A caution on the Precision Plex holding tank and elbow heater system

[NXR]

It's going to get into the mid to low 30's so I went to turn the Tank Heaters on using the Precision Plex touchscreen. The touchscreen is displaying this message:

Tank Heater Enabled, will turn on if voltage > 13.2 V

Unfortunately the Precision Plex touchscreen is displaying its usual 13.1 VDC reading on the "Levels" screen. The Xantrex inverter panel above the touchscreen says the house battery voltage is 13.0 volt.

I sent an email to the support address for Precision Circuits and they responded with their usual almost immediate response. Excerpts:


I presume the 13.1 VDC reading means that if it had gotten down to freezing last night that the tank and elbow heaters would not have powered up.
Correct


Is there a way to decrease the minimum house battery voltage needed before the tank heaters will turn on?
No

The Voltage was not selected to ensure the batteries did not go flat. It was selected to only allow operation when RV was plugged in and charging.

As far as I know, minimum charging voltage should be 13.3V. So that is the reason for our 13.2V threshold. Again, you may want to check with the Battery Charger company.


The root problem is there is a mis-match between how the Precision Plex Tank Heater system is programmed and how the Progressive Dynamics PD9270 Converter/Charger is programmed.

The PD9270 is designed to go into "Storage" mode if there has been no significant battery usage in the past 30 hours. The "Storage" mode voltage is 13.2 VDC, not the 13.3 VDC that Precision Circuits believes is the minimum.

The PD9270 manual: https://www.progressivedyn.com/wp-co...1F-english.pdf

The attached pictures are from that manual.

The only workaround I can think of is to shut off the shore power breaker and draw down the house batteries for a while, although I have no idea what "no significant battery usage" means to Progressive Dynamics. That should take the charger out of Storage mode for the next 30 hours.

I'm asking our dealer to open a warranty ticket with Forest River but I think Ohio will freeze over before any fix is issued.

Ray


PS: I also asked this question since it's a related topic:

Will turning the on the Tank Heater damage anything if the "Warning: Low Water Level" message is being displayed? Is the tank heater inhibited if that tank level is too low, are all tank heaters inhibited, or is it just an advisory message?

Not sure, we do it differently for different RV’s but if it turns on it should give you that feedback.

Yes, if there is no water, and Tank Heater is turned on, depending on Heater strength and actual air temp, there could be damage.

[NXR]

OK, I took the easy way out. I shut off the shore power breaker and took the dogs for a 35 minute walk while leaving lights and the inverter on. The house batteries were down to 12.1 VDC when I flipped the shore power breaker on and now the touchscreen is showing the hoped-for 13.6 VDC and slowly climbing.

I probably could have just shut the shore power off and also shut the house batteries off for a much shorter period of time to drop the power to the converter/charger and done the same thing. That will be the next experiment.

Tonight is the only night it’s getting that cold.

Ray

[H3OHIO]

Wow that's interesting! I guess I'm glad I don't have a touchscreen to control everything, just old-fashioned on/off switches on our 2019 XL369. With all the LED lighting they install in these new RV's my converter very rarely kicks into charging mode, It mostly stays in maintaining at 13.1-13.2 volts. I can see how what your saying could be an issue, sounds like they need to do some reprograming of there control software...

[NXR]

Agreed. I asked the Precision Circuits support person to try and get this issue addressed with Forest River. Today is the first work day since I found the problem so obviously I do not have an update on that yet, and today is a holiday for some companies.

Right on schedule, the PD9270 converter/charger kicked back into Storage Mode just after midnight. It was only supposed to go down to 40 last night so I wasn't worried about freezing, plus I had turned the tank heaters on earlier in the evening to build up some heat in the water mass.

While the house battery voltage was at 13.1 VDC when we awoke this morning, interestingly, the touchscreen indicated that the tank heaters were turned on and the Tank Heater screen message said voltage was 13.5 VDC when the voltage clearly was lower. It looks like that is a static message that does not change once the heaters fire up.

