Installing hydronic heater

[ChrisN94]

Hey, first time posting here, I’m based in the UK and looking for pointers on installing a D5 hydronic heater to my 144 (MWB) MB Sprinter W906 that I’m in the process of converting to a camper.

I want to use the hydronic with a plate heat exchanger and a heat exchange blow box to provide hot water and hot air.

I’m looking to install the heater unit in the engine bay and T off the vehicle coolant, but I’m not certain on where the best place to T off from is and struggling to find anything definitive online.

Any help would be much appreciated!

 

[Kajtek1]

From what I see the best spot for those heaters is in passenger seat pedestal.
I was considering D5 for my conversion, but than calculated it too expensive and too risky.
So I went for cheaper air heater for cabin heat and electric heater for water.

 

[GeorgeRa]

D5s are installed by factory behind the driver side front wheel. I installed mine there. You could have threaded holes there. See the picture of factory unit and mine, same place.

 

[ChrisN94]

D5s are installed by factory behind the driver side front wheel. I installed mine there. You could have threaded holes there. See the picture of factory unit and mine, same place. View attachment 143047View attachment 143048

Thanks a lot for the pics! Mine is a RHD am I right in assuming you mean the drivers side on a LHD? Do you know where the factory fitted ones pick up and return the engine coolant?

 

[GeorgeRa]

Yes, it is on the left side of the vehicle. My system is not integrated into vehicle coolant, I have custom made overflow tank under the hood. Coolant loops: overflow tank > D5 > Isotemp calorifier > back to overflow tank. Search this web of the connecting to vehicle coolant. Hein has Isotemp marine water heater (calorifier) under the hood connected to engine coolant. I used Isotemp instead popular flat plate heat exchanger for hot water to have instant source of hot water, well insulated Isotemp keeps high temperature at least for 12 hours.

I found another picture of 2 D5s installed by factory.

 

[gltrimble]

Do you know where the factory fitted ones pick up and return the engine coolant?

My factory installed D5 on my 2017 intercepts the coolant flow upstream of the heater core. The D5 discharge is split to the heater core and an auxiliary heater or a water heater before returning downstream of the heater core. I chose to put my Isotemp marine heater in series flow upstream of the heater core to maximize the heating of the hot water. I also added an engine bypass valve/circuit to allow the majority of the hot coolant to return directly to the D5/Isotemp bypassing the cold engine.

 

[ChrisN94]

Thanks for the replies, that’s really helpful!

 

[Pochiba]

We're looking at installing the same heater to our new Sprinter. In our previous van we used a Bosch electric water heater, but this time around we're looking at different options and love the idea of heater water off the van's engine.

Does anyone know if this would void the Mercede's warranty?

Also, I saw someone referred to this water heater as "risky" and I was wondering if you could expound upon that? The idea of a hydronic heater is new to me so I still have much to learn.

Thanks in advance!

 

[GeorgeRa]

The only risk I can see is hot water direct exposure. Thermostatic valve can automatically prevent hot water reaching faucet or shower head by mixing hot and cold water preventing this possible problem. Water temperature could reach engine coolant temperature which would be dangerous. My Isotemp water heater came with this type of valve. I preferred independent water heating loop so I don't need to run the engine to heat water.

Heating water with engine coolant is very popular in the boating world. Mostly marine heaters (calorifiers) are used. I have not seen use of flat plate heat exchangers in the marine world. Any marine water heater includes insulation so it is a reservoir of hot water which can last for 12 hours or more.

 

[avanti]

Does anyone know if this would void the Mercede's warranty?

No aftermarket modification affects your warranty in any way. That is against federal law.
Of course, if your installation provably causes something else to break, that repair would be on you. But, this is an exclusion from the warranty, not a "voiding" of it.

P.S. -- hydronic heaters are the best.

 

[vancation]

Almost understanding the system D5>Isotemp>coolant (engine or 2nd coolant tank). My question is how do I heat the isotemp tank from engine heat without tapping into the engines coolant directly?

 

[GeorgeRa]

Mount a flat plate heat exchanger in the engine compartment and connect it to engine coolant. Run D5 coolant via through the other side of the heat exchanger using D5's pump or another pump. It should be reasonably simple and safe.

 

[Carl a van]

would anyone have a diagram of the factory cooling system?

 

[Franny]

I just added a 30 plate heat exchanger with some switches, relays, and anti scald valve to our T1N. I rebuilt the Espar which had electrical shorts and corrosion.
The only testing so far has been a ten minute hot shower. I was concerned that the heat transfer would have a hard time keeping up with demand but was surprised to see it did.
The fresh water tank water was about 50f and the engine was off and cold. Outside temps were in the mid 30’sf. It took about ten minutes for the old dw5z to get coolant up to 180f.

 

[Corbury1492]

I'm doing a new van build - 2019 VS30 144.

