Fresh water holding tank heat?

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jesheba

Active member
Joined
Jan 29, 2007
Posts
27
Any ideas to keep my fresh water tank protected from below freezing temps? My tank is accessable though the front storage area.It sits on a sub-floor under the bedroom.I don't believe I can use those heating pads (ultra-heat etc.) since I can't get to the bottom and if I could they would get crushed.I have been told they would not do much sitting on top.Of this I'm not sure?I would be using the 5th wheel in the fall into early December here in northern Illinois.Nights can often fall into the teens or 20's.Any advice would be much appreciated.I'm new at this!
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Is your tank exposed/subjected to the heating of your furnance in the interior of your tralier?  If so, you should have no problems as long as your furnace is working.    Water approaching freezing at around 37?F lightens and rises upwards.  If it the upper part of the tank is exposed to the heat of your furnance it will be warmed and sink.  The resulting convection should hold freezing off well down into the 20s.  Tough on the propane bill tho.
 

jesheba

Active member
Joined
Jan 29, 2007
Posts
27
There is duct work going through this area and I believe it might be enough to with stand freezing.However I will be leaving the trailer alone 4 days aweek.My plan was to use some sort of auxillary heat to keep it warm.For example I purchased an enpure heater(halogen heat) and an oil radiator heater to maintain a warm interior.So far this has worked in some pretty cold weather.This of course will not help the compartment where the water tank resides.Those heating pads sound great but I don't have access to the bottom.I just wonder if I put it on top of the tank and insulated around it if it might still work? Maybe a light bulb? Thanks for your reply!!
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
74,369
Location
At our Silver Springs FL home
Light bulbs in/around pipes and water sources are a pretty common solution to heating a small area. I have a 75W light bulb burning in the bay with my water pump & valves tonight, when temps are expected down to the low 20's. Depending on how large the area is, 60-150W of light bulbs (multiple smaller bulbs are OK) might work well for you.

Your main problem is actually the piping from the tank to the pump and faucets, where water is trapped between closed valves. That water has no place to go when it expands, so it breaks things. Water in the tank can generally expand OK without breaking anything (assuming tank is less than full), though there is no guarantee. Heating the trailer and the storage areas where the pipes run is the best solution.
 

WILDinTHEwoods

Well-known member
Joined
Jan 15, 2007
Posts
59
Location
Cannonfalls Campground, Minnesota
What temperature do you plan on keeping the cabin of the RV at while you are away.  If you aren't going to leave the heat on at all during the 4 days that you are gone your problem is going to be the water lines not the tank.  The lines are 1/2 inch and the holding tank is approximately 2 feet by 3 feet by 4 feet.  Even if only half full it is going to take alot more to freeze that mass of water.  The holding tank heater you are referring to is for RV's with the holding tank mounted to the bottom of the camper just like your grey and black water tanks.  So they are OUTSIDE.  Your fresh water tank is inside.  So, unless you plan on winterizing your camper every time you leave you will have to keep the heat on.  If your going to set the temp for 40 or 50 degrees you could leave the access panel to the holding tank open so that the warmed air can circulate into the area where the tank is at.
 

John From Detroit

Well-known member
Joined
Apr 12, 2005
Posts
25,114
Location
Davison Michigan
In my rig the water tank is "off the floor" of the compartment, about 3 or 4 inches I think w/o measuring.  I strung a string of C-9 (outdoor) christmas lights under it, about 150 watts,  These are then plugged into a "Freeze-Plug" device I got at Lowes.  (Thermostatic outlet) which turns the lights on between 35 and 40 degrees.  Adds about 10 degrees to my low temp limit (or rather lowers the limit about 10 degrees)

I use traditional 75-100 watt bulbs in other "wet" compartmtnes (Any compartment with pipes or tanks in or above it)
 

NCHornet

Member
Joined
Jan 30, 2007
Posts
12
I would apply the heating pad to as much of the tank as possible and then stuff R30 insulation all around the area and you should be fine.
 

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