Bus down by the river

[inhof009]

Originally Posted by o1marc

Dude, you're in the USA, temps are in F, not C. On hindsight, I should have run a loop through the small bathroom. I'm not saying I run them full hot, but I've read others have said it didn't get so hot it couldn't be run wide open. I will test with mine to see what works. The heaters I'm using are HON brand, Chinese knock off.

Lol, yeah, I know it's freedom units, but both the manifold and my potential heater (drivworld, also Chinese knockoff) talk about temperature in C so it's easier just to list them in that for the purpose of making sure it's not too hot.

That's a pretty tidy setup you have! Did you cut those water lines with a router? What is the lowest temperature you can handle?

[o1marc]

Originally Posted by inhof009

Lol, yeah, I know it's freedom units, but both the manifold and my potential heater (drivworld, also Chinese knockoff) talk about temperature in C so it's easier just to list them in that for the purpose of making sure it's not too hot.

That's a pretty tidy setup you have! Did you cut those water lines with a router? What is the lowest temperature you can handle?

I did use a router to run the lines in the rigid board. I have no idea of the operatin yet as it is not completed. Although today I bought a new hose to fill the system with, seemed all my house hoses had the exit end cut off. I'd like to fill it and test for leaks, but will probably not do anything more until I get back home tis weekend. I have to be back Monday for an orthopedic surgeon appointment. Seems I need 2 complete reverse shoulder replacements, fun.

[Mattj]

Im new here. It's great to hear someone in my area doing a bus. If you need a hand let me know. I will send a PM

[inhof009]

Originally Posted by Mattj

Im new here. It's great to hear someone in my area doing a bus. If you need a hand let me know. I will send a PM

Matt,

I replied to your PM, but I'm unsure if you received it. At this time, not much work is being done (will post in a moment as to why), but I'll let you know when I need your help!

In addition, you might be interested in joining the facebook group we have for our area:
https://www.facebook.com/groups/2363317743942748/

[inhof009]

So my "winter break" started today and will last through February. However, I'm planning on making a trip to MN for Christmas, which means I need insulation and heating prior to then. I have the spray foam ready for the interior, but the minimum temperature is 60F and the weather hasn't been cooperating just yet, so I'm stuck sitting on my hands. I dislike it.

In the mean time, I'm thinking about the classic "rear heater coolant lines" rerouting that is frequently talked about here, but instead of a simple loop back, I want to hook up an interchange where the coolant is routed through the floor, engine, and a coolant heater, all interchangeably. Needless to say, this is a bit daunting to consider, and I've been unable to find much information regarding this. Here's my plan, and I could definitely use a sanity check on it.

Current state of the lines (yes, it's kinked, but the valves ahead of this are all off so not like it matters. Also, that's not rust underneath it but brown colored primer. Poor choice in hindsight.):

Top is 1" hose coming from the engine, and bottom is 1/2" hose going back.
Here's my plan:

I'm planning on using entirely brass fittings and valves, because of the temperature and pressure. I've priced out everything, and it's looking to be about $300, so I just wanted to be sure it'll work properly before I drop that much on it. All of the parts are unfortunately female threads, so I'll be connecting them all with 1" close threaded brass nipple.

Does this make sense? Does it look like it'll work and hold up to the wear and tear?

[Mattj]

No I didn't get the PM. Did you check locally for someone to come spray. I was wondering what way was cheaper. I will check out the Facebook link

[inhof009]

Originally Posted by Mattj

No I didn't get the PM. Did you check locally for someone to come spray. I was wondering what way was cheaper. I will check out the Facebook link

Matt,

I did check locally, yes. 7 companies I called, 5 said they would call me back, 1 actually did and quoted me $3500.

I bought the kit for $650... One kit should do a good job, but I might decide to add another on top later, depending on how well it insulates (and money).

[Mattj]

I have been surprised with this area. Something's are hard to get and sooner cost more around here then other places do.
Have you laid out any electrical or run pipes yet before you insulate

[dimoimo]

If you're trying to reduce your lines from 1" to 1/2", you'll have a problem with flow rates for the 1" lines returning to the engine past the 1/2" radiant loop. You'll also have problems with coolant flow based on your design. The more 90 degree bends you add to your coolant loop, the more pressure reduction you'll have along your flow path. The path with highest flow rate will be the path with the highest pressure




The first image shows the flow of your current design, the second has added controls. The added controls would be 2 check valves (dark red) and an extra shutoff (yellow). These will help maintain proper flow, but you will still have issues with pressure reduction through the radiant loop. On top of that, you may have issues with the water pump in the engine keeping up with the added volume of coolant.

