Diesel hot water systems

#47
Gentlemen,

Could someone help me out with the controls on the Wabasto hydronic heaters. It seems they are timer driven. I could not find a thermostat on the corporate web site, although, is listed as a heater option with the Espar heaters.

Charlie, your 5 kw is the thermotop correct? How is yours set up for control?

mnb
 
#49
I have a espar 5kw that I added a thermostat to.

Using the wiring diagram, I located the wire (yellow, I think) from the timer to the furnace that made it run.

I placed a single pole double throw switch in that line that I can use to connect either the timer to the furnace control line or a battery operated thermostat I purchased from Home Depot.

That way I can use either the timer or the thermostat to control the furnace.

The thermostat should be battery operated instead of using voltage from the furnace so it can supply 12 volts to the furnace control lead.

And I set the "swing" on the thermostat to it's maximum of three degrees so the furnace runs longer and less frequently instead of shorter and more frequently.
 

egn

Adventurer
#50
I use a thermostat in the separate heating loop, which is connected to the webasto loop by a heat exchanger (see drawing at previous page).

So the webasto is free running just with it's internal thermostat. But AFAIK it has a control input which can be used to turn it on and off by a thermostat.

This setup has the advantage that the warm water heater always gets the full heat of the webasto, even when there is no heat for space heating required.
 
#51
I use a thermostat in the separate heating loop, which is connected to the webasto loop by a heat exchanger (see drawing at previous page).

So the webasto is free running just with it's internal thermostat. But AFAIK it has a control input which can be used to turn it on and off by a thermostat.

This setup has the advantage that the warm water heater always gets the full heat of the webasto, even when there is no heat for space heating required.
That's the setup I'm leaning towards, as it allows the (espar in my case) to better regulate the variable burner. If the unit is turned on and off by air temp it can't directly know the heat deficit.

The water heater always in the loop stores BTU's to allow for a quick warm-up ("quick" being a relative term in Alaska)
 
#52
Does anyone know a vendor that makes a diesel tankless hot water heater. It should be similar to a propane or natural gas TANK-LESS water heater, except diesel generates the heat. I want it to be a "stand-alone" on demand heater that is NOT integrated with the main engine cooling system and not connected to any heat exchanger.
 
#55
Hmm. Do those have a wait time for hot water? Seems like diesel can't fire up fast enough to provide instant hot water.

Just glanced at their site. Seems like it's no different that hot water systems that many have built using an espar and heat exchanger to heat water.
 
#57
Hmm. Do those have a wait time for hot water? Seems like diesel can't fire up fast enough to provide instant hot water.

Just glanced at their site. Seems like it's no different that hot water systems that many have built using an espar and heat exchanger to heat water.
The video they have on the Class C information page goes into a good bit of detail on the hot water system and claims it's nearly instant and is capable of a 55F delta at 1gpm. For that you'd need the hot water system already fired up, but supposedly it uses less than 0.2gph of diesel. My guess is the startup time is pretty low given the components used from what I've seen. Less than a minute.

So yeah, you probably don't want to leave it running if you're leaving the camper for many hours, but you probably can leave it running for much of the time you are at your camper.

I've been looking for exactly this kind of system for my new van build I'm starting soon and the only thing that sucks is that these guys are 3k miles away from me. I've got an email off to them to see if they sell any kind of kit. Hoping so. Even if their system is a mix of OTS parts, it's a very good mix of OTS parts.


--Donnie
 
#58
Does anyone know a vendor that makes a diesel tankless hot water heater. It should be similar to a propane or natural gas TANK-LESS water heater, except diesel generates the heat. I want it to be a "stand-alone" on demand heater that is NOT integrated with the main engine cooling system and not connected to any heat exchanger.
Quick search.... first thing that popped up is EverHot http://www.suremarineservice.com/everhot-tankless-on-demand-copper-water-heater.aspx apparently it attaches to a Webasco or Espar
 
#59
So yeah those are definitely misleading in saying that they are on demand. They are only on demand if the system is up to temp from the engine or from the espar or webasto. Basically the same thing everyone builds on their own using an espar and a marine hot water heater or heat exchanger unless I'm missing something.
 
#60
The system from Rixen is sold as a kit. The installation manual is on their site, but it's...sparse. He says they will have an installation video in a couple months (don't wanna wait that long). But they'll sell the complete kit for about $5200. I'm currently....mulling. That's a lot. The Espar at the heart of the system is only $1600, but it's the other stuff that adds up.


--Donnie
 
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