fresh water tank filling system

[nickcrowhurst]

I fill our fresh water tank about twice a week. I do this before travelling, to prevent instability from a partially filled tank. I also use tank water for showers, as we often stay at a farm where the water pressure is very low. The pump gives a much better pressure for this. When boondocking, we need to top up every few days. I find the filling procedure to be inefficient. The filler point is on the opposite side to the mains water connection. A hose has to be passed under the stabilizing jacks to avoid kinks, and the end of the hose has to be plugged and unplugged to prevent dirt from entering the end of the hose. Kneeling in the dirt, especially in the wet, is not my idea of fun. I have to find and install a fitting to allow the end of the hose to fit down the neck of the filler. To avoid this boring and messy task, I intend to buy a $15 water heater bypass kit, and install it as a "water pump bypass". When the two valves are turned to the bypass position, the city water will flow backwards into the tank, which has an air vent. When the panel indicators show "full", or I hear water overflowing out of the air vent, I can turn the bypass valves to normal flow. The bypass could include the in-line filter, but I probably won't do that. I keep that filter clean, so back-washing it won't put a load of dirt back into the tank, and I have a water filter on the outside city supply. Winterizing the bypass loop would be carried out by emptying it when the filter is emptied. Are there any aspects I haven't considered? Any reason why this wouldn't work?? Nick.

[jcanavera]

Just one point. This would be the slowness of the fill. I can dump a lot of water quickly into the tank via the external fill. Using the internal plumbing of the trailer would be extremely slow due to the diameter of the pipes.

Overall I think the concept would work.

Jack

[thenewkid64]

Nick,

This would work. In some of the units this was a factory installed option with a panel mounted switch. The only safety feature it had was it would only go to 3/4 full.

Be sure your air vent on the tank works properly. If it is plugged you could cause the tank to crack from overpressure. In fact you may want to restrict the flow so that should it overfill the air vent can handle the out flow without allowing any back pressure.

[baldeagle]

Your idea absolutely will work. Did the a similar setup on my last A/S with good results.

Given the existing fresh water filler "cap", overpressurizing the tank should not be a problem.

I rewired the non-working referigerator alarm buzzer to the 3/4 full light in the control panel. That way, when filling, i would flip the refer alarm toggle and when the 3/4 full light on the fresh water tank lit, the buzzer went off.

That little trick was done after i "forgot" i was on by-pass and the overflow out of the filler cap ended up on the galley floor.

All this in a 1983 excella.

Good Luck!


Dave S.

[Inland RV Center, In]

Extreme caution must be used when filling a water tank with the above suggested method.

If the "vent" is inadequate, water will flow into the tank faster than the vent can exhaust the air.

When that happens, the tank under the floor will vertically expand.

Severe frame and/or floor damage will occur when that happens, including buckling of crossmembers and cracking the plywood floor.

It is best, "to take the time" to slooooooowly fill the water tank.

Your check book will "love you" for it.

Andy

[nickcrowhurst]

Gentlemen, thank you for your kind advice. I shall proceed with caution, removing the filler cap each time I use the system. Nick.