Heated Holding Tanks

BobLandry

Senior Member
Joined
Jan 8, 2011
Messages
2,495
How do the tank heaters work? I have not found any type of switch or control for them.
 
Heated underbelly and heated tanks are different. Heated underbelly uses furnace to heat tanks. Tank heaters have a switch on main control panel and you turn it on, the tanks have 12v heating pads with built in thermostat control. If you have tank heaters, it's a single switch for all tanks combined.

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How do the tank heaters work? I have not found any type of switch or control for them.

Hi Bob,

If you don’t have the tank heater switch, you don’t have electric tank heaters.

Sorry...


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Yeah, if you have a tan exterior Reflection, you don't have them. Switch is in the control panel.
 
... but don't worry. The fresh and waste tanks are the last things to freeze due to their mass when they have something in them. Your outside hose, the internal water lines and pump will freeze way before the tanks. If you're using the unit and it isn't winterized, just keep the furnace set to keep the basement above freezing.

Rob
 
I was just wondering as the lists of packages that come standard says it has heated tanks. I guess specs are subject to change..
 
I was just wondering as the lists of packages that come standard says it has heated tanks. I guess specs are subject to change..

Again, depends when it was built....if you own a tan exterior one, the packages were different than they are now. Do you have auto leveling?
 
Again, depends when it was built....if you own a tan exterior one, the packages were different than they are now. Do you have auto leveling?

Hi Steve, his sig says he has a 2021.


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Hi Steve, his sig says he has a 2021.


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That doesn't mean anything. There was tan exterior 2021's and there was white exterior 2021's.

The white ones all have auto leveling and tank heaters. Tan do not.
 
Our Imagine has water pump inside cargo area. I have taken a quartz work light and put inside cargo area when temperatures drop below about 25; it will keep pump and water lines from freezing. Also let furnace run to heat under belly.
 
That doesn't mean anything. There was tan exterior 2021's and there was white exterior 2021's.

The white ones all have auto leveling and tank heaters. Tan do not.

Thanks, I thought they stopped making tan models in 2018. Old dog just learned a new trick.


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My 2021 337RLS has tank heaters with switch. My question is. How do you know that they work? That area is all covered up.


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My 2021 337RLS has tank heaters with switch. My question is. How do you know that they work? That area is all covered up.


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I don't have a tank heater, but since they are electric you could unplug shore power and try them. The energy the battery is putting out should spike a bit. This is assuming you have some type of battery monitor. If you have a fancy surge suppressor you may be able to tell when plugged in. Some electrician might have a better idea or explanation.
 
My 2021 337RLS has tank heaters with switch. My question is. How do you know that they work? That area is all covered up.


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You don't know, really - you have to trust. On the other hand, the tanks freezing is the last thing you have to worry about in cold weather. The water lines (especially the ones to the kitchen island in the 337), the water pump, etc. are your main concerns. Due to the mass of liquid in the tanks, it takes a lot longer at lower temperature for them to freeze. We wintered last winter at the top of the Chesapeake Bay in Maryland. We had several winter storms with up to 6" of snow and a few nights in the teens... I may have turned the tank heaters on a night or two when the winds were blowing.

Rob
 
I'll unplug and watch my victron to awe if it spikes. Thanks guys.

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I'll unplug and watch my victron to awe if it spikes. Thanks guys.

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OK, something else just occurred to me. Is there a thermostat built in to the tank heaters that will only turn on if the switch is On and the temp is below a certain point? If so, watching for a electrical usage spike won't work.
 
OK, something else just occurred to me. Is there a thermostat built in to the tank heaters that will only turn on if the switch is On and the temp is below a certain point? If so, watching for a electrical usage spike won't work.

Don’t think so. Once you flip the switch they are on.
 
My 2021 337RLS has tank heaters with switch. My question is. How do you know that they work? That area is all covered up.


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I have a battery monitor and these are my limited observations. In my 2018 Solitude (maybe different from your setup), each tank heater draws about 5 amps from the 12V when on. When cold enough with the (1) black, (2) grey and (1) fresh water tank heaters on it is about 19A draw. In my trailer, each tank is on both a rocker switch (on the convenience center) and a thermal switch (although Grand Design told me there was no thermal switch). The thermal switch looks like it turns on/off around 45 degrees, but that is a very rough estimate. In cold weather (in the low 20F), they will stay on continuously. Above mid-40s they are off (no current draw) even if the rocker switch is "on". Between those temperatures the heaters cycle on on off. I have only camped a few times when it stayed cold enough to test, so these are very rough observations. If it is warm during the day (50s) even getting down around 30F is not enough to turn the heaters on. Again, the furnace will heat the under frame area and there is a lot of thermal mass there.

Hope this helps

Chris
 
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