Air conditioner drain lines plugged?

[Jim]

I was up early and heard a small drip, drip, drip. Found it coming out of the small, disk light above the passenger seat. There's an air conditioner on the roof, just above this light, and I think the drain lines coming from the pan that the conditioner sits may be clogged, and the water is coming over the sides and then down into the coach.

So when the sun came up, I looked at the lines. There is condensation coming out both of them, just not as much as I would expect.

Drivers side has what appears to be unrestricted flow.
Passenger side, not so much.

I took a shop vac and tried to blow the lines out. But the lines just don't seem to be clear at least it seems that way because the air isn't flowing like I would have expected.

So the question is, should I put some serious air pressure through the lines? Or do they terminate somewhere different that where I think they do, and the added air pressure might do more harm than good?

2016 London Aire

Picture 1 Drain line Drivers side
Picture 2 Drain line Passenger side

 

[CaptainGizmo]

Jim,

I can tell you our Newell’s system and diagnosis; hoping it gives you direction.

Units like the Mach8 have a pump and float in the pan that can malfunction. As a routine check, we have to pull the access panel off from INSIDE the coach, where you can see if it’s working.

We have a sight tube inline on the drain line and we use a water bottle with a sharply bent straw (like football players use with their helmet on) to squirt water into the drain tray. When the AC is running that float and pump should work intermittently to purge the water out. If not, then we can take that sight glass off and blow the line with compressed air.

 

[Jim]

I believe you nailed it @CaptainGizmo ! And it appears the pump has decided it was time to leave us.

Thank you for the reply.

 

[Jim]

Quite sure the pump is the problem. The drivers side it working well, lots of water coming out the drain tube. The passenger side is not working at all.

It's way to hot to climb up on top of the rig right now, so I've turned off the front air conditioner and let the other two handle the cooling. Might have to turn the front back on intermittently as it's hitting high 90's here today. But we'll see how it goes.

Thanks again, @CaptainGizmo

 

[CaptainGizmo]

Quite sure the pump is the problem. The drivers side it working well, lots of water coming out the drain tube. The passenger side is not working at all.

It's way to hot to climb up on top of the rig right now, so I've turned off the front air conditioner and let the other two handle the cooling. Might have to turn the front back on intermittently as it's hitting high 90's here today. But we'll see how it goes.

Thanks again, @CaptainGizmo

Jim,

Just so ya know…I was surprised to find out the drain pan AND pump/float can be accessed from UNDER the AC unit INSIDE the coach! Hope that keeps you out of the heat.

 

[redbaron]

Jim: Newmar doesn’t use mach8 or a pump. The drains you have are roof drains.

I would start with less than 30psi of opreasure to work loose, ***BUT*** none of this explains water in the ceiling.

That’s a separate issue.

My guess is you have a failure of a seam caulk or dicor around a roof intrusion. You need to inspect that.

The alternate problem is a failure of the pex line which is a joint in the roof, but that does not go over the area you indicated.

Check the roof first.

 

[CaptainGizmo]

Jim: Newmar doesn’t use mach8 or a pump. The drains you have are roof drains.

I would start with less than 30psi of opreasure to work loose, ***BUT*** none of this explains water in the ceiling.

That’s a separate issue.

My guess is you have a failure of a seam caulk or dicor around a roof intrusion. You need to inspect that.

The alternate problem is a failure of the pex line which is a joint in the roof, but that does not go over the area you indicated.

Check the roof first.

Thanks for the clarification, Ronnie...I couldn't remember my Dutch Star's config, so I took a stab at it.

I've asked if blowing from the "bottom end" was a good idea but...for the reasons above...not necessarily good. They've said, "Easy...but may end up making your day worse if there's a blockage and you blow a line apart or blow water where it shouldn't be."

So, I did it anyways...LOL...I love to live on the edge.

 

[redbaron]

I do blow on mine to clear the lines. Never more than 30psi. Usually just a small hand pump sprayer that’s empty. That’s usually enough air to loosen and allow it to drain.

 

[lostinfla]

I just use a water hose to clear my roof drains. Squirt a little water up the line and the vacuum as it comes out usually clears the line. I also extended the drains to come out the bottom of the coach for easier access and visible confirmation that they are not clogged. Pics of rear, but I also did the front.

 

[Neemer]

@lostinfla I like that. Good idea. I’m stealing it.

 

[Jim]

Thanks to everyone for the suggestions and ideas. Now here is a part that is quite confusing. We drove in this mess for a couple of hours, not one drop of water came inside the coach. And this was a LOT of rain, believe me! Any ideas why the water from the HVAC makes it way in, but this monsoon didn't weald a drop?

 

[MemoriesByTheMile]

Typically the water in the A/C pan is forming inside the coach, when the moisture is condensing on the cold evaporator coil. It drips off that evaporative coil into the water pan and then either gravity or a pump (if so optioned) will remove the water down the tubes. Same thing happens in home A/C units.