To solve this, you may be able to add a circulator pump in line, but I think you'll be hitting the upper range on pumps that operate within the coolant temperature range coming straight from the engine (~200-250F).

Most setups I've seen that run off of the engine coolant use a plate heat exchanger between the engine coolant and a separate loop with a dedicated pump. You can even add a diesel coolant heater in your dedicated radiant heating loop to heat the space without the engine running. Just a thought.

[inhof009]

Originally Posted by Mattj

I have been surprised with this area. Something's are hard to get and sooner cost more around here then other places do.
Have you laid out any electrical or run pipes yet before you insulate

I am intentionally waiting until after insulation to run electric and plumbing. The way I see it, if I ever want to add or replace wires or pipes, I want access to them, so I'll put them outside of the insulation.

[inhof009]

Progress! I picked up the plumbing and assembled it. A few leaks existed, so more teflon tape, some more tape, and tightening every connection has led from this:

to this:


Fired up the bus, ran it for a while (I also added some anti-gel since it's getting cold around here), and turned on the booster pump and the brass got warm quickly, so I'm calling it a success! The above picture is after I shut it down, so the paper towel is there to see any more leaks if they happen.

I was feeling pretty good, so I checked and the weather had indeed cooperated! The temperature of the walls and of the air inside the bus was warm enough to insulate. 2-3 hours later:



Obviously, there are a few unfinished spots. When I was working on the bottom panel in the back left, I ran out of tank "A" and apparently still had tank "B" going. I didn't realize immediately, so some of the stuff back there will need to be re-done. I am going to let it fully cure for a day or two and then re-evaluate. I obviously need to cover those bare areas, but I might have a use for touching up a few spots in other areas, so I might go with a 200BF kit to cover the bare spots and have some left over for touchup.

[Native]

It is great to see progress like that!

[dimoimo]

I posted a couple days ago but it seems it got deleted.

Looking at the flow of your diagram, you're going to run into a few issues.




The bottom portion (below the green line) is fine. The issue you'll run into is reduced pressure without any flow controls between the shut off valves. I've added 3 that will help regulate your flow better.



The main issue you'll have even with the correct controls in place is a pressure differential for the coolant returning to your engine. Going from 1" diameter to 1/2" diamater may cause issues with engine temps and extra strain on your water pump.

To combat this, many setups use a brazed plate heat exchanger to run isolated radiant heating lines with a dedicated circulation pump. With the isolated loop you also have the option of adding a coolant heater in line to heat your space when the engine is not running. You don't want to be idling in the cold months all the time just to get your floors warm.

[BlackJohn]

Nice alteration to your heater line plumbing, simple worked.


John

[inhof009]

Originally Posted by dimoimo

If you're trying to reduce your lines from 1" to 1/2", you'll have a problem with flow rates for the 1" lines returning to the engine past the 1/2" radiant loop. You'll also have problems with coolant flow based on your design. The more 90 degree bends you add to your coolant loop, the more pressure reduction you'll have along your flow path. The path with highest flow rate will be the path with the highest pressure




The first image shows the flow of your current design, the second has added controls. The added controls would be 2 check valves (dark red) and an extra shutoff (yellow). These will help maintain proper flow, but you will still have issues with pressure reduction through the radiant loop. On top of that, you may have issues with the water pump in the engine keeping up with the added volume of coolant.

To solve this, you may be able to add a circulator pump in line, but I think you'll be hitting the upper range on pumps that operate within the coolant temperature range coming straight from the engine (~200-250F).

Most setups I've seen that run off of the engine coolant use a plate heat exchanger between the engine coolant and a separate loop with a dedicated pump. You can even add a diesel coolant heater in your dedicated radiant heating loop to heat the space without the engine running. Just a thought.

It's strange that I'm seeing this now and not when you posted it originally, but I very much appreciate your feedback!

First, I would like to address the red lines you drew. They were all correct, with the exception of the horizontal ones at the top of the page. You drew them because my drawing looks like a T on each side, but it's not that at all; it's actually a poorly drawn hose barb. I plowed ahead with the original design (can be reworked, though), and you can see it installed here:

Obviously, real world picture looks better than my drawing.

