a winner...well sort of. I did switch some breakers off because I had the grandkids with me and they are switch happy.

When I originally looked at this I removed all power and cycled the main breakers. Tonight after reading the reply from twinboat, I switched the breakers I tuned off because I thought they were not needed. Tuned them on one at a time and watched the monitor panel as I did this. None of them restored the reading on leg 2 to normal. Finally, I cycled the main breakers and sub panel breaker (for the PCS controlled loads) and now have 123 volts on both legs. So I think the main breaker may be weak. If this happens again I'll replace the main breaker.

I also sent an email to Newmar about this and was presently surprised to get a call from them 20 minutes later. Thanks to all who answered.

ptw · 06-29-2018, 08:28 PM

I was talking about the voltage pick up, not the current sensor. The OP said he had 8 volts on L2. Just saying he should check that none of the breakers are tripped or turned off in his panel.