Houghton Retrofit Process & Questions

[Geronimo John]

With the number of "bandito posts" on other's A/C topics (Such as the Truma threads), I figured that a separate post for those retrofitting their Domestic's to the Houghton A/C units would be in order.  That way the Truma Team won't have to listen to all our interruptions on their threads.  🙂

It would be wonderful if our moderator(s) could relocated the many bandito posts (such as mine and others) to this thread. 

And God bless our moderators. 

Mahalo,

GJ

[Geronimo John]

 

On 12/19/2022 at 4:41 PM, katanapilot said:  Or $1500 for the RecPro/Houghton 13.5k heat pump and maybe 4 hours labor? Cheaper yet and you can use the heat function versus propane if you have 120 volt power. 

The Black Friday additional 15% discount seems to have passed.  However the RecPro/Houghton 13.5 K, non ducted, WITHOUT the heat pump is still being sold at a great price.  Remember to ask for the 5% new customer discount.  Here are their current "No Heat" and their "With Heat Pump" versions prices:

NOTES: Be aware that:

• The one on the left is significantly higher (13 11/16") than the low profile one on the right (9" High).
• The one on the left is 73 pounds, and the one on the right is 99 pounds.

GJ

  

Edited December 25, 2022 by Geronimo John
Added Caution about heights and weights of units. Not apples to oranges.

[Geronimo John]

Do any of our Houghton AC owners have info about the Houghton condensate drain process out of the unit and onto the Ollie roof?  

I am contemplating retrofit the Houghton with the Dometic add-on condensate drain hardware.  See picture below.

Thanks

GJ

NOTE:  Thanks Steve CR for the above picture!  🙂

Edited December 31, 2022 by Geronimo John
Added note crediting Steve CR for the great picture.

[Geronimo John]

I spoke with RecPro today about their 13.5K BTUH low profile units.  Sadly, they have no engineering support what so ever.  Could not answer any of my engineering questions:

• Did not know about our have any knowledge of use of Dometic Auxiliary Drain Kits as OTT uses.
• Did not know what kind of compressor they use. (Scroll, inverter, reciprocating or if it has a variable speed or step speed function. etc.)
• Did not know how the fans work (Multi-speed control, winding based speed-control or if they are just single speed.)

They do have a wiring diagram though and it is provided with the unit.  I asked if it was online and..... she did not know.  

So I changed my order and went with the 13.5K BTU unit.

I think that if I use the OTT method of raising the A/C unit, that the Dometic Auxiliary Drain Kit may work on the Houghton units.  Their bolt pattern is at 13.5.  If our roof penetration is an actual 14" X 14", then I could run the drains together on the air return open duct to the existing 1/2" OTT through the wall drain line.  This is still perking in my noodle.

HOWEVER, one thing I did learn was that according to the RecPro Customer Service Contact (Sherrie), there have been two "Sets" of Houghton's.  The first did NOT run the fan continuously.  The Second Set does.  She stated that the change was made by the Aussies and she did not know why.  I stated that for at least 1/3 of US trailers it was a bad decision and certainly wasteful of energy.

 

 

[SeaDawg]

On 12/25/2022 at 6:40 PM, Geronimo John said:

Do any of our Houghton AC owners have info about the Houghton condensate drain process out of the unit and onto the Ollie roof?  

I am contemplating retrofit the Houghton with the Dometic add-on condensate drain hardware.  See picture below.

Thanks

GJ

 

Since we rarely use the ac,  we didn't worry about the drain .

[SeaDawg]

2 hours ago, Geronimo John said:

HOWEVER, one thing I did learn was that according to the RecPro Customer Service Contact (Sherrie), there have been two "Sets" of Houghton's.  The first did NOT run the fan continuously.  The Second Set does.  She stated that the change was made by the Aussies and she did not know why.  I stated that for at least 1/3 of US trailers it was a bad decision and certainly wasteful of energ

I wonder if there's  a software switch to change it back?

[Geronimo John]

16 hours ago, SeaDawg said:

I wonder if there's  a software switch to change it back?

I asked if I could switch it back to Type 1, and sadly, they had no idea. 

[Geronimo John]

POSSIBLE “OVER-THE SIDE” CONDENSATE DRAIN MOD

One of the two disadvantages of the current version of the Houghton 13.5K BTUH unit install is the “Over-the-Side” condensate concern.  I am pondering solutions to this issue and am asking for your help in vetting this concept.  The below is an obvious plagiarism of OTT’s solution with Domestic’s drain kit.  