This is why A/C units dry out a house or RV, they are removing the moisture from the air and then draining it away as water.

 

[Neemer]

Thanks to everyone for the suggestions and ideas. Now here is a part that is quite confusing. We drove in this mess for a couple of hours, not one drop of water came inside the coach. And this was a LOT of rain, believe me! Any ideas why the water from the HVAC makes it way in, but this monsoon didn't weald a drop?


View attachment 28551

Driving in rain like that absolutely exhausts me.

Jim, I don’t have the answer to your question. I could only speculate which would not be helpful. I can tell you what I would do though. I’d pull the shroud off that A/C unit and have a look inside. It might reveal something.

 

[CaptainGizmo]

Thanks to everyone for the suggestions and ideas. Now here is a part that is quite confusing. We drove in this mess for a couple of hours, not one drop of water came inside the coach. And this was a LOT of rain, believe me! Any ideas why the water from the HVAC makes it way in, but this monsoon didn't weald a drop?


View attachment 28551

Well, this still goes back to starting at the Drain pan. I would check to see if it has water sitting in it.
You had mentioned the other side IS draining (pumping) fine. So…you’re saying you DO have a pump in your units. So, if so, fill that pan up and see if it pumps it clear and then check for that leak.

I would expect Newmar to run a solid piece of drain line just for the simple reason of not having a fitting that leaks midway.

If you can’t figure out where the leak is, then it’s huntin time with cameras shoved into those tights spaces to find the source.

I hope, for your sake, the leak is just traveling and can be found easily. I’ve known of roof leaks migrating literally across or down a coach, far from the source.

Oh. Incidentally, whenever I’m worried about a leak being AC or Roof, I intentionally throw my coach way off level. This is because, on humid days, my AC units produce a lot of condensation on the roof outside of the drain pans which will pool up and drip down the windshield. Just another way of diagnosing.

 

[lostinfla]

I'm a little confused. As far as I know, on our coach the evap condensation just runs out of the base of the unit on to the roof and down the roof drains. No pump or drain lines.

 

[redbaron]

I'm a little confused. As far as I know, on our coach the evap condensation just runs out of the base of the unit on to the roof and down the roof drains. No pump or drain lines.

You’re right, I explained that in #6 above.

My guess is the intrusion is not related directly to the air conditioner, but more likely the radio antenna or other rooftop items above driver.

 

[GUS2000]

we have a similar issue in our DS4369 and in the bedroom only... it go to the point where water was even dripping from one of the lights in the ceiling.. no rain just condensation from the ac.. last year when we were at Newmar they pulled the rear most AC and cleaned it out and resealed everything... so far we only get a small drip of condensation forming on the grill depending on how humid it is... whats weird is the front ac runs 2x as much as this ac and never had any issue like this.. so thinking if it does it again, there is something with this specific AC thats not draining correctly as the other two never show this issue..

 

[lostinfla]

Just so happens, I was up on the roof early this am to clean the coils and while in there I had a thought. If the pan below the evaporator is cracked, it will leak water into the plenum and inside the coach instead of following the drain route. Not sure if this is the issue, but it is a possibility. (This pic is before I cleaned it)

 

[CaptainGizmo]

Sorry for introducing any confusion or incorrect guidance regarding having a pump.

It’s clear from @redbaron and @lostinfla that they do not…I apologize for the wrong “rabbit hole”!

But, if ya didn’t have a leak in that pouring rain, and ONLY when a certain AC is on, then yeah…sure sounds like a clogged and/or leaking drain line, pan, or pan to roof seal.

I would be inclined to try to isolate by working from the outside, inward; pouring water around the housing, then around the pan, then in the pan.

Help ya get it!

 

[Jim]

Sorry for introducing any confusion or incorrect guidance regarding having a pump.

It’s clear from @redbaron and @lostinfla that they do not…I apologize for the wrong “rabbit hole”!

But, if ya didn’t have a leak in that pouring rain, and ONLY when a certain AC is on, then yeah…sure sounds like a clogged and/or leaking drain line, pan, or pan to roof seal.

I would be inclined to try to isolate by working from the outside, inward; pouring water around the housing, then around the pan, then in the pan.

Help ya get it!

LOL, yeah, there’s always going to be some confusion when dealing with this stuff.

I talked to an RV tech at the park where I stay, and he agreed that newer rigs probably do have a pump. That said, neither of us could figure out why anyone would want to add another layer of complexity to something that’s worked just fine for years without one.

I don’t think it’s a broken pan like @lostinfla suggested, though I suppose it’s possible. But we ran the A/C for the full 10-hour trip, and not a single drop of condensation showed up. If the pan were broken, or leaking, I think this would have been a good time for it to leak. So yeah, it looks like I’ll need to put some time into this mystery, but these days, time’s harder to find than a good politician.

Anyway, I’ll get it sorted. Just going to take a little effort.