Hydronic and Espar Heat

Update:

I did a couple tests the last few nights to see how well the Hydronic Heat (via 110v hot water heater) will work as the temps get closer to zero degrees.

Saturday night the temps were in the 15 degree range. I set the thermostat to 60 degrees and in the morning the coach was at 60 degrees and the hot water heater was at 170 degrees (around the maximum temperature). Of course, the water pipes are all good to go as the hot water circulates thru them (under the kitchen sink the pipes are normally around 115 degrees). Also, the sewer compartment is kept at 48 degrees. So, that worked great - the system was able to keep up with the cold temps with no problem.

Sunday night the temps were in the 15 degree range also. I set the thermostat to 68 degrees and in the morning the coach was at 68 degrees but the water heater was at 115 degrees. Everything still worked great as the coach was at 68 degrees, but the system was probably running close to 100% of the time to keep the heat at that level. At 115 degrees in the water heater, that probably is very close to the minimum required to keep the heat at 68.

It will be interesting to see what outside/inside temperature is the "break even" point for the system. The hot water heater's recovery ability is the limiting factor along with the btu's required to keep the heat.

At some point, I'll re-test the Espar heating. I don't see that being a problem in any temperature. Basically, if you can heat the inside of your car/truck/van in below freezing temps (which I have 48yrs experience that says "Yes you can"), then the Espar heating will work without problems.

Update:

The outdoor temperatures have been more consistently cold over the last week or so - with some days low 30's for highs and low 20's for lows. I can tell how hard the hydronic system has to work based on how low the water heater temperature gets while it is heating. At these temps, it is not having to work hard at all. When the thermostat calls for heat, it only takes a few minutes to bring in back to the set temperature. The water heater normally stays within 10 degrees of its setting.

Our planned trip to Calgary, Alberta is now a planned trip to Florida (son decided to snowboard with friends in Vancouver instead). So, I know the hydronic heating system will work down there.

I'll post more when we get temps closer to zero - probably soon.

The last few nights it has been in the low 20's and we have the View plugged into the house. I have kept the temperature in the coach to around 68 degrees and the Water Heater Hydronic's has had no troubles keeping up. It is nice and toasty in the coach. As others have stated, the cab area really lets in the cold air unless you close that off.

I added the last step yesterday (besides additional insulation here and there) - I added a "computer" fan that blows down from under the shower into the sewer compartment. I hooked up an electronic thermostat controller that will turn on the fan if that compartment is below the set temperature. The controller will also turn on one of the solar circulating pumps to keep the pipes warm and help add heat to under the shower to be blown into that compartment. Worked fine last night.

Now we'll see how it holds up in closer to zero weather - I'm guessing all will be fine based on the system not working very hard in these low 20's temps. Also, once we get snow cover - the cold is more consistent and will test the system a bit more.

Stayed in downtown Chicago last night in the McCormick Placd parking lot. Ran the Espar in low 30 degree weather with no problems. I'm glad that I added the heat register directly on the Espar loop, because the Motoraide heat exchanger would not have kept the water hot enough.

Great place to boondock in Chicago. Right next to convention center, safe, bus to Michigan ave, etc

Testing results:

Ran the Espar last night while boondocked.

Outside temperature 35 degrees

Thermostat set at 60 degrees for sleeping

Only ran one Cozy heat exchanger, no dash fans, no water heater hydronics

Amps per hour usage according to battery monitor - 1.86 Espar 2.56 when thermostat turns on heat exchanger fans

Water heater water temperature in the morning - 137 degrees

Batteries state of charge went down 10% in 9 hours

Diesel fuel used - less then a gallon

Propane used - None

Water Heater Hydronic Heat Steps:

-- Added check value between the hot and cold water piping located under the kitchen sink.

-- Added (2) Solar DC Circulation Pump Topsflo TS5 15PV to the output of the water heater. Wired these pumps to a switch on the control wall (one/both/off).