For the OE2 Dometic's, the evaporator condensate drains into one of two plastic “Drain Pans”.  It then gravity drains from the rooftop mounted drain pans to the T fitting.  Then gravity feeds the condensate down inside of our hull.  I don’t know for sure, but this likely is the Dometic Kit they use.  Please advise.)

The Dometic Auxiliary Drain Pan Kit’s elevation spacer gaskets (3 each shown above) raise the A/C unit up enough to run drain tubing back into the roof penetration area. The weight of the unit is supported by the roof penetration kit gasket, and at the aft end of the unit by the two support gaskets shown above. 

Dometic Install:  Per the Dometic photo below, the are no interferences with the routing of the auxiliary drain pan kit.

Houghton Install:  However, since the Houghton has an internal supply air round transfer duct (shown below as a white circle), this obstruction may require rerouting of the drain lines.  Here is what the Houghton underside looks like:

• There appears to be space outside of the air transfer duct and the sides of the roof penetration and elevation spacer gasket to run the drain tubing.  

• Another possible route is inside the elevation spacer gasket and the 14” X 14” hull roof penetration areas.  The Houghton mounting bolt holes are 13 ½” apart. This “In Theory” may provide a ½” pathway around the obstructions to connect up with the drain T and discharge hose.    

•  Another option may be to run the port side drain pan tube around the outside of the kit elevation spacer gasket to mate up with the discharge of the starboard side drain pan (Using the “T” fitting), and then run a single drain line through the Kit elevation spacer gasket and tie this one line into the hull vertical drain tube. 
• Keep the entire drain system outside of the Houghton by intercepting the OTT 1/2" hull drain line and using the drain kit and parts.  Specifically bring the OTT hose through the hull outside of the roof penetration, set the Dometic drain pans and plum them up by running hoses to connect.  

Your thoughts, reservations and suggestions are solicited.

Thank you,  GJ

Edited December 30, 2022 by Geronimo John
Added a fourth option for drain routing.

[Geronimo John]

HOUGHTON 13.5 KBTU Owners:

If you have easy access to your unit, I would very much appreciate knowing the number and location of the condensate drain holes.

thank you,

GJ

[bhncb]

Here are a couple of pictures to help you. I'm afraid it's not going to be as easy as you'd hoped.  On the first picture, I've circled all the holes below the evaporator coil. The orange in the corners are maybe 8mm while the green ones are probably 5. As you can see, the entire bottom pan is structurally molded "plastic".  Looking at the parts breakdown may also help you. 

The second picture shows the height of the roof support bracket. At best it's 10 mm so there's not a whole lot of space underneath the unit. The support bracket has an integrated foam perimeter seal, and compression-seals to the bottom pan when it's torqued down.  Elevating the unit would be much more involved than just using a "spacer gasket".

This particular 3400 is a sacrificial unit I was using, primarily to address your concern. Originally my thinking was to adapt a mini-split condensate pump but the juice didn't seem worth the squeeze. There is a company in OR that fabricates mounting "adapter plates" for these, primarily to accommodate the curvature of Airstream roofs. I thought about contacting them to come up with a design that also incorporated a drain pan system to connected with the Oliver's internal drain tube.  My mental design started to get really complex so I haven't pursued this idea any further at this point.

I've been using the 3400 on my LEII for about three years and don't find the way this unit drains onto the roof to be a big issue. I do tend to avoid high humidity however.

[Geronimo John]

Clark:

Thank you for the great response. Extremely helpful!

I can now understand why we just live with it as is.  The benefit of quiet is 1000X better than the condensate concern. None the less, worth a bit of brain effort to comprehend what I am seeing.  Some brain teasers:

UNIT DRAIN HOLES:

•   It appears that there are 20 each drain holes.  As they are in a pattern by design, I am thinking that not all 20 of them are for evaporator condensate.  If they were, Houghton would need an exotic air containment system for higher pressure Supply Air from the coil than the pressure outside the unit (atmosphere).  Without such a design feature, there would be a LOT of cold Supply Air leaking out those many holes.  It is possible that many of them are drain ports for rain, snow or splash that has entered the condenser coil area or when traveling?  If so, we would not need to capture that rain water.  Just let it flow over the side.    

• If that's the case, can we determine which ones are actually evaporator coil condensate drains?   That could simplify the collection of actual cold condensate.  

 

ROOF SUPPORT BRACKET (RSB):  

• The four main anchoring bolts in the corners of the RSB are on 13.5" centers.  As such, it appears that the RSB OD is about 14 .5" square roughly. 

• Am I correct in assuming that the RSB and the four black "shims together support the unit on our "flat" Ollie roof? 

