Layout plan.

PaulDavis

Member
Report: we've already spent 2 months in the gray, mild damp of southwest England. Yesterday I was down under the bed (looking for a lost item) and staring at the walls near the floor. Our conversion is insulated with ezcool, thinsulate and reflectix, topped by 1/4 ply sealed on both sides with 3 coats of marine polyurethane. We keep the van warm with an Espar D2, and often but not always run our exhaust fan overnight when sleeping.

There is extensive condensation and even a little mold down there. The wooden walls down near the floor are cold enough for condensation to form on them; ditto for the batteries and everything else near the floor level including a very small part of a wheel well that was left un-insulated (covered in QuietCoat but no thinsulate).

Hopefully, southern Spain for 6 weeks will be enough to get us dried out.

On reflection I should probably have used the D2 to drive an air delivery system that actually heated the lower part of the van more extensively.

Still, the level of damp in the UK is something you have to see to believe. If things can survive this, they can survive anything, I suspect (maybe the tropics would still be an issue).
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Report: we've already spent 2 months in the gray, mild damp of southwest England. Yesterday I was down under the bed (looking for a lost item) and staring at the walls near the floor. Our conversion is insulated with ezcool, thinsulate and reflectix, topped by 1/4 ply sealed on both sides with 3 coats of marine polyurethane. We keep the van warm with an Espar D2, and often but not always run our exhaust fan overnight when sleeping.

There is extensive condensation and even a little mold down there. The wooden walls down near the floor are cold enough for condensation to form on them; ditto for the batteries and everything else near the floor level including a very small part of a wheel well that was left un-insulated (covered in QuietCoat but no thinsulate).

Hopefully, southern Spain for 6 weeks will be enough to get us dried out.

On reflection I should probably have used the D2 to drive an air delivery system that actually heated the lower part of the van more extensively.

Still, the level of damp in the UK is something you have to see to believe. If things can survive this, they can survive anything, I suspect (maybe the tropics would still be an issue).
You are bringing a good point about the condensation versus not uniform heat distribution from the D2. I noticed on the rear lower side of our sofa bed some rust on the black oxidized 8020 bolts so I do have some problem with condensation. I could add a 4’ hydronic baseboard heater self-regulated by a thermostatic valve to my winterizing coolant loop. I am finishing the D5 installation so at least I can add a couple of T fittings for a future install. Purging air should be easy because my overflow tank is located high on the engine firewall.
George.
 

PaulDavis

Member
We have particularly poor air circulation for this purpose. Our cabinet designs and the items under the bed (water tank, battery, water heater, storage) all conspire to really minimize air flow at this level.

My parents' commercial Murvi (based on the Fiat Ducato aka Dodge Promaster) has a D2 with two separate outlets to carry air to different parts of the van. If I had to redo this, I'd find some way to make the D2 blow air into distribution tubes that carried the air at floor level all the way around the van, and just rely on convection to get the heat into the upper half.

We're snug and comfy in the van because most of us is > 1' off the floor. But down at that level, things are still pretty chilly - chilly enough that water vapor will condense right onto the wooden walls.
 

Midwestdrifter

Engineer In Residence
I found it aiming my D2's output at the center of the van floor helps to circulate air and prevent cold spots. Of course if I have the front cab open to the van it's almost pointless because of all the cold air that rolls off of the windows and doors.

In really cold weather I sometimes wish that I had installed a heated floor.
 

casmith32

Member
I'm installing a D5 rixen setup as well - any suggestions on what the best option is for the in-floor heating loop ? I presume I'd have to raise the floor up 1" or so to make room for the tubing ? Need to understand the layering as well here...what tubing, parts, etc are recommended ? I think Irontent would have some feedback here ? Not sold on the idea but it is compelling - need to understand the cost/benefit ; complexity vs more simple...

This conversation couldn't come at a better time as I'm prepping flooring, and insulation, ventilation, etc. Thinking I'll try to at least run heating loop through the wheel well cabinets, to get some heat in there around the wheel wells; added benefit is the water tank is in the wheel well cabinet too - thoughts ? would it be enough heat to mitigate this uniform heat distro around the walls/wheel wells ?

