Can you use the factory Espar block heater for hot water?

[kcshoots]

There is a MB factory option that will extend the engine hot water further back to the B pillar for use connection to an air/water heating system, it's option H88. I have ordered that option on my next van to be received in 2-3 months. I plan to use the coolant water and connect into an Espar D5 hydronic heater to heat the coolant and distribute that thru a hot water tank and heat exchanger for potable hot water before the glycol loop is returned to the engine. With some control valves I'll control the water flow to prevent it from going back to the engine when the engine is not running in order to not loose the heat to the engine block, but this hot water will be readily available as warm cooling when starting the engine. The Webasto and Espar hydronic heaters maintain water temps between 160-180F.

Inside the van the glycol hot water is passed thru fan coil(s) to transfer the heat to air to heat the living space. This system will pre-heat engine water as well as heat the van and potable hot water with or without the engine running. Cost is about half of the SMB route (no cooling) and will consume 2-4 amps at 12VDC when running, and very little diesel. Fans and pump will speed up and down as needed. All system components are below the van except for the fan coil(s) in the van. One or two are needed depending upon air desired distribution. I am using two for better temperature evenness as well as control (heat from or rear) and also with control of fan speeds and coil selection for a very quiet and efficient system that can run thru the night at low with very little noise and temperature controlled by a programmable t-stat. The heater will cycle on and off as needed, which will be little with the thermal capacity stored in the hot water tank and loop.

The factory heater options as others have said will not run below 40F without modifying the ambient temperature input of the van to the Webasto heater. This has been done fairly easily to control them to run below any desired temperature.

Either a Wabasto or Espar hydronic heater will function the same, and yes, each of these options put out 17,000 BTUs, more than enough for our vans. In comparison, the Espar D2 or Webasto 2000 diesel air heaters put out between 2,000-4,000 BTUs and those adequately heat up the van and keep it warm at freeing temps, so 17,000 BTUs is enough to heat the block, potable water and air. The block prefers to be at about 190F when running while potable hot water and hot air are best at around 100F, so there is a lot of thermal capacity in these units for this purpose. We use tempering valves so that the 180F potable tank water is controlled to the faucet(s) at about 100F, a safe and normal temp. The factory units are designed to heat the engine coolant and block very quickly at freezing or sub-freeing temps. We are just looking for comfort.

Let me know if you want more details. This system can be installed by my company or others. Happy to help.

[Wrinkledpants]

I thought about that briefly before we ordered the van. There were a few downsides to that setup for our purposes. Maybe you have some insight into this as we're still in that window where we can make changes.

1. With the factory Espar, you obtain ECU control for the aux heater function. Since a big portion of our use will be high-alpine winters, having that extra heat boost while the engine is warming up is nice. This is mostly automatic, at least in so far as turning on the Espar after the engine is running to help the coolant heat up faster. I know you could have someone jump in the back and fire up the D5 to accomplish the same function, but then someone would have to shut it off.

2. Factory Espar is part of the 5 year 100K engine mile warranty, which we anticipate we'll extend us 7 years to 175K miles.

3. With the factory block heater and a D5 for coach, we keep the engine coolant system closed and under warranty. If lose coolant, we've lost the ability to keep the coach warm. If you have two separate systems, then the D5 could still operate to keep things warm, or idling the engine would do it. For us, it's mostly about keeping the water tanks from freezing.

If you have any pros cons in comparing your setup with our needs, that would be great.

[kcshoots]

The factory aux heater will heat up the engine coolant faster than without it in cold temps, and consequently this will provide engine heat faster. It's a good option to have even if not used very often. If you want heat without the engine running than you will need an air heater or separate water heater (or another option) and if you want hot water, than you will need a water heater. The water heater can provide all three: space heating, hot water and engine heating, pre-start up or during operation. The hot water heater (Espar hydronic D5 or Webasto Thermo Top C) is the lowest cost if only one option is selected to provide all three. You are right that the factory heating unit is simple as pushing a button in the dash and automatic from there, but also only good for warming up the engine sooner and when outside air is below 40F. The hot water heaters can be so simple to turn also with a button in the dash or elsewhere, and also automatic as well, just depends on the programing and control to give you the operation you want.

Redundancy is nice, that is the main premise of what I engineered and operated for the first 20 years of my career. Having separate systems is nice for redundancy but it is also more expensive, heavier, involves more maintenance and how important is it to have two heating systems? The likelihood of either one failing is very small and if it did, you would keep your jacket on, doesn't stop you from traveling forward. If you only want engine heating, than the factory heater options are great. If you want heating without the engine running but no hot water, the diesel air heaters (e.g. Espar D2) are great. If you want hot water (with or without space heating) than you need an aftermarket water heating option, which there are many depending upon fuel choice, shore power, and amount of heat or hot water is needed. If you want hot water, than there is little to no value to the factory or space heating options. For you there is some value to redundancy, but really think thru a redundant system for heating really necessary when all of these system options are very dependable. The aftermarket water and space heating options can run manually at any time you want, regardless of ambient temp or engine running, via thermostat control and even remote control, unlike limitations with the factory options.