• As stated the RSB raises the A/C about 10 mm (+/- .4") above the roof itself providing "not much clearance" between the roof and A/C.

• If I were to add a 1" thick spacer over the existing roof penetration (along with 1" spacers over the four black supports (also shown to the right in the white plastic), then .4" of the elevated space would be consumed.  That would leave .6" of clearance to get a .5" drain tube back into the unit.  

Basically we would need a path forward with both of the above ideas to proceed further.  What am I missing?

JPR

[bhncb]

All the holes I circled are open to a drainage trough under the evap coil perimeter. Since the coil is contained in a sealed housing, the fan tends to creates a negative pressure environ so any air leakage should be outside in. It seems to me however that the 8 larger holes at the corners are primarily drains for condensation with the remaining smaller holes providing pressure equalization. 

Since the entire evap assembly is enclosed, there won't be any intrusion by rain or snow. For the exposed section of the unit, drainage is provided by the multitude of holes around the entire perimeter and a few others strategically positioned in the base. 

As far as the support bracket: Your dimension are correct.  I'm not sure what you're referring to as being "four black shiims". The black bracket is a single flat piece and should be shimmed to account for the not-quite-flat roof of the LEII, but there are no shims provided with the unit.. I cut strips out of PVC shim stock but I'd have to do some digging to tell you the thickness I used.

If you wanted to raise the entire unit, I'd look here for a solution. Remember though, your .5" drain tube is ID so figure on 5/8" minimum plus. The tubes would have to pass under the support bracket and achieving an effective seal might be tricky.

Nothing else comes to mind. The standard flex duct that connects the plenum is good for a roof thickness up to 85 mm, so no issues there with this minimal height addition.

[Geronimo John]

Wow X2!

First, these are the four "Black Shims" that I was referring to.  They would be necessary to support the aft end of the Houghton.  Likely are also .4" thick, keeping it at the same level above the OTT roof as the RSB.  It makes sense as the long a/c with the condenser on the aft end is quite heavy.  Combined with the RSB, it appears to provide space outside of the roof 14 X 14 penetration for evaporator condensate drain and pressure relief as you mentioned.  More on this below.

13 hours ago, bhncb said:

It seems to me however that the 8 larger holes at the corners are primarily drains for condensation with the remaining smaller holes providing pressure equalization. 

Some good info with this.  To provide a high % of condensate capture, only the four sets of 2 larger holes would need to be "Captured". 

13 hours ago, bhncb said:

If you wanted to raise the entire unit, I'd look here for a solution.

From their web site:   

"The adapter is curved on one side the match the roof and flat on the top to accommodate the foam seal of the air conditioner.  The adapter also spreads out the weight of the AC over a larger area reducing stress on the roof."

I'm not convinced that a mat, such as above would work for our Houghton.  I am thinking that the Houghton is designed to be supported by the RSB and the four black "Shims" (See Above).  Doing so would, along with some roof side slope, would give the Houghton some clearance for the 20 drain/vent holes to function.  Installing a true flat mat under the entire unit would likely prevent such functions.  Your thoughts?  

If my premise about the RSB and 4 shims carrying by design the weight of the Houghton is not correct, then, once again I have found myself in the wrong tree (Barking up the wrong tree). 

Does the Houghton install instructions require shimming?   

Regardless, I would want to shim the unit to provide additional support as did you.  What did you use?

 

Again, I thank you for your taking the time for myself, and other owners who are interested in buying and installing a Houghton.

GJ

 

[bhncb]

Okay.  I think of them as spacer blocks. The shims I was refer to are necessary between the support bracket and Ollie roof to keep the bracket from rocking side to side, and for establishing a level surface to prevent the bracket from flexing when the unit is torqued down. I though the Houghton instructions noted this but can't seem to find it now. For me, it was just  best-practice.

The pressure I was referring to is the negative pressure created by the evap fan circulating inside air up and through the evap housing. This negative pressure would cause a draw on the larger condensate drain holes, restricting the flow. I believe the series of smaller holes are intended to reduce this effect.  If only the larger holes are captured by your  scheme, there is still a potential for some drainage through the smaller holes. So my question would be: What's the point?

The roof adapter by DIYvans is I suspect machined from a sheet of expanded PVC HDPE aka Starboard.  They are cut specifically for the 3400 outline, with the bottom surface contoured to match roof curvature.  So, it should be no different than if the unit were resting directly on a flat roof. Since the support bracket rests on top of the roof adapter, the underneath clearance for the unit will be the same .4 ".  I would argue that any  adjustment from "level" are best left to routine attitude adjustments made during unhitching and setup. If drainage slope were factored into the installation, one could easily exceed the maximum operating inclination of the unit.