I turned the Tank Heater off and back on and now the message says they will turn on when the voltage gets greater than 13.2 VDC. So hopefully this means that the voltage check is only done when the Tank Heater function is selected to On and only a factor until the battery voltage rises.

The other possibility is that the Precision Circuits controller does cut the tank heaters off if the voltage drops but the touchscreen message does not reflect that change. If that is the case then someone could get fooled into thinking they were protected when they are not. Based on one email response, I do not believe that is the way the system works but I am not certain.

UPDATE: Since it's going down to 35 tonight and since the PD9270 is in Storage Mode and showing 13.1 VDC on the Precision Plex touchscreen, I just killed the shore power to the coach and shut the house batteries off for one minute instead of trying to draw the battery voltage down by running stuff. Yes, the PD9270 converter/charger did reset and the touchscreen now shows the house batteries are at 13.5 VDC and the Tank Heater screen confirms that the heaters will turn on.

There does not appear to be any way to disable Storage Mode manually, even with their optional remote pendant, but this method does work. As long as I remember about the need to do it.

Ray

[NXR]

I was asked privately to simplify this.

• While the tank heaters themselves are controlled by thermostats integral to the heating pads, the power to them is controlled by the Precision Plex touchscreen computer system. The computer will not actually supply power to the heater thermostats until the house batteries show 13.3 VDC or higher on the Precision Plex "Levels" screen.
  
  
• The Progressive Dynamics DC Converter has a Storage Mode where they drop the voltage to 13.2 VDC if the house batteries have not been used in the last thirty hours. Like when you're plugged into shore power for more than 30 hours.
  
  
• Precision Circuits, the manufacturer of the Precision Plex system, told me that as far as they know, the house batteries should be at or above 13.3 VDC when charging. They selected that voltage to assure that the RV is not solely running on batteries due to the power draw of the heaters.
  
  
• If the Precision Plex system says they will turn the heaters on when the voltage goes "> 13.2 VDC" believe it. You'll need to turn off all power to the RV for about one minute, which removes power from the Converter and takes it out of Storage Mode.
  
  
• Precision Circuits told me there is no way for the end user to adjust that 13.3 VDC threshold. I suspect it will require reprogramming by them.
  
  
• After restoring power you'll see the Precision Plex system is showing a higher voltage and if you switch the tank heaters on, the touchscreen will show that they are on instead of displaying that warning message.

HTH,

Ray

[NXR]

On another thread regarding whether the Georgetown chassis battery is charged off of shore power or not, it looks like this programming incompatibility may be affecting the Precision Circuits Battery Control Center as well.

The Summary section of this post has the essentials: http://www.forestriverforums.com/for...ml#post2222671

FWIW,

Ray

[TitanMike]

Originally Posted by NXR

I was asked privately to simplify this.
[LIST][*]While the tank heaters themselves are controlled by thermostats integral to the heating pads, the power to them is controlled by the Precision Plex touchscreen computer system. The computer will not actually supply power to the heater thermostats until the house batteries show 13.3 VDC or higher on the Precision Plex "Levels" screen.

Have you considered just installing a bypass switch so you can select a power source for the heaters manually when connected to Shore power? A Single Pole-Double Pole switch would allow a single wire transfer of the power source from touchscreen to battery direct.

Just label it "Tank Heater - Auto/Manual". Let the Auto mode control the heaters while driving down the road and batteries are receiving power from the alternator.

I have a similar switch for my tank heaters. It's labeled On/Off but no touchscreen

[BigRockr]

Get the Remote Pendant for the PD9270 and just put it in Boost, 14.4V.

[NXR]

Originally Posted by TitanMike

Have you considered just installing a bypass switch so you can select a power source for the heaters manually when connected to Shore power? A Single Pole-Double Pole switch would allow a single wire transfer of the power source from touchscreen to battery direct.

Just label it "Tank Heater - Auto/Manual". Let the Auto mode control the heaters while driving down the road and batteries are receiving power from the alternator.