In my current van that I am about to convert, I am installing a combination hot water& space heating system that can also pre-heat the engine coolant as well as use the engine coolant to heat the hot water. They are separate systems yet tied together to leverage each other. In this build I also chose the factory cold weather package (CO8) for the heated seats. The additional cabin insulation is probably pretty worthless with me also adding my own cabin insulation that will be far more effective. The CO8 option also includes the smaller (17k BTUs) aux coolant heater. I seriously thought about pulling out the heated seats to save $500 on the aux heater and insulation included in this package, but I too think that there will some minimal value to a more automatic rapid engine heating, although I will see after some use with this current build if this redundancy is not worth the ~$500 add.

[trib]

The Espar website now shows a new Hydronic S3 Economy engine pre-heater. Maybe it's the same "pre-heater booster" that is an option for the Sprinter. It uses gas or diesel or a few other fuels. I will consider it for use in a Transit. There's a great video and diagrams (technical brochure). Compared to the D5, it is not an air heater or water heater. It is a coolant heater for preheating the engine when the engine is off. There is also a way to pre-heat (engine off) the interior. I have heard that the Sprinter's engine pre-heater doesn't heat the interior very much, but my Transit RB interior is smaller than the Sprinter, so this pre-heater might be good enough.

[trib]

Back up. The Espar D5 isn't an air heater unless there's a heat exchanger. So, the new S3 may be connected to a heat exchanger in the cabin(?) Time for me to read all the previous posts on the D5.

[Wrinkledpants]

Originally Posted by trib

Back up. The Espar D5 isn't an air heater unless there's a heat exchanger. So, the new S3 may be connected to a heat exchanger in the cabin(?) Time for me to read all the previous posts on the D5.

Negative. All the hydronic heaters will require a radiator of some type to get heat into the cabin. Or, they'll use the factory HVAC fan to blow some air in. This is usually enough air to defrost the windshield a bit, and take the edge of the interior temp of a car. But, you're not going to maintain the interior temp of a car for very long as the HVAC fan is powered from the starter battery. You're definitely not going to heat the interior of a van this way.

The Espar option on the sprinter will turn the fan on a bit, but it won't be nearly enough to heat the back of the van.

[Wrinkledpants]

Originally Posted by kcshoots

There is a MB factory option that will extend the engine hot water further back to the B pillar for use connection to an air/water heating system, it's option H88. I have ordered that option on my next van to be received in 2-3 months. I plan to use the coolant water and connect into an Espar D5 hydronic heater to heat the coolant and distribute that thru a hot water tank and heat exchanger for potable hot water before the glycol loop is returned to the engine. With some control valves I'll control the water flow to prevent it from going back to the engine when the engine is not running in order to not loose the heat to the engine block, but this hot water will be readily available as warm cooling when starting the engine. The Webasto and Espar hydronic heaters maintain water temps between 160-180F.

Inside the van the glycol hot water is passed thru fan coil(s) to transfer the heat to air to heat the living space. This system will pre-heat engine water as well as heat the van and potable hot water with or without the engine running. Cost is about half of the SMB route (no cooling) and will consume 2-4 amps at 12VDC when running, and very little diesel. Fans and pump will speed up and down as needed. All system components are below the van except for the fan coil(s) in the van. One or two are needed depending upon air desired distribution. I am using two for better temperature evenness as well as control (heat from or rear) and also with control of fan speeds and coil selection for a very quiet and efficient system that can run thru the night at low with very little noise and temperature controlled by a programmable t-stat. The heater will cycle on and off as needed, which will be little with the thermal capacity stored in the hot water tank and loop.

The factory heater options as others have said will not run below 40F without modifying the ambient temperature input of the van to the Webasto heater. This has been done fairly easily to control them to run below any desired temperature.

Either a Wabasto or Espar hydronic heater will function the same, and yes, each of these options put out 17,000 BTUs, more than enough for our vans. In comparison, the Espar D2 or Webasto 2000 diesel air heaters put out between 2,000-4,000 BTUs and those adequately heat up the van and keep it warm at freeing temps, so 17,000 BTUs is enough to heat the block, potable water and air. The block prefers to be at about 190F when running while potable hot water and hot air are best at around 100F, so there is a lot of thermal capacity in these units for this purpose. We use tempering valves so that the 180F potable tank water is controlled to the faucet(s) at about 100F, a safe and normal temp. The factory units are designed to heat the engine coolant and block very quickly at freezing or sub-freeing temps. We are just looking for comfort.

Let me know if you want more details. This system can be installed by my company or others. Happy to help.