You bring up good points about the flow, though, which I would like to discuss with you. Easiest one to tackle is there circulation pump. My bus already has one coming off the engine upstream of this brass, so that one's all good! And the coolant heater I'm installing has a pump.

Your comments about reducing from 1" to 1/2" intrigue me. My thought on this was that one of the 1/2" is sucking and the other pushing, so the net flow in and out will be the same, with the portion of 1" pipe between the two 1/2" reducing tees will have reduced flow. I will have hot water circulation pumps for each zone off the manifold, so the flow should be equivalent for all zones that are flowing. Those that aren't "on" might have some flow due to turbulence, but I'm not too worried about that and will have shutoffs if I want them truly off.

What do you think of my design with more details and a real-life example instead of a bad drawing?

[Ronnie]

I like all the nice looking brass. My only comment would be the 1/2' plugs, I might have been inclined to keep them 1" as is the rest of it, to allow more flow if needed. I reality it will most likely work just fine. I am assuming they will be tapped into later for another circuit?

[inhof009]

Originally Posted by Ronnie

I like all the nice looking brass. My only comment would be the 1/2' plugs, I might have been inclined to keep them 1" as is the rest of it, to allow more flow if needed. I reality it will most likely work just fine. I am assuming they will be tapped into later for another circuit?

Ronnie,

Yes, the 1/2" plugs will be tapped into for the hydronic floor heat. In hindsight, it might have been best practice to have those be 1" as you suggested and have the manifolds go from 1" to 1/2". However, I think the flow will be low enough overall that it won't be a problem. Future directions, though, if I have issues.

[inhof009]

Originally Posted by Ronnie

I like all the nice looking brass. My only comment would be the 1/2' plugs, I might have been inclined to keep them 1" as is the rest of it, to allow more flow if needed. I reality it will most likely work just fine. I am assuming they will be tapped into later for another circuit?

I did some sleeping (or, rather, reading up on this forum late at night instead of sleeping) on this topic last night. In hindsight, I think you're more right than you let on. Firstly, most of the manifolds I'm looking at have 3/4" in/outlets at a minimum, so I would go from 1" to 1/2" back up to 3/4". Kinda makes more sense to just go 1" down to 3/4".

Looking around more and thinking more, I'm leaning toward adding a mixing valve. I see a lot of people talking about their engines usually running 160-180 F at normal cruising, but the cooling fan doesn't kick on until about 210F. At that point, if I don't drop the temp any, I'm risking the pex lines in the floor. Since I don't want to deal with breaking a pex line in the floor (likely while driving), I'm thinking more and more that a mixing valve is a good idea. If I decide to do that, I can use the nice stainless steel manifold from pexuniverse I linked earlier and just keep the temperature below 158F. AND that manifold has 1" in/outlets. So more and more points to NOT dropping to 1/2" being a good idea.

When I get the coolant heater, I have to open up and rework the brass anyway, so I'll change out the reducing Ts from 1/2" to 1" at that time. I've been able to lose minimal amounts of coolant each time, but with the extent of that reworking, I'm going to drain (and save) the coolant to avoid losing so much this time.

[inhof009]

Updates. I took a gamble on a chinesium coolant heater, and so far it looks like it's going to pay off. Instead of the $2-3k webasto, I was able to get an equivalent one for about $500. I have fired it up in my yard and everything looked good, but I wasn't able to get it to run a full cycle because the exhaust pipe almost started the grass on fire.

Unfortunately, the heater did NOT come with an installation or user's manual. I was able to figure out the basic operation, but higher level stuff will take some poking around first.

I used that last 200BF of insulation and hit the last few panels and had plenty left over to clean up the rest of the bus, plus add some more to the thinner parts.

I ran into an issue with mounting the heater that I still haven't fully solved, but I have some ideas. Once it's mounted and hooked up, I'll cycle it and make sure it works well. After that, I'll build a box with angle iron and left over sheet metal to protect it from road wash and debris.

On the topic of webasto vs chinesium for diesel heaters, I'm still not sure. We'll see what ends up happening with my heater over time before I call it a success.

[ted@campbycanoe.com]

Nice work!

What brand insulation did you use?

We're in a similar boat here: too cold for foam, but I'm hoping to prep everything over the winter and let foam fly when the weather warms up!