Heating system does this make sense?

[Markusbc]

Hello, just in the final phases of installing the heating system. Wondering if my system makes sense or if there are any changes that should be made.

Heat source is a x45 proheat diesel coolant heater or the engine when driving.
Here is a quick sketch of the system.

Any thoughts and input highly appreciated.

just realized its hard to see on the picture.

basically it consists of 3 loops:

1. one non toxic antifreeze loop that will be heated by the proheat then goes to a marine hot water heater after that there is a bypass valve for summer use so it only heats up the hot water. When heat is required inside the bus it goes through a heat exchanger to heat loop 2.
There is a second heat exchanger that can be brought into the loop to heat the engine with the proheat but also to let the engine heat up the hot water and the inside radiant heaters as well as the heated floors.
after that there is a buffer tank to reduce short cycling and a expansion tank.

Questions here do i need a secondary coolant pump to circulate loop one when the proheat is off but i want the engine to heat up water and indoor heating (i feel like i do but if there is a other way to make this work that would be great)

Loop2:
heat exchanger from loop 1, goes to a manifold, for heating the floors and to heat the indoor radiators (the fans will control the heat output) once they collect again via manifold 2 a coolant circulating pump keeps the system flowing, again a buffer tank and a expansion tank and back to the heat exchanger.

Is the buffer tank needed here also expansion tank?

Loop3:
heat exchanger via loop 1 to engine.

[Markusbc]

After some thoughts I think I can eliminate loop2 and incorporate it into loop one with a summer bypass valve so that the heated coolant only heats up hot water and not the heated floors and radiant heaters. It would eliminate one buffer tank and one expansion tank.

[somewhereinusa]

Just some thoughts. My system has been in use for 7 years. I have a similar although it has more loops for heat.

I put valves in to isolate the water heater. I have NEVER used it and have never ran the boiler in the summer to heat water. If I'm parked I have electricity. If the engine has been running it gets heat from the engine.

I did not isolate the engine from the heat, just don't see the need.

I don't think you need more than one expansion tank and overflow in the whole system. If the valves are closed to keep heat out of the floor/radiators that water isn't going to expand. When it is open the main tank will take care of it.

I don't have a buffer tank. In my research 10 years ago none of the systems had one. Short cycleing has not been a problem.

For circulation when the boiler is off I hacked into the wiring so I could turn on the boiler internal pump. I'm not familiar with the proheat. I have an Espar.

I have four zones all for heat. Each room/zone has a thermostat that controls a pump for that room. Each room also has a heater with fan. Each fan has a manual switch as well as a snap switch sensing water temp. The fan will not come on if water is not warm so it won't blow cold air. When the thermostat turns off a zone when the water temp gets below a certain level the fan shuts off.

I think if you don't incorporate some way of controlling water flow to your heat it will get too hot in the room. Just turning off the fan isn't enough. When things are up to temp I turn all of my fans off unless it's really cold outside.

Dick

[Markusbc]

Thank you for your thoughts.
Do your loops connect via heat exchangers or one big loop with valves creating smaller loops?
Do you use solenoid valves or mechanical ball valves? So if I understand that correctly if all of the loops are running (heating) it is one big system with one expansion tank. If a sea gets warm enough the pump turns off for that area or does a valve close? Do you have 4 pumps one for each loop?

[somewhereinusa]

Here is a drawing of my basic layout



My valves aren't indicated they are all manual ball valves. In reality I have never closed one so this diagram is correct.

To control heat the pumps turn on/off controlled by a thermostat. The zone that has the original heater in it is controlled by a switch on the dash, not a thermostat.

Here is a VERY simplified diagram showing the basic idea.



It is basically built like an automotive cooling system including a 4lb radiator cap. Be sure your marine water heater has a blow off valve. Mine has never opened but better safe than sorry. Also make sure to inclued bleed valves. I learned the hard way.

An Espar heater has an internal pump. I used it to bleed the system and I also use it to circulate water in the main loop when I am using heat from the engine. In my system the four loop pumps are the same pump that the internal Espar has.

[Markusbc]

Ok thank you.

I was thinking of having one pump and then valves that open and close each zone. Instead of each zone having its own pump. In your opinion would that work?

[Markusbc]

just to give context, i measured the draw of the coolant pump and it is about 4 amps, my thought was to use one coolant pump and use either solenoid valves or motorized ball valves to control the flow in the hope to reduce the power consumptions.

3 coolant pumps at 4amps each plus the heater itself that draws 7,5 amps that stacks up to a decent constant draw when the heat is on.