Got confirmation from SMB that they can hook up a flat plate water heater to the H88 option. They won't do a D5 hooked into this line, though. We've ordered the van with the H88 option and the factory Espar heater. At a later date, we may add in a D5 in the way you described so we have full authority over it, and could also add in a water/air exchanger to use it as a 2nd redundant heating system.

The sprinter forum has a switch that you can wire into the front temp sensor to trick the HVAC system into thinking it's colder than 40 degrees. We'll likely use that in interim period.

Appreciate the ideas. Will definitely look you up when we're ready to pull the trigger on the D5 as it seems like you are doing exactly what we'd like to do.

[mbf_az]

Hi kcshoots,
I'm planning a Sprinter build in late 2017 or early 2018 and I've been really looking for a good heating solution. I hope to stick to diesel/electric for everything. As you and others have pointed out, I need to heat three (really four, if you include food) things in the van: water, air, and engine. After looking into a ton of options, I think what you wrote here makes the most sense. Would you please post a diagram showing how you would implement the Espar system you identified?

Some of the things that are unclear to me are:
1) How does the switch from heating the living area using heat from the engine -to- pre-heating the engine using heat from the Espar happen? Can fluid heated by the engine just run through the Espar when it is off - or do I have to put in a loop for that?
2) How do you plumb the loops for air heat, water heat, engine heat? Is one of them (say, water) always on?
3) How do you handle electricity for the air heating system? Do you use a separate switch to turn on the Espar, then thermostats to turn on fan coils? Or is the whole thing managed from a single thermostat? What fan coils should I use for a sprinter van-sized installation?
4) Where does the Espar mount under the vehicle? Should the heating tubes (carrying heat from the Espar or engine) be under the vehicle or inside?
5) How does the tempering valve get plumbed into the system?
6) You said in a subsequent post that you were ordering the factory engine block heater: would you then just make the air / water heat system completely separate from the factory engine block system?
7) And, on a related note, how are you planning to heat your food?

Thanks for any input you can give me.

[Wrinkledpants]

Originally Posted by mbf_az

Hi kcshoots,
I'm planning a Sprinter build in late 2017 or early 2018 and I've been really looking for a good heating solution. I hope to stick to diesel/electric for everything. As you and others have pointed out, I need to heat three (really four, if you include food) things in the van: water, air, and engine. After looking into a ton of options, I think what you wrote here makes the most sense. Would you please post a diagram showing how you would implement the Espar system you identified?

Check out Rixen's website as that's the system SMB uses for their $7k D5 option. I spoke with them recently and we're now reconsidering this option. Not sure how this compares to KC's setup, though. So I'll answer in regards to the rixen setup and KC can chime in with how his setup is different. I linked below the Rixen website and it has a ton of info - including wiring diagrams and layouts. Simply add a 2nd flat plate water heater into the loop to connect the engine and glycol loops. That should help illustrate how they're connected.

Some of the things that are unclear to me are:
1) How does the switch from heating the living area using heat from the engine -to- pre-heating the engine using heat from the Espar happen? Can fluid heated by the engine just run through the Espar when it is off - or do I have to put in a loop for that?
Engine and glycol loop remain separate. It's optional to connect them with a flat plate exchanger that you can see on Rixen's website. Mercedes doesn't allow any up fitters to tap into the engine coolant system without that H88 engine coolant line extension option.
2) How do you plumb the loops for air heat, water heat, engine heat? Is one of them (say, water) always on?
There are radiators with fans behind them to get air heat. it's just one continuous glycol loop with water/water radiators for hot water (flat plate), and air/water radiators with fans behind them for interior heat. To heat the motor, you add a 2nd water/water radiator with the glycol loop on one side, and engine coolant on the other.
3) How do you handle electricity for the air heating system? Do you use a separate switch to turn on the Espar, then thermostats to turn on fan coils? Or is the whole thing managed from a single thermostat? What fan coils should I use for a sprinter van-sized installation?
Rixen's setup requires a 3rd party thermostat. Use digital or the thermostat if you have an AC system hooked up. Rixen's said they're a month or two away from releasing a new control panel that has a digital thermostat built in. In essence, though, Rixen's control panel handles duties of monitoring the thermostat and aquastat - then calling the Espar to turn on.
4) Where does the Espar mount under the vehicle? Should the heating tubes (carrying heat from the Espar or engine) be under the vehicle or inside?
Mount it anywhere you have room. It's up to you whether to run the lines internally or externally. Pros and cons are what you'd expect.
5) How does the tempering valve get plumbed into the system?
Hot water from the flat plate exchanger and fresh water from tank go in one side - single temp comes out the other side.
6) You said in a subsequent post that you were ordering the factory engine block heater: would you then just make the air / water heat system completely separate from the factory engine block system?
7) And, on a related note, how are you planning to heat your food?
We're doing a microwave and induction cooktop. We'll have plenty of battery power and a big enough inverter.