You are bringing a good point about the condensation versus not uniform heat distribution from the D2. I noticed on the rear lower side of our sofa bed some rust on the black oxidized 8020 bolts so I do have some problem with condensation. I could add a 4’ hydronic baseboard heater self-regulated by a thermostatic valve to my winterizing coolant loop. I am finishing the D5 installation so at least I can add a couple of T fittings for a future install. Purging air should be easy because my overflow tank is located high on the engine firewall.
George.
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
I'm installing a D5 rixen setup as well - any suggestions on what the best option is for the in-floor heating loop ? I presume I'd have to raise the floor up 1" or so to make room for the tubing ? Need to understand the layering as well here...what tubing, parts, etc are recommended ? I think Irontent would have some feedback here ? Not sold on the idea but it is compelling - need to understand the cost/benefit ; complexity vs more simple...

This conversation couldn't come at a better time as I'm prepping flooring, and insulation, ventilation, etc. Thinking I'll try to at least run heating loop through the wheel well cabinets, to get some heat in there around the wheel wells; added benefit is the water tank is in the wheel well cabinet too - thoughts ? would it be enough heat to mitigate this uniform heat distro around the walls/wheel wells ?
Sorry, I don't have Rixen, as far as I know only Irontent on tis forum has heated floor. I have homebrewed Airtronics D2 / Hydronic D5 / Isotemp combination which I found to be less expensive than Rixen.

George.
 

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Midwestdrifter

Engineer In Residence
1" should be plenty. Using 3/8 tubing (PEX, coppper etc) should work just fine. If you can fine some reasonably priced heat spreader plates, that would improve the performance. Routing slots in the subfloor will also probably be necessary.

You will also want/need some insulation under the tubing, or most of your heat will end up outside the van. Even 1/4" foam would cut the heat transfer by 3/4.


I am not 100% sure, but I believe user jackbombay used heater hose to hydronically heat his floor at minimal cost. You might drop him a PM.
 

Roodster

Member
Paul, did you insulate under the floor? I used 1 inch polyiso, in between wood battens, but I left the corrugations open at the front & back. I think airflow under a floor is as important as insulation. My house here in the UK is 200 years old, the ground floor is laid just above the soil, air bricks on the outside. When the wind blows the air comes through the floorboards like an air blade hand dryer, timbers are still good, not a trace of damp in the house, but I freeze to death in the winter probably preferable to moldy damp. Airflow is key to damp, maybe a butterfly type hole on the back door just above the floor would pull that espar air down?
 

PaulDavis

Member
Paul, did you insulate under the floor?
I did, thought not that much. I don't think the problem I've seen is related to this as much as the lack of air circulation though. The areas where it is worse are ones that are really, really cut off from air flow. So for example, the lower walls in the very back of our 170 are as far away from the D2 as you can get, but they are open to the air: no condensation. The areas where air is "trapped" by cabinetry, tanks, batteries etc. are the problem ones because they just stay cold. I've seen cases where the D2 thinks the van is at 64F but the temperature sensor on a battery says 43F.
 

Roodster

Member
Apologies to GeorgeRa if I'm getting OT, here in the UK condensation is one of the big issues in a van. Most people believe in a damp/air proof membrane between inner & outer walls. Im starting to believe that this may be nigh on impossible with a sprinter van. I took as many steps as possible to achieve this but one screw hole will equalise the RH from the outside to inside. It may take time but it will happen, what happens then is that it will take just as long to dry out again. I don't have the answers, but if I'm not using my van then dry storage is very important in a humid part of the world like the uk. One last thing, when I started using 80/20 type profile, a friend who is an ex Royal Navy engineer, came over to help with the electrical work. He took one look & said what am I doing?, I'm going through steel with zinc bolts & fixings into aluminium. He refused to do any work on the van unless I used stainless fixings throughout. PITA, but the UK is a very damp & grey place at this time of year, & as he said, at least I''l be able to undo those bolts in 4 years time!. Thanks for your patience George. :)
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Apologies to GeorgeRa if I'm getting OT, here in the UK condensation is one of the big issues in a van. Most people believe in a damp/air proof membrane between inner & outer walls. Im starting to believe that this may be nigh on impossible with a sprinter van. I took as many steps as possible to achieve this but one screw hole will equalise the RH from the outside to inside. It may take time but it will happen, what happens then is that it will take just as long to dry out again. I don't have the answers, but if I'm not using my van then dry storage is very important in a humid part of the world like the uk. One last thing, when I started using 80/20 type profile, a friend who is an ex Royal Navy engineer, came over to help with the electrical work. He took one look & said what am I doing?, I'm going through steel with zinc bolts & fixings into aluminium. He refused to do any work on the van unless I used stainless fixings throughout. PITA, but the UK is a very damp & grey place at this time of year, & as he said, at least I''l be able to undo those bolts in 4 years time!. Thanks for your patience George. :)
I agree that sealing insulation is practically impossible, water vapor will penetrate through mostly permeable RV materials and the speed of penetration will depend on material permeability, and RH on both sides. One of the reason I picked Thinsulate was to speed up the humidity equalization process.