[cadillackid]

many of the motorized ball valves are 2 wire spring return so they will have a decent amoutn of current draw when in the motorized position. I run nornally closed valves in my bus but havent measured the current for the open position. 3 wire valves which are power open power close would be less of a constant current draw.



my 12kw coolant heater uses 5/8 lines going to it, i did a series-parallel flow for my bus heaters. (I dont have floor heaters just fan coils).. that pump will handle having all but 1 zone on.. I think if I reduced the flow into my right side hesater, which is a straight 1 inch in / out and is parallel to the main valves although somewhat far from the coolant heater pump. i could run all my zones on that little pump..



the bus has a larger 1 inch heater pump. which can run in unisoon with my coolant heater if i want to heat the engine too. in my case heating the engine is important as it has no glowplugs so if im in a situation parked with no shore power and its below zero im in a possible no-start situation.. so being able to have. the coolant heater also heat the engine was important.. much less cumbersome than havign to drag out a generator or waste my batteries to heat the engine.

-Christopher

[Markusbc]

Originally Posted by cadillackid

many of the motorized ball valves are 2 wire spring return so they will have a decent amoutn of current draw when in the motorized position. I run nornally closed valves in my bus but havent measured the current for the open position. 3 wire valves which are power open power close would be less of a constant current draw.



my 12kw coolant heater uses 5/8 lines going to it, i did a series-parallel flow for my bus heaters. (I dont have floor heaters just fan coils).. that pump will handle having all but 1 zone on.. I think if I reduced the flow into my right side hesater, which is a straight 1 inch in / out and is parallel to the main valves although somewhat far from the coolant heater pump. i could run all my zones on that little pump..



the bus has a larger 1 inch heater pump. which can run in unisoon with my coolant heater if i want to heat the engine too. in my case heating the engine is important as it has no glowplugs so if im in a situation parked with no shore power and its below zero im in a possible no-start situation.. so being able to have. the coolant heater also heat the engine was important.. much less cumbersome than havign to drag out a generator or waste my batteries to heat the engine.

-Christopher

yes same here i do want the engine coolant to be able to be heated.

currently all my lines are 1" (lines from the bus) or 3/4" (coolant heater) and the hydronic which is 3/8" and 1/2".

I like the 3 wire idea and just control them with a arduino or raspberry pi. I am in the process of making a hub for the bus out of a raspberry pi that will control also the heat and valves. I have been able to eliminate the timer that came with the proheat and control that part via pi in conjunction with some temperature sensor.

Christopher i know you are the resident electronics/programming wizard. Have you had any success using raspberry pi to read the engine data for a dash without using a 3rd party proprietary hard and software?

[cadillackid]

I read my engine data with a pi. but i do use a hardware interface device.. I felt it unnecessary to go through the process of reinventing the wheel. which is that of building the interface itself. . I use a BB-electronics J1708 / J1939 to RS232 box which does the heavy hitting of talking to the vehiclke, dealing with the special highs and lows of the modifed RS485 line and the special timings that J1708 / J1939 require.



if you want to build your own interface then you can start for building a circuit with the ELM325 chio for J1708 or the ELM327 chip for J1939.


your engine talks in J1708 your allison talks in J1939.. for relay control there are 2 relay boards im playing with, both USB. one is a nice DIN rail style DenKovi USB16 relay module, and the other is a Numato Lab USB relay module..



not sure which one ill go with yet.. the DIN rail unit seems beefier.



internet for remote control at a distance im using a MikroTik LTAP mini that creates a secure Tunnel into my home network..



member 'BrokeDown' got me started into using websockets for writing the software to actually web control this stuff with my phone or computer.. Back-end stuff was always my forte, ot so much User interface.. I was oriiginally look at using openHab home automation software to handle the UI side but its overly complex for what I need to do..



of course I just replied with a mixture of things im doing in 2 different busses.. my DEV / covid-social-distance. bus has no J1708 or J1939 as its all mechanical.. however it does have the internet and the 12kw Coolant heater im controlling along with a couple valves and blowers.



I ran power from my house batteries up to my dash so i could run several devices off the house batteries which are recharged by the alternator or my victron shore charger so this way I can run my heater and heat-blowers, pumps with the engine off and not risk accidentilly killing my starter batteries.. my air-conditioners, defrosters, and regular bus lights are run off my main starter batteries. sicne they are items i onkly use with the bus on. on a cold day havign the 2 blowers i wired to the house batteries can easily overcome the 12kw of heat that the coolant heater makes so theres no reason for any more heaters on that circuit.



on my red bus the ultimate goal is to eliminate the mechanical switches and have a glass cockpit fully, thus why I want the fancy UI for touch screen control of my bus switch-panel and remote of its 5kw webasto.