I keep a supply of PVC shim stock around for general use. This is available in various sheet sizes and thicknesses but I have .010 to .060 in four increments. Most of my materials, i.e.stuff like this, are ordered through  Zoro.com.

If/when you do buy one of these, put it on your bench and pop the hood. Compared to the Penguin II, the Houghton is a stunning piece of work.

Edited January 18, 2023 by bhncb
correct product material from HDPE to PVC

[topgun2]

Since I'm not going to replace my a/c until what I've got breaks, I have only scanned the posts above for general reference.

Having said that - you two guys are amazing and I really do appreciate the thought and work that you are/have put(ting) into this project.

Bill

[mossemi]

GJ

This is a picture of the Dometic A/C drain kit instructions.  The 14" square gasket in your picture of the drain kit is used in addition to the existing 14" gasket around the hull penetration with a notch cut into the original to allow passage of the drain tube from the cups to the internal drain tube.  The 2 straight gaskets are stacked at the rear of the base plate to level to unit.

Mossey

[Geronimo John]

On 1/12/2023 at 12:07 PM, bhncb said:

Okay.  I think of them as spacer blocks. The shims I was refer to are necessary between the support bracket and Ollie roof to keep the bracket from rocking side to side, and for establishing a level surface to prevent the bracket from flexing when the unit is torqued down.

Roger we are on the same page, and I prefer your terminology: 

SHIMS: 

The Shims are basically to shore up the support bracket as you stated.  As such, I suspect they are located adjacent to the roof penetration.   

If correct, I have some concern about trailer suspension impacts flexing the A/C base outside of the support bracket (Picture breaking a ruler over your knee.  To mitigate this, how about running a PVC support strip just outside of the two upper and lower gold circled drain holes (See Clark's large color picture above showing 20 drain holes).

Such PVC support strips would provide support to that A/C, and if sealed to the roof could also divert the condensation from flowing down the side windows.  We would need to take into consideration that the OE2 roof slopes at the rear of the trailer.  Likely these shims would need to be flexible to track the roof down sloping camber at the rear.  For the rear most area, due to the downward roof camber, their height could be augmented with additional shims to still provide weight support.  I envision these shims as being about an 1 1/2" wide, and adhered directly to either Ollie.       

DOMETIC SPACER BLOCKS:

Mossey:  Thanks for the post.  It confirms what Clark and I were thinking.  The spacer blocks provide altitude for the 1/2" drain to pass back into the roof penetration, and also support for the aft end of the A/C.  Nice to have the picture! 

On 1/12/2023 at 12:07 PM, bhncb said:

As far as the support bracket: Your dimension are correct. ...

Since the support bracket rests on top of the roof adapter, the underneath clearance for the unit will be the same .4 ". 

As evaluated above, the clearance available for the drain tube is less than the tube OD.  As such, I'm thinking we would want to use the Dometic kit spacer blocks plus an additional 1/4" thick spacer to gain that height for the two drain tubes trip to the hull drain tube.

CONDENSATE DRAIN PANS:

This would allow using two Dometic drain pans on each side of the trailer connected via a "T".  I had previously considered running one side around the roof penetration, but as soon as I recalled that trailers are not always perfectly level.  Tilt.  If I had gone with one penetration and all four pans interconnected, eventually the if the curb side was low, the water would not flow up hill to the street side pans and then to the drain below.   So  my rethink is four drain pans, two penetrations just as Dometic and Ollie did.  That said, the path in the Ceiling plenum zone will have to take into account the duct within a duct design of the Houghton.

Comments and thoughts very much appreciated.

GJ

PS:  If any of our Houghton DYI installers still have their Dometic Drain Kits, I would love to acquire them to mock up our approach.  If so, please give me a PM.  

Thanks 2X!

 

[Geronimo John]

duplicate post deleted

GJ

Edited January 19, 2023 by Geronimo John
Duplicate post deleted. GJ

[SeaDawg]

I'm guessing,  as early adopters, we're in the first set.

[Geronimo John]

 

19 hours ago, SeaDawg said:

I'm guessing,  as early adopters, we're in the first set.

For sure. 

Would be interesting to know if there are any other Houghton owners with a Set 1 (Fan turns off with the compressor cycling) and when they purchased theirs.

[Geronimo John]

 

19 hours ago, SeaDawg said:

I'm guessing,  as early adopters, we're in the first set.

For sure. 

