What is this other drain pipe under the rear of my trailer?

MikePro

Member
I recently purchased a 2013 Heartland Prowler 32P BHS on a seasonal site. According to specs I have read online the trailer has 1 fresh water tank, 1 grey water tank and 1 blackwater tank. The drain for the grey tank and the drain for the black tank flow into a single connection under the trailer between the slides at the rear of the tires. There is an individual tank valve drain handle on each side of this common sewer connection and it flows into a septic tank. Now, under the rear of the trailer there is a another drain pipe with a valve at the end of it. This pipe comes out of the lining under the trailer and drops at a slight angle and has a cap on the end. It is not connected to the septic tank. I cannot find anything that tells me what this pipe is for. What is it? And, should it be linked to the other drain/s and run into the septic? It's also getting close to winterizing time and I also need to know if I should open this drain to ensure there is nothing in the pipe. The pipe is about 3 to 4 feet long.
 

Oregon_Camper

Well-known member
That would be the fresh water drain. You will want to let that drain out to winterize. If you see 2 lines together, normally red/blue lines, those were used in some RV's to drain the water lines, prior to winterizing.
 

MikePro

Member
Thanks for the replies. The trailer has a red, and a blue, low point drain just under the right rear corner of the trailer below the outdoor bar/kitchen. In this same area it has some sort of air hose connection where I think I could use an air compressor. The black pipe that I cannot figure out is at least a 3 inch diameter pipe and the end on it is similar to the one where the present black water hose is connect just behind the wheels.
 

MikePro

Member
The air hose connection is more likely a propane connection for a grill.
I believe you are correct as there is a fold down located on the rear bumper in that corner for an outside grill. I noticed that the line from that fitting ran along the trailer frame towards the front where the propane tanks are located. Thank you. Slowly learning about all the fittings and drains. It's strange that the trailer manual the previous owners left me doesn't show this.
 

MikePro

Member
Still haven't been able to figure out what this second pipe is under my trailer so I will post some pictures. The drain to the left of my white tank, (drain1.jpg), that is attached to the tank has the grey water drain valve and the black water drain valve. To the right of my white tank towards the rear of the trailer is this second pipe, (2nd pipe.jpg & drain pipe 2.jpg), that I am concerned about. When I go out to winterize the trailer I am going to open this pipe to see what comes out. I am also wondering if this pipe should have been plumbed into the white tank. Thanks folks.
 

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Oregon_Camper

Well-known member
Either ask prior owner or drop the underbelly to determine where that is attached. It doesn't look like a factory install but rather something a prior owner did to it.

Is this pipe pointing out the back or the same side as the other pipe (where we see the sewer hose attached) Hard to tell from the images you posted. Perhaps either the original black or grey tank drain pipe failed and prior owner added this one?
 
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taskswap

Active Member
Definitely looks DIY, with the dump valve sideways instead of facing out. I'm in the "drop the underbelly" camp as well. If that's daunting, get a cheap endoscope on Amazon and poke around in there with it. I'd also be looking for mystery switches. One thing I always wanted to do in my last camper was add a grey tank to an unused underbelly space, with a transfer pump. Maybe they did something "clever"...
 

MikePro

Member
Does your rig have 2 bathrooms, or perhaps an outside kitchen?
I have an outdoor bar with a sink, rear right side, and a single bathroom just ahead of that on the right side.
 

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MikePro

Member
Either ask prior owner or drop the underbelly to determine where that is attached. It doesn't look like a factory install but rather something a prior owner did to it.

Is this pipe pointing out the back or the same side as the other pipe (where we see the sewer hose attached) Hard to tell from the images you posted. Perhaps either the original black or grey tank drain pipe failed and prior owner added this one?
It is pointing out the same side as the other pipe.
 

MikePro

Member
Definitely looks DIY, with the dump valve sideways instead of facing out. I'm in the "drop the underbelly" camp as well. If that's daunting, get a cheap endoscope on Amazon and poke around in there with it. I'd also be looking for mystery switches. One thing I always wanted to do in my last camper was add a grey tank to an unused underbelly space, with a transfer pump. Maybe they did something "clever"...
Thanks, I just may have to look inside the underbelly.
 

danemayer

Moderator
Staff member
I have an outdoor bar with a sink, rear right side, and a single bathroom just ahead of that on the right side.
I would think that both of those drain into a separate tank nearby, that in turn drains through the mystery sewer outlet. It's not unusual in layouts like these to have two separate sewer outlets. Required vertical drop over distance for the sewer pipe can make it impractical to connect the rear tank to the front sewer outlet.
 

MikePro

Member
Okay folks I figured it out. I dropped the underbelly covering and that rear pipe goes into my black water tank. Thus there must be two black water drains on my trailer. Will pick up another hose and connector so I can make sure this pipe is drained and has nothing remaining in it for the winter.
 
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