Thanks for any input you can give me.

I spoke with Rixen's a few weeks ago after talking with someone that had their setup. Rixen's is who supplies SMB with their D5 hot water heating solution. It's actually fairly brilliant and design, and I think we may end up using this for our heating and hot water. It doesn't change our van order spec as we still want the engine block heater for convenience, and the fact that the remote works from a good distance to turn it on.

Sprinter and Class B & C RV System Information

A few things that sold us on Rixen's setup is the comfort hot option and connection with the engine. The comfort hot is a 110V electric element on the glycol reservoir that allows 1500 watts of heat for the glycol loop. This is enough heat that you could heat the van and get hot water down to 30-40 degrees (plugged in to shore power). There is a switch that Rixen provides to turn on this element. If the control panel senses that the 110V system isn't providing enough power to keep the van warm, you flip the furnace switch on and then it allows the Espar to power up at the same time. If it's really cold out, you'll need that D5 furnace, but the 110V will allow it to cycle off and on less. This will be nice for us since the indoor parking at the RV park has plugins, but it's not heated. The 110V option will allow us to heat the van to a temp that will keep the on-board water from freezing and the lithium batteries from getting too cold.

Because we ordered the H88 option (thanks to KC's post), that means we can connect the engine loop to the glycol loop. This allows us to use engine heat for the glycol loop and we can run the coach heat when we're driving without having to turn on the Espar unit. We want to minimize running the Espar when on the move in the event the intake or exhaust hoses get covered in snow, or to keep dust and road debris from getting sucked up into the D5 itself. We'll have a lot of windows, so the back won't stay warm in bitter cold temps without additional heating. We'd roast ourselves out if we just used the vans heater up front to try and keep the back warm.

And because you can put the air/water exchangers anywhere, we had the idea of putting a 2nd one under the driver seat, and then routing a bunch of small tubes out the side for a boot dryer. We do a lot of backcountry skiing and our boots are always soaked at the end of the day from sweat.

[kcshoots]

Originally Posted by mbf_az

Hi kcshoots,
I'm planning a Sprinter build in late 2017 or early 2018 and I've been really looking for a good heating solution. I hope to stick to diesel/electric for everything. As you and others have pointed out, I need to heat three (really four, if you include food) things in the van: water, air, and engine. After looking into a ton of options, I think what you wrote here makes the most sense. Would you please post a diagram showing how you would implement the Espar system you identified?

Some of the things that are unclear to me are:
1) How does the switch from heating the living area using heat from the engine -to- pre-heating the engine using heat from the Espar happen? Can fluid heated by the engine just run through the Espar when it is off - or do I have to put in a loop for that?
2) How do you plumb the loops for air heat, water heat, engine heat? Is one of them (say, water) always on?
3) How do you handle electricity for the air heating system? Do you use a separate switch to turn on the Espar, then thermostats to turn on fan coils? Or is the whole thing managed from a single thermostat? What fan coils should I use for a sprinter van-sized installation?
4) Where does the Espar mount under the vehicle? Should the heating tubes (carrying heat from the Espar or engine) be under the vehicle or inside?
5) How does the tempering valve get plumbed into the system?
6) You said in a subsequent post that you were ordering the factory engine block heater: would you then just make the air / water heat system completely separate from the factory engine block system?
7) And, on a related note, how are you planning to heat your food?

Thanks for any input you can give me.

Hi there. Been traveling abroad and just getting to your questions.
1) Heat from engine is dumped into IsoTemp how water tank with heat exchanger. The Espar coolant heater also heats the water in that tank. Both also indirectly heat the loop when the valves & pump for the distribution loop are open based upon water temp.
2) The coolant heater is connected into the engine coolant loop with valves that open by switch to control heat to engine. Coolant heater is turned on by switch and heats heating loop but not engine coolant unless valves are switched open. Valves are electronically controlled.
3) Heating coil(s) are activated by a switch calling for heat, which opens the valves to direct hot water to the coils. The fans are separately controlled and variable speed. Allows for nice gentle heat and quiet heat while sleeping.
4) Under the vehicle. Needs to be outside of vehicle for combustion and safety. Connections to engine are best under vehicle to reduce heat into vehicle when undesired and for safety and ease of connections.
5) Multiple ways to address this depending upon your plumbing. Best near domestic uses of hot water to maintain higher loop temp. I address at each point of use to ensure safest yet highest temperature at use and highest temp of loop.
6) I am not planning to separate the two systems for simplicity in controlling expansion, refill, connections, etc, but they are valved between them for service. I believe this provides the best value of benefits. They can be kept separate by adding another heat exchanger and expansion tank.
7) I am not heating food using water heat. I am heating food with electricity via induction stove and microwave. Heating food with water is possible but adds complexity, control, and other cons.