[Markusbc]

Originally Posted by cadillackid

I read my engine data with a pi. but i do use a hardware interface device.. I felt it unnecessary to go through the process of reinventing the wheel. which is that of building the interface itself. . I use a BB-electronics J1708 / J1939 to RS232 box which does the heavy hitting of talking to the vehiclke, dealing with the special highs and lows of the modifed RS485 line and the special timings that J1708 / J1939 require.



if you want to build your own interface then you can start for building a circuit with the ELM325 chio for J1708 or the ELM327 chip for J1939.


your engine talks in J1708 your allison talks in J1939.. for relay control there are 2 relay boards im playing with, both USB. one is a nice DIN rail style DenKovi USB16 relay module, and the other is a Numato Lab USB relay module..



not sure which one ill go with yet.. the DIN rail unit seems beefier.



internet for remote control at a distance im using a MikroTik LTAP mini that creates a secure Tunnel into my home network..



member 'BrokeDown' got me started into using websockets for writing the software to actually web control this stuff with my phone or computer.. Back-end stuff was always my forte, ot so much User interface.. I was oriiginally look at using openHab home automation software to handle the UI side but its overly complex for what I need to do..



of course I just replied with a mixture of things im doing in 2 different busses.. my DEV / covid-social-distance. bus has no J1708 or J1939 as its all mechanical.. however it does have the internet and the 12kw Coolant heater im controlling along with a couple valves and blowers.



I ran power from my house batteries up to my dash so i could run several devices off the house batteries which are recharged by the alternator or my victron shore charger so this way I can run my heater and heat-blowers, pumps with the engine off and not risk accidentilly killing my starter batteries.. my air-conditioners, defrosters, and regular bus lights are run off my main starter batteries. sicne they are items i onkly use with the bus on. on a cold day havign the 2 blowers i wired to the house batteries can easily overcome the 12kw of heat that the coolant heater makes so theres no reason for any more heaters on that circuit.



on my red bus the ultimate goal is to eliminate the mechanical switches and have a glass cockpit fully, thus why I want the fancy UI for touch screen control of my bus switch-panel and remote of its 5kw webasto.

i have been playing around with embedded wizzard for the UI.

You are right i dont have time to reinvent the wheel, I will look into the hardware that you mentioned. I agree a glass panel similar to a tesla would be pretty great. I was going to use esp8266 and esp32 to do the weblink. Also to control things wireless.

I just read about a prius inverter pump that only draws 1amp at full load, that might work as a booster pump for the hydronic.

[DrDanger]

Originally Posted by Markusbc

...
I like the 3 wire idea and just control them with a arduino or raspberry pi. I am in the process of making a hub for the bus out of a raspberry pi that will control also the heat and valves. I have been able to eliminate the timer that came with the proheat and control that part via pi in conjunction with some temperature sensor.

I am also interested in doing something like this with a Raspberry Pi, but I haven't take the time to learn how to do it yet. One thing I noticed as I was trying to decide how I wanted to build my system was that solenoid valves are expensive! (at least ones meant for hydronic systems)
I think it might actually be cheaper to use a legit manifold and the zone actuators that go with them. (see thread here) Have you found some reasonably priced solenoid valves? I'm still open to the idea, just haven't been able to find the right components to make it happen.

[Markusbc]

I think i am also going the 3 wire motorized ball valve route. But yes i have looked into the legit manifolds. Tempting especially because of the flow indicators but the actuators consuming power constantly while heating the floor seems a bit much in terms of power consumptions.

On a different note, i did a bit of research and realized the oxygen barrier pex tubing max. out at 200F. One thing i have not seen on all the skoolie hydronic floor heating diagrams is a mixing valve to loop some of the cool water (return after running through the loops) back into the hot water to reduce the heat to a more pex friendly temperature. My heater turns off at 185F automatically but i what about when driving the bus? Is the loss through a heat exchanger enough to keep it below 200? Also 200 seems a bit toasty for the floors lol.

[Markusbc]

i saw in your instagram account that you are adding a wood stove, which one if i may ask. Been looking at some as well, mostly for additional heat and preferable it has a glass front , which is always nice to look at.

[cadillackid]

when we did a mixture of floor heat and baseboard or fan-forced heaters we either had to run separate boilers, or us a separated heat exchanged system which meant hokey setups when it came to expansion tanks and such or we did Bleed-valves .. for the floors it was important to have uniform temperature across the floor, so we ran high volume pumps.. sometimes parallel flow within the same room for large rooms..



this was in the 90s so PLCs were used (these were high end homes where only one bioiler was desired anbd more precise control).. it worked out well.. the floors were always stage 1 in a room, stage 2 would be the baseboards or the fan forced coils.. the outside temperature dictated the boiler temperature unless a stage 3 was called in which case the boiler ran up against its max setting until stage 3 was satisifed.. this was a quick warmup feature for an unoccupied house where the whole system was dead coild.. the PLC didnt know the setpoint delta on the thermostats other than we used 3 stage stats in rooms that were designated as "main".. it worked really well..


for commercial buildings a separate boiler was used and all floor loops on that boiler had a preset temperature.. (based on whatever building control the site had,. usually a johnson, barber coleman or honeywell building automation control).. I wrote algorithms to get the most comfort and efficiency out of the systems.. as much as i could do in the mid 90s...