dash air evap drain

Topic: dash air evap drain (Read 1093 times) previous topic - next topic

dash air evap drain

June 14, 2017, 02:09:11 pm

Hey all,
I searched the forum and found a couple threads on the dash air / heater box. I have looked to find the drain hose for my evaporator condensate tray, and have not been able to locate it / them. My AC is now working great, but the tray that forms the bottom of the housing is overflowing and putting water on the floor. My best guess is a clogged drain hose.

What I would really like to know is where on the pan the outlet that the hose attaches to is located. I am going to tear into the dash tomorrow and would like to know where my target is so I can hopefully put some air pressure on it and clear the drain tube.

This is on a 99 U270.

Thoughts, ideas, suggestions?

Thanks,
Len

Re: dash air evap drain

Reply #1 – June 14, 2017, 04:47:39 pm

Look under the front of the coach next to the generator housing, on the left side there should be a long black tube hanging down.

Re: dash air evap drain

Reply #2 – June 14, 2017, 05:28:27 pm

Bill, I have looked all around the gen housing and could not find any drain hose. What I am wondering is if it comes out of the collection pan in the middle, driver front, passenger front, passenger back, or driver back. I am hooking up an air hose tomorrow to blow out the roof AC coils, and would like to see if I can put air down through the drain on the dash AC to clear it.

Thanks for the reply.

Len

Re: dash air evap drain

Reply #3 – June 14, 2017, 05:36:39 pm

Forum search for dash air drain pulled up this post. Perhaps it applies to your '99 as well?

Dash A/C Drain Hose on 97

Re: dash air evap drain

Reply #4 – June 14, 2017, 05:48:56 pm

Thanks, Michele, I had run through that thread and a couple more, including removing the heater core, but did not ever see where it showed or told where the hose was coming out of the housing. I was just hoping someone might know off the top of their head. I have a fiber optic camera that I will use tomorrow if I don't find an answer here, but was trying to be ahead of the game come morning.

Thanks again,
Len

Re: dash air evap drain

Reply #5 – June 14, 2017, 05:52:04 pm

Len,

When you find the lower end of the condensate drain, do NOT blow in it to clear the clog. That would just put the clog back into the A/C case and allow it to "re-clog".

Sucking on it is the only reasonable solution. You can attach 8-10' of clear plastic hose to the end of the condensate drain hose and suck on that. So, you will not get any in your mouth, but you will clear the clog.

Re: dash air evap drain

Reply #6 – June 14, 2017, 06:03:41 pm

Quote from: lenspeiser – June 14, 2017, 05:48:56 pm

Thanks, Michele, I had run through that thread and a couple more, including removing the heater core, but did not ever see where it showed or told where the hose was coming out of the housing. I was just hoping someone might know off the top of their head.

Ping jor, he might know for sure - I just found this post Dash A/C Leak to Interior

Re: dash air evap drain

Reply #7 – June 14, 2017, 06:21:24 pm

Brett, thanks for the heads up. Since I have not been able to locate the drain tube, the plan is to find the drain hole and blow out, not in.
Michele-- Thanks for that link. That gives me an idea of what I will be finding when I get inside of it tomorrow. Hopefully mine will not be cracked. If it is I might just have to do a fiberglass fix.

Again, this forum is a lifesaver.

Thanks and happy trails,

Len

Re: dash air evap drain

Reply #8 – June 14, 2017, 09:00:36 pm

Here is a picture of the one on our 99' U270. This is on the passenger side of the HVAC assy.
Don

Re: dash air evap drain

Reply #9 – June 14, 2017, 09:03:20 pm

Don, That was wonderful!

It is so much easier when you have some idea of what it is you are looking for!

Thanks so much,
Len

Re: dash air evap drain

Reply #10 – June 15, 2017, 01:51:49 am

You are welcome Len. It occurs to me to mention that the drain tube exist through the floor along with the heater hoses, and the A/C lines. The drain tube is a fairly soft material and it is possible that it is pinched as it exits through the plywood rather than being plugged. It is possible that it is plugged though, considering that most of the foam material on the flapper valves HVAC Assy. is likely deteriorated to the point that it could be clogging the drain nipple which is molded into the plastic tray that underlies the heater core and A/C evaporator.
Don

Quote from: lenspeiser – June 14, 2017, 09:03:20 pm

Don, That was wonderful!

It is so much easier when you have some idea of what it is you are looking for!

Thanks so much,
Len

Re: dash air evap drain

Reply #11 – June 15, 2017, 10:44:24 am

Hey all!
Update on this thread.
First, thanks to all who took time to help out. This being our first large RV, the forum has been invaluable. Again, as someone I really admire used to say "No one in the room is smarter than everyone in the room!"