I am slowly replacing the black oxide screws with SS ones.

George.
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
The final big project of finishing my van is the time dragging D5 installation. As always there are some stumbling blocks, in this case it was finding an appropriate overflow/fill tank which I could mount in the left side of the engine bay to minimize hoses length, being above D5, and have one coolant drain for the whole system.

Finely decided to make one and this tank will be rather expensive. Tank volume is just shy of 5L so I am OK with required 3-4L plus some air space. The tank, with a level monitor, will be mounted on the side of the battery tray with a good insulation in between. I am making a provision for a possible addition of the convection heater, just 2 plugged tees.

The winterizing loop will have to 2 x 1/2" dia 4' copper tubings attached to the SS fresh water with high temperature SS tape with some insulation on top. To protect plumbing I will run coolant hoses together with fresh water hoses.

The winter throttle valve is intended to increase the coolant flow through winter loop during cold days.

George.
 

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Graphite Dave

Dave Orton
If you decide to add the convection radiator near the rear doors, I have available a small truck cab radiator that has a 12 volt fan.

Was removed when I gave up on the plan of using the Mercedes Espar heater to warm the van.
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Just curious, why the 2 connections at the bottom to the overflow tank?
Eberspacher coolant loop requires a minimum volume of coolant to prevent D5’s from short cycling potentially reducing its life. Minimum volume data is different from different sources, from 2.5 gal to 3-4l so I picked 3-4l one, actually almost 5l.

The overflow tank performs 3 functions:
1. Expansion tank
2. Main system volume which is why coolant flows through
3. Fill station.

In my case the overflow tank is connected in parallel, if D5 will short cycle which I doubt, I can increase the flow though the overflow tank by restricting the flow in the main loop.

George.
 

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GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
If you decide to add the convection radiator near the rear doors, I have available a small truck cab radiator that has a 12 volt fan.

Was removed when I gave up on the plan of using the Mercedes Espar heater to warm the van.
Thank you Dave,

I am thinking about a convection based hydronic heater. It is simple to build or get a built one baaed on 1/2" Cu tubing like the one on the picture, no forced air just a lot of fin's area. No current draw!

Cheers,

George.
 

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GeorgeRa

2013 Sprinter DIY 144WB, Portland OR
Suspect that the rate of heat transfer would be better with the forced air fan.
Agree, but this would be my auxiliary heater helping the main heater the Aitronics D2 which is under the passenger seat. So no much heating would by require from this heater. For a full hydronic heating a force air heat exchanger would likely be a must unless you have the Irontent's floor heating.

George.
 

GeorgeRa

2013 Sprinter DIY 144WB, Portland OR

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tgregg

Active member
In my case the overflow tank is connected in parallel, if D5 will short cycle which I doubt, I can increase the flow though the overflow tank by restricting the flow in the main loop.

George.
When I installed my D5 and Isotemp I used a parallel system like figure 5 in the Espar manual. I also had 2 radiators for cabin heat in series with each other but in parallel with the D5 and the Isotemp. I had a valve in series with radiators that I could close in the summer when no cabin heat was required.

Wouldn't it be necessary to move one of the hoses going to the expansion tank to the other side of the D5 or Isotemp to achieve a parallel connection? Or am I misreading the diagram?
 

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