Fresh water heater - RV-Dreams Community Forum

DeeJee · RV-Dreams Family Member

Fresh water heater

Second Chance · RV-Dreams Family Member

Most folks leave the waste tanks (both grey and black) closed until they're full and need dumping, anyway. This ensures that you have enough liquid to flush out any solids or sediment in the tanks. This issue is not related to your hot water heater, though. As long as you have fresh water in the water heater, you're OK.

Rob

Terry and Jo · RV-Dreams Family Member

I'm presuming that you are in that site on a 'long-term' basis, not that it makes any difference to your question. We have been doing similar for 4 1/2 years now. I keep some water in the fresh water tank (FWT) but I also keep the valve closed on the grey tank (GT). I do that so that when I go to dump and flush the black tank (BT), I've then got water to do more flushing of the sewer line to the sewer.

We have a indoor/outdoor, remote sensor thermometer system with two remotes. One remote is kept outside and under a slide in the shade for outside temps and the other remote sensor is in the underbelly near the water manifold of the plumbing so I can keep an eye on the temps in the underbelly. If temps drop enough, then I either turn on an electric heater in the underbelly or just run the furnace, which also helps keep the underbelly warmer.

So far, we've been down to -6 degrees here in Colorado, but I've never seen the underbelly get below 37 or 38 degrees. Our DRV does have better insulating R-ratings, so I don't know how low your underbelly would get. However, our fresh water tank is not in the heated area, so the tank heater is turned on when it gets cold out. If you have separate switches for the various tanks, as we have, I don't understand why keeping the GT closed because of temperatures.

The only issue we have had with freezing was that when the outside temps get down to about zero degrees, the hot water line to the kitchen sink wants to freeze up. Nothing breaks, and we still have hot water in the bathroom, so it's not a big deal.

Terry

Bill and Linda · RV-Dreams Family Member

We always keep water in our fresh water tank. ‘Been too many places where the water goes off or some such problem, including once, contamination. We then use it from time to time regardless if for no other reason to make sure the pump is working.

As long as you have heat in the rig and the weather stays in the high / mid - 20’s at night AND you run the furnace some you should be fine. Most all rigs have the tanks sort of heated via the LP Gas furnace now. Remember at 32.1 degrees F the water won’t freeze so it doesn’t take much heat to keep the tanks above that basically golden number.

In the past I actually put a remote thermometer next to the tanks so I have a good idea what’s going on in the tank area. You may not be able to do that but I make the suggestion nonetheless. Even a 100 watt light bulb - real ones not CFLs - will make heat and is a way to keep the tanks a bit warm depending on your configuration.

We strongly recommend NOT leaving the grey and especially the black tank values open. Lots of water is required to flush them out so we fill and flush. Yes, more trouble in the short run but much less big trouble in the long.

Leaving the black open is asking for really big trouble. IMO, the grey as well but not the disaster leaving the black open can cause. (Leaving the grey open will cause grease to build up in the tank and it is really hard to get that out once it gets a foothold so to speak.)

bjoyce · RV-Dreams Family Member

I love all these people who can leave their grey tank valve closed all the time. Even if we did not have a washer/dryer, we easily fill the grey tank in 3 to 5 days, but it takes 9 to 12 to fill our black tank. Of course with a washer/dryer, we can fill the grey tank in a day. That is how we dump, we close the grey tank, run some laundry and then black first, followed by grey.

We have not stayed long term where it goes below freezing very much, so we are not experts on cold weather. The coldest night was 13 degrees, but it was much warmer in the daylight. Mostly we deal with occasional nights in the 20s, with days above freezing. For nights in the 20s we can leave the water trickling in the sink and our water hose does not freeze.

Bill and Linda · RV-Dreams Family Member

bjoyce wrote:
I love all these people who can leave their grey tank valve closed all the time. Even if we did not have a washer/dryer, we easily fill the grey tank in 3 to 5 days, but it takes 9 to 12 to fill our black tank. Of course with a washer/dryer, we can fill the grey tank in a day. That is how we dump, we close the grey tank, run some laundry and then black first, followed by grey.

Well, for the long term good of my tanks, I consider dumping the grey tank just like taking out the trash. Takes 5 minutes and it’s a prudent thing to do, IMO. But with a washer it will fill up sooner, that’s for sure. That’s a really good clean out with the water from the washer with soap.

I guess in the case of the grey it’s a Ford / Chevy thing. Not so much as pertains to the black. :)

ticat900 · RV-Dreams Family Member

sitting hooked up LT grey tank valve always open, black tank once a week, dump and flush with tap water
why would anyone worry about flushing with the grey water when u all hooked up to city water?

BiggarView · RV-Dreams Family Member

If for no other reason it's environmentally better. Bill's reasoning about long term "crud" buildup in the grey tank thus holding and dumping grey water using his methods seems reasonable. I can think of one other reason... habit. The "dump black followed by the grey flush" is normal routine, using a different routine periodically invites mistakes.

FWIW

-- Edited by BiggarView on Saturday 23rd of January 2016 04:04:57 PM

ticat900 · RV-Dreams Family Member

to each their own one has to(or should) flush the black tank with clean water when dumping which in turn cleans out the hose,. Grey tank wont do that (flush black tank)
grey tank should never get any so called crud build up especially when using washing machine and dish washer as that's a great rinse out each time one or the other is done
using this routine in no way invites any mistakes and does the best job in my opinion

Terry and Jo · RV-Dreams Family Member

ticat900 wrote:
to each their own one has to(or should) flush the black tank with clean water when dumping which in turn cleans out the hose,. Grey tank wont do that (flush black tank)
grey tank should never get any so called crud build up especially when using washing machine and dish washer as that's a great rinse out each time one or the other is done
using this routine in no way invites any mistakes and does the best job in my opinion

First of all, not everyone has a washing machine or dish washer in their RV's, so they would not have the benefit of extra flushing of the grey tank by the use of those appliances. And yes, I think one can get a buildup of grease, or even food particles that are washed down the kitchen drain. By having water in the grey tank, the use of Dawn soap helps with breaking down the grease and the water in place may help break up small amounts of food that may be in any of the corners of the tank.

As for the use of the emptying the grey tank after the black done is emptied and flushed (we do have a black tank flush system), the water from the grey tank is just a wee bit more to run through the sewer lines to flush those lines, plus it pushes the black water further down the drain system. That may help to keep odors from working back up the lines to the tanks.

In our case, we tend to dump the grey tank after the black is dumped and flushed (just under a week's time), and then about midway through the week, it's a simple process to dump the grey and close again after dumping.

Terry

bjoyce · RV-Dreams Family Member

A handy person can install a tank flush on the grey tank. I know a couple people who routinely do that when they get an RV.