-- Added Heat Exchanger - Cozy III - EXE-103-0EX? to under the dinette and another one in the bathroom (located in the water pump compartment). Wire the fans to switches on the control wall (high/low/off). The Cozy III Heat Exchangers are plumbed into the hot water piping of the coach. The hot water exits the water heater and goes to the dinette Cozy III and then to the bathroom Cozy III and then onto the rest of the coach's plumbing.

-- Created a smaller loop in the water piping by adding a Water Solenoid Electric Valve - 12v Dc 1/2" Normally Closed in the water pump compartment. This valve will open when the coach's thermostat calls for heat. This shortens the loop that the hot water needs to travel to get back to the hot water heater those keeping the water warmer longer.

-- Added ATWOOD MOBILE PRODUCTS 93105 Adjustable Electronic Thermostat. This allows me to set the hot water heater's temperature to 150+ degrees (my electronic thermostat controller showed 180 degrees). The greater the water temperature, the easier to heat.

-- Wired the coach's thermostat Heat Pump option to the control wall to control all the switches.

Steps to run Water Heater Hydronic Heat:


-- The Water Heater Hydronic heat can be used with Propane, Electric, and/or Espar heating the water. All 3 can be run at the same time or individually.

-- Set the electric temperature controller to 175 degrees (this will ensure that the cycles of the Atwood water heater will be controlled by the controller and not the water heater).

-- Set the coach's thermostat to Heat Pump option.

-- The Cozy III heat exchanger fans and the circulating pumps are automatically controlled by the coach's thermostat.


When the thermostat calls for heat, the circulating pump(s) will turn on and pump the water through the Cozy III heat exchangers and through all the coach's piping. The thermostat will cycle the circulating pump(s) and Cozy III's fans on and off based on the temperature.

Here is a write up for our Hydronic Heating modifications. Note that all original functions that our View came with from the factory are still in place and functional (Furnace/water heater/etc).

I really did two different modifications to produce heat - Water Heater Hydronic Heat and Espar Hydronic Heat.

I'll do the write up in two posts.

Espar Hydronic Heat Steps:

-- Completed the modification to allow the Espar heater to run without the engine being on and for an unlimited amount of time. http://sprinter-source.com/forum/showthread.php?t=668&highlight=espar+relay

-- Modified the Espar wiring to be run from the Coach's batteries. Tip: you need to modify both the "espar mod" battery connections and the fuse under the drivers seat (25 amp).

-- Added switch (Aquahot switch panel - ELE-ASM-506) to the control wall in order to control the Espar (on/off) which is also controlled by the electronic thermostat controller (will use this feature to heat the water heater in spring/fall/etc). Ran wiring back to control wall from dash to control Espar and another wire to control the dash fans (on/off - controlled by thermostat).

-- Ran Goodyear 5/8 Hi-miler heater hose from the output of the Espar (used a 1" x 1" x 3/4" pex T) under the chassis to the water heater's motor aide connections and back to the engine with the connection right below the dash heater valve (used a 1" x 1" x 3/4" pex T).

-- Installed a Cozy III (EXE-103-0EX?) heat exchanger under the pantry and ran the heater hose to this heat exchanger.

-- Tapped into the thermostat's heat pump wiring and added relay to control the switches on the control wall.

-- Added switch to the control wall to control the Cozy III (high/low/off) and to control the dash fans (on/off).


Steps to run Espar Hydronic Heat:

-- Ensure that the electronic thermostat controller is set to above 160 degrees before it will turn off. The Espar will run continuously as it takes too long to "reheat" the engine if you had the Espar turn off/on with the coach's thermostat. The Espar only uses .07 gph on low speed.

-- Turn on the Espar switch on the control wall.

-- Turn on the coach's thermostat to the Heat Pump option. The bonus with using the Heat Pump option is that if for some reason the Espar Hydronic Heat can not keep up with the demand, the thermostat will automatically turn on the LP Furnace if the thermostat's temp setting and the actual temperature is 4 degrees or more different.

-- The Cozy III heat exchanger fans will be controlled by the coach's thermostat.