I found the outlet hose after doing contortionist yoga. It turned out to be just to the starboard (passenger) side of the gen set dog house. It was in a bundle of three or four hoses and only protruded three or four inches down from the floor boards. I "MacGivered " a brass fitting onto the end of our shop vac and put a vacuum to it three or four times.

I am going in to town to find a double barb and some clear plastic hose to extend the hose so that I can perform that cleaning function on a semi regular basis.

I am just praying that unlike jor, I do not have a split drain pan. We will keep our fingers crossed and find out the next time we move camp.

Many thanks again.

Len

Re: dash air evap drain

Reply #12 – June 15, 2017, 12:16:00 pm

Len,
If the pan was cracked it probably wouldn't be full of water. But the floor in there would be wet.

Re: dash air evap drain

Reply #13 – June 15, 2017, 12:32:38 pm

John, thanks for that reply. Trying not to tear into the heater core/evaaporator core assembly I have not been able to confirm that the pan was full or not. There was water on the floorboards under that assembly. When I dd the vacuum it did then start to dribble a little water (16 hours after shutting down that AC).

My hope is, that it was overflowing the pan, but only time will tell. Whenever possible I try to locate the simplest solution in that I am fairly simple minded!

I will keep everyone posted to help pay it forward.

Len

Re: dash air evap drain

Reply #14 – June 15, 2017, 01:06:27 pm

Len,
If it was full of water I would expect a little more than a dribble when you cleared it.
Try to follow up on Don's point that the drain hose could be squeezed where it comes down through the floor.

Re: dash air evap drain

Reply #15 – June 15, 2017, 07:18:28 pm

I had a similar problem with water getting the carpet and floor wet. The fitting on mine was broken and that caused the leak. I replaced the fitting and installed new plastic hose. Floor is now dry and water flows through the new hose. Dons picture is great and shows the area very well.

Re: dash air evap drain

Reply #16 – June 16, 2017, 02:11:35 pm

To finish up on this thread. Drove from Panther Creek TN to Asheville NC with the A/C working overtime. Not a drop on the floor.

I got lucky and the drain vacuum did the trick.

Thanks again, all!

Len

Re: dash air evap drain

Reply #17 – June 16, 2017, 02:40:16 pm

Len,

A common problem and the standard "first step" in fixing it.

Re: dash air evap drain

Reply #18 – June 20, 2017, 04:26:20 pm

I extended the a/c drain hose and took the opportunity to take a couple of photos for future reference. If you are lying under the rig just on the passenger side of the generator box and look up, you'll see photo #1. If you pull the hoses apart (photo #2), you should see the condensate hose. I just slid a piece of 5/8" heater hose over the drain hose (perfect fit) and attached it to the generator box.
jor

Re: dash air evap drain

Reply #19 – August 30, 2018, 01:43:11 pm

I'm reviving an old topic in order to add a relevant update. The original thread deals with clearing a clog in the dash AC condensate drain. While replacing my heater core recently, I discovered that a clog may not be the only reason your AC doesn't drain. On mine, whoever ran the hose routed it up and over the AC duct. The hose is at least several inches higher than the drain port. This is a gravity drain system so there's no way this could have ever worked. As far as I can tell, this is the original installation. I don't know how but in 20+ years of being this way, there's no evidence that the pan ever overflowed. I feel very lucky to not have major floor damage under the dash. It's now being routed correctly.

Re: dash air evap drain

Reply #20 – September 04, 2018, 10:56:47 am

My AC evaporator drain line is now routed so that it actually drains for the 1st time. While removing the drain line for the heater core replacement I accidentally broke the connector inside the hose. The connector also broke loose at the pan. That was repaired with some 5200, then a piece of 3/8" tubing was inserted into the pan and the hose. A tight fit at both ends creates a water tight seal. The hose was then routed and secured lower than the pan drain.

While working on this, I found that the damper that controls fresh air vs recirculated air on the supply side was not working. The axle rod is normally held in the plastic plenum housing, which had broken. The axle rod is now secured in it's proper position with a new bracket. The gap in the plenum was sealed with foil tape after these pictures were taken.

The air handler box is now working as it should, although temps at the dash air vents are not as low as they should be. I wrapped the tail pipe in front of the condenser to reduce any issues with radiant heat. Still only getting about a 20deg drop from ambient so it will probably be going back to the local shop that has replaced the compressor, drier & expansion valve for adjustment now that the other issues are resolved.

Re: dash air evap drain

Reply #21 – September 04, 2018, 06:48:46 pm

To get an ongoing evaporator coil temperature, we put a small wired sensor thermometer on dash, with sensor wire fed down to coil. Even when we don't feel as cold as we would like, when the thermometer says 38-48 degrees, we know things are working ok. BTW, we have a similar setup for ceiling A/C.

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