I've just installed an SMB stock hot water heat exchanger. It's in the standard location under the rig below the sink on an RB50. It's up and running and works great!
My question is on draining the exchanger for winter. Where are all the shutoff valves supposed to go to drain this sucker? I'm hoping to plumb it so the exchanger is drained and I can still use the cold water in the van. No problem putting a valve at the bottom of the exchanger, but there needs to be a shutoff for the cold water inlet, probably under the sink. What about some way to let air in so it will drain? How's that set up?
Anybody got a stock one they can check for me??

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Scatter
You can be anything you want on the Internet,
it amazes me that so many choose stupid....

2007 RB50, 6.0
K1WGB

I learned the hard way. Just putting a drain valve is not enough to protect the flat plate from freezing and possibly rupturing. Here is a post of how I installed it inside my van and put valves to fully bypass it and I did put a valve to let air in at the top to quickly flush all the water out of the heat exchanger.
viewtopic.php?f=13&t=6018&hilit=plumbing+redo
This set up has worked flawless for several years now and nothing have frozen since it has been moved inside. But I'm sure that even if you leave it outside, this draining and bypass system will really help.
There is a valve on the supply line and the exit line. Then there is a drain valve at the bottom of the unit and the air supply valve at the top. So to bypass the system, 2 valves are closed and 2 valves are opened. All of these are 1/4 turn valves. It takes about 5 second to bypass the whole unit.
Let my know if you need any clarification on how this was put together.

Cheers,
John

Thanks for the link John. I forgot all about it. I thought about an inside install but am really using all the under sink space and thought that since SMB put so many under the rig that I decided to give it a try. I planned to install pretty much the same valves you did, but was wondering what the stock setup consisted of.
I'll wait a bit to see if I get any other responses before I start the work. But, no matter what, if I want to be able to use the cold water while the exchanger is drained, I will pretty much need the setup you have. I'm guessing that the way SMB plumbed it was for total non use winter storage.
Thanks again.

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Scatter
You can be anything you want on the Internet,
it amazes me that so many choose stupid....

2007 RB50, 6.0
K1WGB

I moved mine under the sink for winter duty. Works well, and doesn't freeze when winter camping.

viewtopic.php?f=13&t=8495&hilit=heat+exchanger

Z

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'06 RB50 SMB Diesel

https://www.tomsinclair.net

Moving it inside will really help keeping it from freezing. But I understand your need for every square inch of space. As long as you can find room under the sink for the bypass valves, I'm sure you will be fine. Two good things about putting the valves inside.
First you won't have to go outside at night to evacuate the system or in the morning to charge it. It's darn cold at those times of the day and you will most likely have to be reaching under your van to get to the valves. And if you're driving around in the snow, things get very messy down there.

The second thing is if you can evacuate the system from inside. That will most likely mean none of the waterlines that go out side will have water in them. So in the morning when you recharge the system, everything should flow. The biggest problem I had when our heat exchanger was outside was the few inches of waterline that were exposed to the outside temps would freeze. Then the ice would crawl up inside the van. That would somehow block our plumbing system and we would have no water at the sink until afternoon, even if we drove around. By keeping the valve as far from the floor as you can, this should prevent the waterlines from pulling the freeze inside.
Good luck,
John

I'd love to have the exchanger inside, but I see a real problem with a 200 degree exchanger in my booze cabinet. But, it sure would be a lot easier than all those valves.

The way it is, I can plumb all the valves in to isolate it, but am worried about getting it to drain even with a separate valve to let air in at the top. There is a check valve in the top of the exchanger as it comes from SMB. I don't know if it's air tight, but if so, it would prevent air from coming in and all the water from draining.

You guys that have it inside, how hot does the cabinet get?

Hummm, actually, the only time we use hot water is for a shower. Maybe I could mount the exchanger inside and put a shut off valve in the coolant line so I can control when it's hot? Now I need to check if shutting off the coolant will cause other problems....

__________________
Scatter
You can be anything you want on the Internet,
it amazes me that so many choose stupid....

2007 RB50, 6.0
K1WGB

Check out the link to my post one more time, viewtopic.php?f=13&t=6018&hilit=plumbing+redo
The first part of me moving it inside is the coolant bypass valve (I call it the worst case scenario valve). With three valves I put together a system that I can completely stop coolant from getting to the heat exchanger without stopping the flow of coolant in that line. I can also partially open all thee valves and somewhat control the maximum temperature of the water.
A little farther down the post is a pic of the heat exchanger covered with a three sider insulated box that REALLY cuts down on the heat in that cabinet. It is a little warmer then the cabinet next to it but no where near hot.

Cheers,
John

Thanks for a little more clarification John. I didn't realize that you could stop the coolant from going through the exchanger. I think I'm convinced on putting it under the sink. I also checked my coolant lines and they are just spliced into the van heater lined with a Tee, so the coolant is not forced to go through the exchanger to also go to the van heater. So, I should be able to put a valve under the hood in the line to the exchanger to stop the flow there. That would take less plumbing. But, if I need to pull it apart in the future, there will be more of a mess without shutoffs right by the exchanger. More thinking to do....

__________________
Scatter
You can be anything you want on the Internet,
it amazes me that so many choose stupid....

2007 RB50, 6.0
K1WGB

Well, just to close this out, I did move my heat exchanger to inside under the sink. My thanks to Zeta for the heads up on the bulkhead fittings and to John for the photos and info on his modification. Everything went smoothly and now I don't have any water lines outside of the rig. I did put a 90-degree shut off valve in one of the coolant lines, under the hood, that goes to the heat exchanger. That stopped the water flow and now there is no heat under the sink unless I open the valve. This works for us as the only time we use the hot water is for a shower so 99 percent of the time the valve is shut and I have no heat in my booze cabinet. Thanks again guys for the info on this and the boost to get me going on a much needed project.

__________________
Scatter
You can be anything you want on the Internet,
it amazes me that so many choose stupid....

2007 RB50, 6.0
K1WGB