-- If cold enough, turn on the Dash fans via the switch on the control wall (controlled by the coach's thermostat).

The Espar will heat the engine to 180 degrees and then it will go to a low speed or idle state. The engines electric coolant pump will circulate the coolant back to the Cozy III and the water heaters heat exchanger. The heat exchanger will produce great heat and the water heater will slowly heat up.

The Cozy III fans and the dash fans will cycle on/off via the control of the thermostat. When the thermostat calls for heat, the fans will turn on (blow through Cozy III heat exchangers) and when the coach has reached the proper temperature the fans will turn off. The Espar will continue to run and the water heater will continue to be heated via the Espar.

The Espar will slowly heat the water heater. That water is then circulated through a loop in the hot and cold water piping in the coach. There is a check valve under the kitchen sink to allow for this loop. This feature will keep the pipes from freezing. The pipes will also be protected via the cold air return that is below the shower. The Cozy III's will draw air through that vent, under shower, piping in rear of coach, and to the water pump area.

Today I installed the Cozy III heat exchanger right under the pantry door. This Cozy I plumbed into the Motor Aide connection before it goes to the water heater's "heat exchanger". This works great and will certainly take care of any heating situation that we will need. In the short testing that I did running the Espar, the Cozy goes to about 160 degrees and holds that temperature with the Cozy fans both on.

I also completed the wiring to control each of the Cozy III's high/low fans, both circulating pumps, and control of the dash heater fans. All the switches are controlled by the thermostat. So, now I'll be able to test each function as the weather gets colder. Plus depending on the temperature I can conserve battery usage by turning stuff low/off/etc.

The last piece of my project that I need to install is the Temperature Controller that will run the circulating pump if it detects that the pipe temperature in the rear of the coach is too low. This circulation happens automatically when the "water heater" hydronic heat is going but if I just run the Espar - then I need this as a backup.

I need to have some colder weather to test - once I feel confident that I'm done, I'll post some pictures and info on what I added. Don't want to mis-lead until I know it works as designed.

Update:

The weather has been a bit too warm to do any serious testing, but I have completed a few items.

---- The last time we had boondocked with the Espar running all night, the chassis battery went dead. So, I worked on moving the Espar from the starting battery to the coach batteries. That took a bit of trial and error to figure it all out but I now have the Espar running completely from the coach batteries.

---- I decided to try and shorten the circulating pump loop when the thermostat calls for heat. I found a "normally closed" solenoid valve on Amazon for $17. Now when the thermostat calls for heat, the solenoid valve opens and helps create a smaller loop. Hard to test right now because of the warmer temps, but I'm guessing this will keep the water heater water temp higher for a longer period of time.

---- I ordered another Cozy III heat exchanger. After testing the Espar and the hydronic heat from the water heater, I "somewhat" determined that the motor aide heat exchanger may not be able to keep up with heating the water as the hydronic loop cools it down to heat the coach. By adding a Cozy III heat exchanger that will be plumbed into the motor aide connection - I'm almost 100% sure that it will keep the coach warm in any temperature. The motor aide connection has shown 157 degrees on my last test. I should have that installed tomorrow.

I still have a few items to complete, but I really need some cold nights to see were I'm at. Fun project, so far.

Now I'm starting to clean up the pieces and parts and continue to test everything out. Today I worked on the noise that was coming from the water heater when I had the circulating pumps on. The solar pumps do not make any real noise but there was a buzzing sound from the water heater. After some false fixes, I found that the check valve on the cold water inlet was making the noise. I removed it (ordered new one) and that took care of the noise.

Now the system is very very quiet - just the slight sounds of the computer fans that blow thru the heat exchangers.

Really waiting for some real cold weather to do some more testing.

So far, it has turned out great. Once I get it all set, I'll post some pictures and document some of the items that I added - just in case someone is researching this in the future. All the original equipment for our 06VH is still in place and working, we just have another option.

Hopefully I'll run the Espar all night Thursday (28 degrees) to see if my changes fixed the water temps slowly getting colder thru the night.