Looking for hot water (shower and dishes) inside the van.

I'm torn between:
1. Bosch electric HW with 500+Ah lithium and a 2200W Inverter (samlex 2212)
or
2. Isotemp slim connected directly to engine coolant loop - with electric supplement with 400Ah of AGM.

I have the AGM - I would need to buy/build the lithium batteries.

Apart from the cost implications which are nearly equal (lithium battery DIY vs. isotemp) - how hard and risky is the plumbing of the isotemp from the engine to a possible isotemp location behind the driver's seat in a kitchen cabinet. Planning on 4 season use in cold climates - so thinking all water inside the van. Also, do not want to compromise drivability of the van - no warning lights, coolant leaks, etc.

(Adding a D5 would even make this whole thing more expensive - so hoping to avoid that.)

Thoughts?

Thanks,

C

 

[RVBarry]

Apart from the cost implications which are nearly equal (lithium battery DIY vs. isotemp)

Hi, this doesn't sound right for 500aH @12VDC...
100aH 3.2V LiFePO4 cells are usually over $120USD, and you need 20 of them, and a BMS (and inverter).
And some way to charge them!

Isotemps are $600-800USD

 

[avanti]

I'm doing a new van build - 2019 VS30 144.

Looking for hot water (shower and dishes) inside the van.

I'm torn between:
1. Bosch electric HW with 500+Ah lithium and a 2200W Inverter (samlex 2212)
or
2. Isotemp slim connected directly to engine coolant loop - with electric supplement with 400Ah of AGM.

I have the AGM - I would need to buy/build the lithium batteries.

Apart from the cost implications which are nearly equal (lithium battery DIY vs. isotemp) - how hard and risky is the plumbing of the isotemp from the engine to a possible isotemp location behind the driver's seat in a kitchen cabinet. Planning on 4 season use in cold climates - so thinking all water inside the van. Also, do not want to compromise drivability of the van - no warning lights, coolant leaks, etc.

(Adding a D5 would even make this whole thing more expensive - so hoping to avoid that.)

If you aspire to 4-season usage, IMO you would be insane not to use some sort of fuel-driven heater. Do the BTU math.

BTW: How are you going to deal with cold-weather storage of the lithium batteries when the van is not in use? You will need either constant shore power or else remove the batteries during winter storage. Otherwise they risk freeze damage in frigid weather.

 

[gltrimble]

Hi, this doesn't sound right for 500aH @12VDC...
100aH 3.2V LiFePO4 cells are usually over $120USD, and you need 20 of them, and a BMS (and inverter).
And some way to charge them!

Isotemps are $600-800USD

I believe the OP is comparing cost of one 100ah lithium with the Isotemp.

 

[Corbury1492]

I was planning to order the:
EVE 3.2v 280AH lifepo4 cell:
Quantity:8pcs
Price:US$85.5/pc
Shipping cost & time: US$265 (by Sea transportation, door to door, including tax and custom,25-30 working days around.)
Total price: 85.5*8+265=US$949
+ 2 * 120A BMS from overkill = $230
so call it $1400 total including the Bosch, housing, etc. That's 560Ah-ish (actually more like 540Ah).

The isotemp is about $1000 + some plumbing and fittings + install. Maybe total $1200-1300?

Isotemp Slim Square Stainless Steel Marine Water Heater 16L, 4.2 gallon 115V/750W with mixing valve

The Isotemp Slim Square Stainless Steel Marine Water Heater comes with brushed stainless steel cover as well as innovative internal design. It achieves highest capacity by optimized installation of the engine water heat exchanger as well as the immersion heater. Isotemp Stainless Steel Marine...

mmarineonline.com

They aren't too far apart.

But - is there a good "how-to" on doing this inside a VS30 van?

thanks,

C

 

[GeorgeRa]

I was planning to order the:
EVE 3.2v 280AH lifepo4 cell:
Quantity:8pcs
Price:US$85.5/pc
Shipping cost & time: US$265 (by Sea transportation, door to door, including tax and custom,25-30 working days around.)
Total price: 85.5*8+265=US$949
+ 2 * 120A BMS from overkill = $230
so call it $1400 total including the Bosch, housing, etc. That's 560Ah-ish (actually more like 540Ah).

The isotemp is about $1000 + some plumbing and fittings + install. Maybe total $1200-1300?

Isotemp Slim Square Stainless Steel Marine Water Heater 16L, 4.2 gallon 115V/750W with mixing valve

The Isotemp Slim Square Stainless Steel Marine Water Heater comes with brushed stainless steel cover as well as innovative internal design. It achieves highest capacity by optimized installation of the engine water heat exchanger as well as the immersion heater. Isotemp Stainless Steel Marine...

mmarineonline.com

They aren't too far apart.

But - is there a good "how-to" on doing this inside a VS30 van?

thanks,

C

What is your battery recharging plan?