Water dripping from bottom of front cap (Reflection 337)

[Second Chance]

I let my wife and the tug of grandkids at Christmas keep us much farther north than I would like to be this time of year. We are staying at Aberdeen Proving Grounds northeast of Baltimore, MD, until 4 January 2017. Anyway, the temp got down to about 28 night before last, but there's no precipitation of any kind since we arrived last Thursday. Yesterday morning I stepped outside to find a couple of small puddles on the concrete just on either side of a vertical line down from the kingpin and a slow drip of water coming off the inside end of the plastic trim where the front cap joins the underside of the front overhang. It didn't seem to be enough water to be a pressurized leak from the water lines for the washer (the only plumbing up in that area). But, Ssnce we don't have a W/D, I depressurized the water system, cut the Pex lines for the washer down in the basement, and inserted a couple of good quality ball valves before turning the water back on (with the ball valves closed, of course). I tested the washer connections and there is no water or pressure making it past the ball valves in the basement, now. Yesterday afternoon the drip from under the cap seemed to stop and the sun dried up the little puddles on the concrete.

Temps got down to about 24 last night. We kept the main thermostat set on 62 and it cycled regularly through the night. I went outside this morning to check things out and found the puddles again with water dripping from the same places - with a couple of small icicles forming.

Here's my question: could there be enough humidity in the air in the front bedroom/closet from two of us sleeping in there at night for air to find its way to a front frame member with the moisture condensing to drip wherever it can find a way out? I have two concerns: 1) Since the top side of that thin panel on the bottom of the overhang seems to be very thin Lauan plywood, I'm worried about both wood rot and expansion damage should this water freeze up in there, and; 2) fear that I'm missing something concerning the source of the dripping water. Any thoughts, suggestions or similar experiences from members? Input from Grand Design?

Thanks,

Rob

[TucsonJim]

The only source of water other than condensation in that area of the 337 is the washing machine hook up. But it runs up above the basement, so that shouldn't be an issue. Here's what I'd do to make sure you don't have a leak.

1. Make sure you have water in the fresh water holding tank.
2. Disconnect from an outside water source.
3. Set up your valves for water from the tank.
4. Turn on the pump.
5. Run all the faucets and flush the toilet to make sure there is no air in the system.
6. Leave the pump on and if you hear it cycling from time to time, it's losing pressure and you may have a leak that needs to be investigated.

If there is no leak, it's most likely warm moist air escaping from the front of the coach and making contact with cold outside air. It condenses and creates the moisture you're observing. On the 337, you have all those storage cubby holes in the front of the closet. Warm moist air could easily be migrating out of one of those into the area you're seeing. You might try caulking all around those shelves and any seams to try and seal the front of the unit up.

Jim

[Second Chance]

Thanks, Jim - I knew about the pump cycling thing but hadn't thought about using it this week for diagnostic purposes. We're over at the kids' the next few nights, but I turned off the water for the RV before we left and depressurized the system. When we get back, I'll do both the things you suggest... water pump test and pull everything out of the front closet (needs a good cleaning, anyway) and check for possible air leaks, etc.

Rob

[Big Mike]

It is frost/dew from the roof running down the front trim and dripping off.

Big Mike

[RamGunner]

It is frost/dew from the roof running down the front trim and dripping off.

Big Mike

That's my thought as well. Happens to us all the time.

[Second Chance]

I'm hearing you, "Condensation Guys," and will investigate that further, too, when we get back to the rig this week.

Rob

[Timyarmer]

I know the thread is a few years old but we are having issues with severe amounts of water coming from our nose cap with only 25 percent humidity on the inside of the trailer...I pulled the shoe cubby fro the front of our coach and found no insulation or vapor barrier on about 1/3rd of the nose cap and could feel air movement in that cavity. Did you ever find the cause of your condensation?