Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Don & Tys on July 01, 2013, 04:30:21 pm

Title: Fresh Water Overflow Vent Project
Post by: Don & Tys on July 01, 2013, 04:30:21 pm
Since I have had everything out of the freshwater compartment, putting it back together from a blank slate creates some opportunities to make changes that wouldn't otherwise be feasible. I have routed the Vent/Overflow up through the floor and looped it back down through the original bulkhead penetration. I ran a 1" PVC pipe down the backside of the bulkhead to be able to direct the overflow away the bulkhead joint. Time will tell if this will be a successful strategy or not, but I am betting that it will function as I designed it to. I put in a tee in the loop with a riser and an inline vent inside of the laundry hook up cavity. I could of course short circuit the loop and run the overflow right through the bulkhead and still have the benefit of the pipe to direct the water away from the bulkhead joint, but I would first have to take the water heater out to accomplish this. So those are the stakes of my bet... ::)
Don
Edit: I should mention that since our washer hook ups were leaking and I needed to replace the valves. I used the inch and a half hole that the washer hook up Pex lines ran through for my 1-1/4" PVC overflow/vent loop (happened to be in the right place) and that I drilled to new holes to reroute the washer hook ups to their respective sides of the manibloc for more direct routes. I also mounted the valves 180 degrees from where they were originally to give more space to open and close the valves.
Title: Re: Fresh Water Overflow Vent Project
Post by: Rick on July 02, 2013, 04:17:54 pm
Don,
 If I had mine that far apart, I would look into running those vent lines to the roof. I hate those springy poppet type vents.
Bye
Title: Re: Fresh Water Overflow Vent Project
Post by: Don & Tys on July 02, 2013, 05:55:09 pm
Thanks for the thought Rick! I have actually considered that and may still do that eventually since I could do it mostly from inside the closet without taking anything else apart. My hesitation at the moment is that I have about 408W of Unisolar flexible panels going up (with the possibility of another 408W in the future), and due to the size, they are going to be very tight placements. So before I will penetrate the roof, I will have done the solar panel installation first.
Don
If I had mine that far apart, I would look into running those vent lines to the roof. I hate those springy poppet type vents.
Title: Re: Fresh Water Overflow Vent Project
Post by: Chuck Pearson on July 02, 2013, 11:44:48 pm
Before you run another vent line or install an automatic vent,you might consider this.  The only reason for vents for fixtures is to prevent siphoning the P trap dry which will allow sewer gas inside.  They also are necessary for flush toilets in houses but that's another issue.  The only way I see to fill the drain lines to a point that would allow sufficient negative pressure to siphon a trap would be if you had a bath tub, and, maybe, if you filled a sink completely full and then dumped it. Of course you could seal it again by running a few ounces of water to refill trap.

 Since I do neither in the RV, the auto vents will be replaced with solid caps.  Of course the black and grey tanks need to be vented but that's taken care of.  I'm sick of these sewer gas emitters and am convinced they are unnecessary.  We'll see....
Title: Re: Fresh Water Overflow Vent Project
Post by: gam on July 03, 2013, 12:20:28 am
The air admittance valves are used to prevent sucking the seal water out of any p trap on the leg of the system that doesn't have a stack. The full kitchen sink my suck the water out of the washing machine or the washing machine my suck it out of the shower drain. Without them you may be chasing bad smells from drain to drain. I think I would rather have the air admittance valve in a good location then another roof penetration.They also allow the water to flow faster in the drain lines and help to prevent a gurgling sound in the system.Gam
Title: Re: Fresh Water Overflow Vent Project
Post by: Dave Katsuki on July 03, 2013, 01:25:28 am
Driving the coach at highway speeds (and often with a headwind or cross-wind) may also cause enough vacuum in the roof vent to empty the p-trap without the auto vents - another reason why they may be there.
Title: Re: Fresh Water Overflow Vent Project
Post by: gam on July 03, 2013, 06:51:58 am
I never though of what purpose they may have on the road but I think your correct. That may be why they go bad as often as they do in a coach and not when installed in a home.Gam
Title: Re: Fresh Water Overflow Vent Project
Post by: Chuck Pearson on July 03, 2013, 09:24:25 am
Easy enough to find out what the effect of removing them is, I'm going to give it a try.  The vacuum effect from driving may well be the deal breaker though driving is usually when the smell occurs with the vents installed.  I know when winds climb much over 75 mph at our place the traps in the house sometimes are sucked dry...you notice it instantly. 
Title: Re: Fresh Water Overflow Vent Project
Post by: Dave Katsuki on July 05, 2013, 12:55:36 am
You can try disabling them with out replacing by just wrapping them with duct tape.
Title: Re: Fresh Water Overflow Vent Project
Post by: Chuck Pearson on July 05, 2013, 08:38:34 am
You can try disabling them with out replacing by just wrapping them with duct tape.

Excellent idea, will do.  Probably won't remove the washer to get to the one inside the enclosure, too lazy. 
Title: Re: Fresh Water Overflow Vent Project
Post by: lgshoup on July 05, 2013, 12:16:03 pm
Don, Keep me posted as to when you're going to be through with your coach. Since you seem to enjoy working on them I'll just drop our off and take yours until such time as you get the to-do list done on ours.
Title: Re: Fresh Water Overflow Vent Project
Post by: Don & Tys on July 05, 2013, 12:21:14 pm
I know these vents are usually used to vent waste pipes... Our coach has 4 of these. Two in the closet where the washer hooks up (I added the second when I put the washer in... or maybe I just moved it, don't remember now...), and one each in the kitchen sink cabinet and bathroom vanity. I learned the smelly lesson when one of these vents went bad... the vent I added for the overflow loop is solely to allow water into the fresh water tank when the overflow pipe is full of water. I am not totally sure it is necessary, but I thought I might want to cap the overflow pipe when traveling with a full tank and then there would need to be a source to let air into the tank. At any rate, the new vent shouldn't result in in any smelly episodes if it were to go bad. As a result of testing my system, we won't be traveling with an over full FW tank. I will either stop the fill before the vent hose is completely  full or drain enough to uncover the opening before hitting the road. The reason for that is when filled to the point where the overflow/vent hose is full of water, I could see bulging on the top of the tank from trapped air (because of the fact that the overflow/vent fitting on the fresh tank isn't at the highest point). I don't think the pressure could be that much, but I don't want to put any extra strain on the tank.
Don
Title: Re: Fresh Water Overflow Vent Project
Post by: Don & Tys on July 05, 2013, 03:33:25 pm
Larry , It is all a means to an end, but I might be able to start on your list by 2063 or so... ;D
Don, Keep me posted as to when you're going to be through with your coach. Since you seem to enjoy working on them I'll just drop our off and take yours until such time as you get the to-do list done on ours.
Title: Re: Fresh Water Overflow Vent Project
Post by: lgshoup on July 18, 2013, 05:30:04 pm
Don, The beauty of a Foretravel is that it will probably last until 2063!