I have a similar switch for my tank heaters. It's labeled On/Off but no touchscreen

I'd have to dig into the Precision Plex Master panel and locate the relay. I can hear it click so that part wouldn't be difficult but I'm under warranty until July and I don't want any finger-pointing before the warranty expires.

This needs a firmware fix to do it correctly for everyone with this combination of equipment.

Ray

[NXR]

Originally Posted by BigRockr

Get the Remote Pendant for the PD9270 and just put it in Boost, 14.4V.

I had considered that but it doesn't remedy the concern with over-charging the batteries a bit.

The tank heater problem wss reported to FR by the dealer so I'll have them do another report for the BCC, unless one fix does the trick.

Ray

[Dodge Guy]

13.2V? Wow, they don't give you much room. The minimum should be around 12.5 since that is normal unpowered voltage. Heck even 12.2V would be a good shut off point. Sounds like they need to offer a low voltage set point for various users as some don't plug in and other do.

[NXR]

Originally Posted by Dodge Guy

13.2V? Wow, they don't give you much room. The minimum should be around 12.5 since that is normal unpowered voltage. Heck even 12.2V would be a good shut off point. Sounds like they need to offer a low voltage set point for various users as some don't plug in and other do.

The Precision Circuits person said they needed to assure that shore power was available or a generator was running and they build stuff for a lot of manufacturers so they're by no means inexperienced.

My guess is that Forest River changed the converter after the initial design and no one noticed the problem. Since it doesn't show up until after 30 hours of shore power I can easily see that.

Ray

[bclemens]

FYI...there is a work-around that was apparently emailed out. (I asked to be included, just for curiosity sake)

"In the Utilities screen -> Tank Heater, while the Tank Heater is displaying “Disabled”, if you Press and Hold the button for 6 seconds, the Tank Heater will turn on and display “Manual Override”.
It will stay on until you turn it off, regardless of battery voltage. The owner is at their own risk of damaging the batteries, but they can prevent freezing if Progressive is sleeping."

I would say, if you are plugged in, this would work just fine.

[NXR]

Originally Posted by bclemens

FYI...there is a work-around that was apparently emailed out. (I asked to be included, just for curiosity sake)

"In the Utilities screen -> Tank Heater, while the Tank Heater is displaying “Disabled”, if you Press and Hold the button for 6 seconds, the Tank Heater will turn on and display “Manual Override”.
It will stay on until you turn it off, regardless of battery voltage. The owner is at their own risk of damaging the batteries, but they can prevent freezing if Progressive is sleeping."

I would say, if you are plugged in, this would work just fine.

Rats. That apparently does not work on the Georgetown's. I held the button when it showed Disabled and it changed to Enabled with the voltage note (and the level note). The blue border on the button remained present until I lifted my finger. I held it all the way to one minute in varying intervals but no joy. The batteries are showing 13.0 VDC right now.

The fellow from Precision Circuits told me that the level caution is just a warning and does not lock the system out. If it really is a lock-out that would be the difference.

Thanks for the follow-up,

Ray

[bclemens]

that came from the head guy....so I guess we will see what they say now.

[CMcDonough]

Here is a link from Precision Circuits that shows the manual override:
https://youtu.be/fHb-vIbknBw
This does in fact work on Georgetowns as I just tested it on several units. Hopefully this helps.

Chris

[NXR]

I see your video and raise you my 23-second video showing that not all Georgetown's are created equal.

https://1drv.ms/v/s!AhltgE5N10kVgQPm...wfm4w?e=arlp8q

The difference is that my voltage is below the minimum to enable the tank heaters while in the Precision Plex video they are above the minimum voltage to start.

EDIT: I turned the Converter circuit breaker off for ten minutes to reset it. When I turned the breaker on the output voltage from the Converter was 14.0 VDC. While the tank heaters will now turn on normally, the manual override process still does not work.

Methinks it's a firmware version issue.

Touch the Settings gear in the upper left corner. Make sure Time is selected. Touch the word Settings at the top center of the touchscreen.

Ray