Draining water tank on 99 Tradewinds

[tufftj]

Just some info for anyone that has a similar model. I blew my fresh water tank due to clogged overflow, so I had to find where the tanks were and the associated plumbing.
I found two 45 gal tanks located forward over the fuel tank in their own heated compartment.
In the most forward compartment behind the front tire on passenger side was a small panel in the upper left corner velcro'd on to the wall when removed revealed the tank drain valve with attached hose to the ground. The overflow hose (with a piece of wood jammed into the bottom of the hose and wrapped with electrical tape) was beside the drain hose.
Being new to RVing and this MH, I did not realize that the tanks didn't have to be filled to use City Water. I just assumed that the tanks got filled and the pump was used to get water into the MH (I did read ALL the books and literature that came with the MH) .

Anyways that's why I'm posting this info.

[Theberrys]

Well that was the wrong fix to a common problem that created a worse problem. He probably stuffed the overflow hose to prevent the siphoning that happens when you follow the instructions for filling the fresh water tank. If you fill it to the top it overflows like the manual says but will continue to siphon the tank till you have very little water left. Now the pressure has built up to the point of rupturing the tank and giving you a much worse situation. I'm not sure what method to use to repair the tank, or even if you can repair plastic when split.
I have replaced fittings on the input side because the check valve failed on the city water input fitting. I bought one at my local RV shop and needed to add a nipple to get the gender correct. I really don't think the Teflon lining is required inside the fittings if you use PVC, especially on the overflow side since water, in theory doesn't get there very often and when it does it's going out not in.
When I fill my Fresh Water Tank I stop around 2/3 reading on the monitor panel to avoid the siphoning problem, but I know of at least one other coach where a valve has been installed to allow filling without damaging the tank. Then after its full they close the valve to prevent the siphoning. But that adds a whole new process to filling the tank and since we don't dry camp very often filling just past the 2/3 level covers it for us.
Dick

Ps: I got your PM and just chose to answer here…. I didn’t ignore it.

[Geezer38]

[QUOTE=Theberrys;1332312]Well that was the wrong fix to a common problem that created a worse problem. He probably stuffed the overflow hose to prevent the siphoning that happens when you follow the instructions for filling the fresh water tank. If you fill it to the top it overflows like the manual says but will continue to siphon the tank till you have very little water left.

As a new owner of a 1999 Tradewinds 7370 which I won't take possession of until next April I find this thread very interesting. I don't understand the "siphoning" comments if the tank vent is located at the top of the water tank where it should be. As soon as the water level in the tank drops below the tank vent outlet the siphon action will stop. I can see that depending on the vent location on the tank, if the vent hose is not either looped high enough to stay above above changes in the tank water level caused by acceleration/deceleration or coach tilt or led to a high enough outlet on the RV exterior it is possible for water to be forced out the vent, simply draining the tank or starting a siphon action until the water level is again below the vent outlet. Marine stores have a simple anti-siphon valve which would appear to be an easy fix for this problem if the vent hose can be run appropriately.
Terry
Shelburne, VT

[Theberrys]

[QUOTE=Geezer38;1371743]

Originally Posted by Theberrys

Well that was the wrong fix to a common problem that created a worse problem. He probably stuffed the overflow hose to prevent the siphoning that happens when you follow the instructions for filling the fresh water tank. If you fill it to the top it overflows like the manual says but will continue to siphon the tank till you have very little water left.

As a new owner of a 1999 Tradewinds 7370 which I won't take possession of until next April I find this thread very interesting. I don't understand the "siphoning" comments if the tank vent is located at the top of the water tank where it should be. As soon as the water level in the tank drops below the tank vent outlet the siphon action will stop. I can see that depending on the vent location on the tank, if the vent hose is not either looped high enough to stay above above changes in the tank water level caused by acceleration/deceleration or coach tilt or led to a high enough outlet on the RV exterior it is possible for water to be forced out the vent, simply draining the tank or starting a siphon action until the water level is again below the vent outlet. Marine stores have a simple anti-siphon valve which would appear to be an easy fix for this problem if the vent hose can be run appropriately.
Terry
Shelburne, VT

Everything you say rings true to me, and yet when I fill to overflow it ends up at about 1/3 of a tank. Since we don't boondock it hasn't been a issue worth dealing with and 2/3 tank is plenty for us on the road.

DIck

[Geezer38]

Guess I'll find out myself in April. Thanks,Dick, for all your info on the Tradewinds. I'm avidly digesting all of it!!
Terry

[wb7auk]

As to tank repair with crack drill a small hole at the ends of the cracks, then fiber
glass the crack area using the cloth and glass.

I think Dick is talking about the cure taken on my MH where the tank vent line
was ran over to the water compartment and a 2 way valve installed that allows
it to vent for filling and use and in the other position keeps the system closed.

[Theberrys]

Originally Posted by wb7auk

As to tank repair with crack drill a small hole at the ends of the cracks, then fiber
glass the crack area using the cloth and glass.

I think Dick is talking about the cure taken on my MH where the tank vent line
was ran over to the water compartment and a 2 way valve installed that allows
it to vent for filling and use and in the other position keeps the system closed.

That's it Art. That manual valve is the surest way to handle the problem, it's just another thing to remember when filling the tank or the fresh water tank will get pressureized and have the same results as the OP.

Dick

[wb7auk]

Originally Posted by Theberrys

That's it Art. That manual valve is the surest way to handle the problem, it's just another thing to remember when filling the tank or the fresh water tank will get pressureized and have the same results as the OP.

Dick

If one does not watch the vents when filling the same problem will occure
when the tank gets full as the vent hose will not discharge the water as
fast as it is going in.(been there and done that)