Would be interesting to know if there are any other Houghton owners with a Set 1 (Fan turns off with the compressor cycling) and when they purchased theirs.

But this post and a few above would be better included into SteveCr's thread "Houghton Humidity Issues" thread.  

CJ

[bhncb]

On 1/17/2023 at 10:38 PM, Geronimo John said:

Comments and thoughts very much appreciated.

First off, I’ve edited my earlier post with regard to the material DIYvans uses for their roof adapters. I was having a hard time resolving their price versus material and fabrication costs with HDPE. Turns out their adapters are actually machined from UV resistant expanded PVC, which obviates another question I had as to color availability. (Any color you want as long as it’s black). Also, I'm changing some terminology to reflect Houghton parts list names.

The idea for a modified design of the DIYvans roof adapter is still in the back of my mind, but this issue doesn’t concern me enough to justify the cost to produce. If Houghton comes back with “Oh yeah, we have a fix for that”, I’d probably redo my installation however.

As I mentioned previously, capturing just the larger drain holes would only provide a partial solution. Assuming the size and shape would even work,  mimicking the Penguin II by attaching four of those drip pans would involve modifications to the Base for fasteners. It would not be as simple as just running in some self drilling screws. But there's more....

The biggest problem I see with your plan to use an additional roof gasket is the difference in mounting schemes, Dometic versus Houghton. The Dometic A/C is soft-mounted with a foam seal establishing a cushion between the fiberglass roof and metal base pan. The A/C fasteners are tightened down to compress this seal until a specified clearance between the roof and A/C is achieved. Adding the additional seal from the drip pan kit just increases this dimension.

In contrast, the Houghton uses a hard-mounting scheme in that the Roof Mount bracket directly contacts the fiberglass roof (sealed with liquid sealant) and the A/C Base is compression-sealed on top of the bracket. The A/C fasteners are torqued to a specified value that ensures sufficient clamping force between all three components. If the Roof Mount bracket was isolated from the roof with a compliant foam seal, the required clamping force would be near-impossible to achieve or maintain resulting in an unreliable compression-seal. I'm not sure this scheme lends itself to your broken ruler scenario but enlighten me. 

If you were really committed to pursuing the Dometic drip pan solution, I suppose you could cut a riser for the Roof Mount bracket out of one-inch HDPE and notch the top for the drip pan tubes. Sealing for leaks might be iffy though. Might give you something to think about though.

Regarding Shims: I cut nearly full length pieces for each side of the Roof Mount bracket and  adjoining end pieces to-length as required. Lengths and widths are actually just short of the bracket flange dimensions so edges would be concealed by silicone sealant. Stock thickness would be as-required, 0.010 or 0.020 maybe? I’d recommend checking each installation first though because there could be enough variation between Oliver’s upper shell moldings that shimming wouldn’t be necessary.

As far as runoff, I have both awnings and this issue is no different than when the Penguin pans would occasionally overflow. Condensation just rolls off the sides and down to the awnings, which channel it to the rear corners aft of the windows. I suppose some of that stick-on window guttering might work for situations without an awning.

Be sure to include pictures.👌

 

 

 

 

[Geronimo John]

As many of us know, its real hard to plan an Ollie mod  when you will not even see your Ollie for the winter. Let alone from 4,000 miles and eight months as is our case. 

Prior to your most recent note, I was not aware that the Dometic Drain Pan spacer blocks are compressible.  This shoots a huge hole in all of the above. 

I thank you for taking the time to mentor this effort, but it appears to have been "a fools errand". 

Hopefully you will fare better on the Set 1/Set 2 issue.

GJ  

[Geronimo John]

Well, the "fool" is on a mission now.  Will be traveling to the mainland later this week and will be installing my Houghton 13.5 unit .

Per BHNCB's picture and other posts, some of the condensate is evaporated off, and at times some drains out of some (depending on trailer leveling) of the below marked holes.  I would like to add some EDPM rubber sealing material in a tall "U" shape around these holes. Would have the open end towards the rear of the trailer. Idea is to set up slightly nose high and let it drain towards the back of Ollie.  

For the Ollie DYI installers of this unit, can you advise about how much curvature there is outside of the drain holes relative to the mounting height of the A/C?  Basically what thickness should I be looking to seal to do so? 

Thank you,

Geronimo John

[SeaDawg]

Hey, @Geronimo John, and welcome back to the contiguous 48!

I hope your install goes well. Keep us posted. 

I think a few folks just used ez rv rain gutter to channel the water away.

We did nothing on our 11.5.  We use it so very seldom, figured we'd jack up the nose a bot and let the condensate run, when necessary.