New owner of Vintage Bus 1980

[freds]

Making progress of my DIY hydronic system and was able to run a test on Sunday and will first post what worked!

I filled it slowly with water today from a low point and it has 20 gallons of storage and topped out somewhere around 23 gallons which seems right.

Absolutely none of the PEX connections that I put together using the expansion tool leaked!!!



Fired up my diesel heater and observed the following behavior:

1. It sat there for a bit of time while I think it did its startup sequence of warming up the glow plug, testing water flow and fan speed.
2. It started clicking the pump loudly which muted down as the pump filled with fuel.
3. Exhaust pipe output a little bit of white diesel smoke.
4. Internal fan speed ramped up and the exhaust started to roar and the output fluid pipe was about 170 degrees (no muffler at this time).
5. When turned off it went through a shutdown and cool down cycle for about 3-5 minutes before fully shutting down.

So I believe that the diesel boiler is functional.

[freds]

1. Some of the manual connections that i made had slow drips during the water testing phase.
2. The air purge valve didn't seem to work at all, might have had it adjusted wrong.
3. I think there was problems with the check valves that I used in my design, maybe not enough flow rate to fully close.
4. The diesel heater cycled up and down in heat output which might be:

a. Maybe it was programmed with non-standard settings because it was used warm a generator in an arctic settings and hey if the cold coolant is 80 degrees, job is done. I do have a diagnostic kit that I have to figure out how to use with this heater.
b. Check valve was more and likely not fully closing and allowing re-circulation between the input and output to the diesel heater. Maybe I should do a standalone test with a tank of water. Dang, I gave away a rain barrel last month that I could have used for this...
c. Replace check valve for diesel heater with a automatically closing valve as soon as the heater is commanded to start; forcing all flow to pass through the remote diesel boiler.

5. Circulation/stir pump seems to keep loosing prime as I mounted it too high up.


Anyway I was able to bring the storage up to about 110 degrees though the target was 160 degrees, but hey it was a first run!!!

[Fratto]

Thanks for keeping us posted. Good luck!

[chiplamb]

1. Some of the manual connections that i made had slow drips during the water testing phase.
2. The air purge valve didn't seem to work at all, might have had it adjusted wrong.

1. Some of the manual connections that i made had slow drips during the water testing phase.
2. The air purge valve didn't seem to work at all, might have had it adjusted wrong.

Fred, by air purge valve do you mean a bus air source to blow out water lines i.e. for winterization? If so please keep that air source valved out reliably (i.e. a manual valve) since there's quite a history of electro-mechanical air/water valves failing (BB) and flooding brakes/suspension full of water.

[Joe Camper]

I have never seen a prevo with fresh water in the air system or ever heard of it. I'd be amazed if that's the function of the purge. It's for flow not winterizing.

[freds]

The air purge valve is for removing air from the coolant. Using water right now until I am confident that the system is functioning correctly and then will make 50/50 with food grade glycol for freeze protection.

[freds]

The last day and half have been a big wiring project for the DIY hydronic heating system that I have been working on.

Anyway, here’s the layout that I came up with, bit more of a rat’s nest then I originally planned, but hey working on getting it wrapped up and done!!!



Also, I am running out of bay wall space. So, I pre-wired everything up on a one-foot square board with extra-long wiring leads and mounted it to the ceiling of the plumbing/electrical bay.

Your basic Raspberry Pi driving two eight channel relay boards. I went with a left over SSD drive for long term reliability; as the typical SDCard can wear out in 2-3 years or sooner depending on the write cycle frequency. Plus the SSD drive is faster...

The functions that it is currently controlling is:

• Bedroom heater zone pump.
• Bathroom heater zone pump.
• Kitchen heater zone pump.
• Living room heater zone pump.
• Front bays freeze protection pump.
• Rear bays freeze protection pump.
• Stir/circulation pump.
• Pump for Engine preheating and thermosiphon heat recovery.
• Pump for Generator preheating and thermosiphon heat recovery.
• Diesel Boiler remote on/off.
• Electric ball valve to force flow through the diesel boiler when it is on, bypass when off.
• Temperature sensor for hydronic tank output.
• Temperature sensor for Engine coolant, thermosiphon heat recovery monitoring.
• Temperature sensor for generator coolant, thermosiphon heat recovery monitoring.

I still have four relays left over and could add another eight-channel relay board for $10.00 before I max out the Raspberry Pi. All told this could be duplicated for around $120.00

Once all the hardware is installed then it’s software time!!! Something I do everyday in my day job.

Starting with a simple manual over-ride web page with simple touch buttons for each relay function.

Software wise in the long term will be smart scheduling and Alexa voice control integration. Which is easy to do with Internet of Things Node Red software.

[Gil_J]

Nice work!

[Chad Speer]

That looks like a fun project. What diesel-fired heater are you using for your system?

[JCarrollJr]

Hey Fred,
For some reason, I was just rereading your very first post and something jumped out at me that I didn't notice the first time that I read it. You mentioned waiting for your AAA RV add on to become effective. You might want to check on that RV add on. For years I've had AAA and wouldn't be without it and for years I had the RV Plus addition and felt very secure. At some point in time in a conversation with them they made me aware that the RV Plus option didn't apply to a bus. Only a camper. I don't remember the exact limitations on the RV Plus, but it didn't cover a Prevost based motor coach. I dropped the RV Plus option and went elsewhere for roadside breakdown towing coverage. Again, don't remember all of the details but you might want to check on it.