Hydronic and Espar Heat

I've been slowly working toward the solution to be able to run our 2006 VH completely (water, showers, etc) in the winter. Here are some of the items that I have completed and items on the task list:

-- completed the mod to run the Espar heater without the engine running.

-- added hose to hookup the Motoraide feature on the water heater. This will allow us to have the water heated as we drive and also when we run the Espar Mod without the engine running.

-- wired the Espar heater to run off the "Electric Heat/Heat Pump" option on the motorhomes thermostat. This will allow the furnace to be an "online" backup to the Espar pre-heater and also allow us to set the thermostat and that will cycle the Espar on and off as needed.

Next UP:

-- ordered Aqua-hot Cozy III heat exchangers (about .5 amps). I plan to tie the heat exchangers into the hot water heater instead of using the engine heat (motoraide hoses). This way we can get heat by using propane, electric, driving (motoraide) or Espar Mod to heat the water. The only concern is the water temperature from the water heater being not hot enough, but I measured the temp at 135 degrees from the bathroom faucet with the electric switch on. These heat exchangers will also be switch from the heat pump switch on the thermostat.

-- ordered RedyHeat to keep the pipes from freezing. Will hook this unit up to the water lines in the "water compartment". This will circulate the hot water back thru the cold water lines to the hot water heater. This is temperature controlled (based on water temp) and uses very little amps.

-- already have a Honda 2000eu generator that we'll use when needed. The Honda barely sips any gas and is quieter then the onboard LP generator.

-- ordered thermostat controlled electrical 12v switch. This will allow the control of the water heater temperature based on the thermostat. The electronic switch will be wired to turn on the Propane, Electric, and/or Espar Pre-heat. I like the idea of knowing the water heater temp prior to jumping into the shower or turning on the water heater just because we don't know the temp. With the motoraide connection, we did not need the water heater on most of the time - but a few times it was a cold shower when we had used up the hot water. This will take the guessing out of it.

Today I installed an Automatic Digital Temperature Controller for the water heater(http://www.ebay.com/itm/160816907893?var=460077054980&ssPageName=STRK:MEWNX:IT). We always have the desire to know the water temp in the water heater, but even more so with the Motoraide connection.

I installed the display on the "control wall" with the other lights/switches and ran the probe (extended it) to inside the styrofoam jacket around the waterheater. I then wired the Propane waterheater switch and the Espar pre-heat mod into the control unit.

Now, we can set the waterheater temp at the desired temp and the controller will turn off the propane or Espar when it reaches that temp. The real goal with this addition was to ensure that the water temperature is set for use to heat the coach and keep the lines from freezing.

I turned on the 110v waterheat switch and the water temp maxed out at 140 degrees. I then cooled down the water in the waterheater and ran the Espar pre-heat for about 4 hours. With the Espar it maxed out at 122 degrees (outside temp in the 50's).

Now, we can heat the coach with the Espar and have it controlled with the thermostat. Plus the waterheater controller will control the Espar to keep the water heated for use in heating the coach via the heat exchangers. The waterheater heat options are Electric, Gas, or Espar with switches that allow one or all to be on at the same time.

Now waiting for the Cozy III heat exchangers to install and the RedyTemp circulating pump.

Spent good part of the day trying to adjust how the Espar mod operates based on what item is controlling it. Yesterday while testing out the water heaters control of the Espar, the water heated great but it also was 90 degrees in the coach. The way to fix this is to have the water heater only turn on the Espar and not the dash fan. But still have the fan turn on with the normal thermostat. Also, I'd like to turn in the Espar heater from the dash manually.

So, ran more wires, used a few relay's, and tried many different ideas. I believe I have it all working, but need one more relay to complete the job. That way the water could be heated with the Espar in the summer without heating the coach.

Slowly getting closer - soon the outside temps will gives me a good test.

Today I finished up the wiring and added a new switch panel from Aquahot that has 3 switches Gas, Electric, and Engine.

I used the battery monitor to see how many amps the Espar used. Without the dash fans on, the amp draw was 1.5amps. With the dash fans it was 8.5amps. That is a bit of a problem - 7amps for the dash fans seem high. I'm hoping that I can just not run the dash fans and instead install 2 (.5 amp each) Cozy III heat exchangers to heat the coach. I'll find out soon when I receive the Cozy III's.

I also decided against the Redytemp recirculating pump. First the price is quite high at $400, plus it is 110v and would require that we always have the inverter on. Just dont want to take the chance that someone clicks off the inverter. So, instead I ordered a 12v solar recirculation pump that uses less then 5watts. Also ordered a recirculating valve to handle the water circulating.

Getting closer.

Today I installed the first Aquahot heat exchanger. I installed this one in the bathroom. The unit sits in the space where the water pump is located and comes out into the bathroom on the floor below the closet door. I don't have the circulating pump hooked up yet, but just for a test I ran the hot water out the bathroom faucet for about 30 seconds or so and connected the fans on the unit to a battery. Just in that short time, the heater was putting out quite a bit of heat and was very quite (almost not noticeable).

Now waiting on the circulating pump.

Update:

After a few days trying different ideas and testing out our hydronic heating solution, I think I have it going in the right direction. When I first installed the 2gpm 5watt solar circulating, the pump would not keep the heat register hot enough. I then ordered a 3gpm 15watt solar circulating pump and this worked. Now the heat loss from the beginning of the loop to the end is under 8 degrees without the heat register fans on and 12 degrees with the fans on. This works.

I then installed a second heat register under the rear dinette seat. Now with both registers on and the circulating pump on, I'm getting consistent hot heat from both registers when I'm heating the hot water via shore power. Now, I need to do some testing to see how it works in much colder weather and with the Espar heating the water. Now that I have it functioning, I can do the testing.

Next, I'll wire everything into the coach thermostat and switches to control the pieces and parts.

Today I wired everything together and let the thermostat control the hydronic heating. So far, it is working great. It is quick to heat the coach and is fairly quiet. I checked the amp hours usage on our monitor and it was 1.9amp hrs with everything running- very pleased with that. Right now it is in the 50's and when the hydronic heat turns on, it heats up quickly and it takes some time for the thermostat to demand heat again. Might have something to do with the residual heat in the registers.

Right now I'm running on shore power with the water heater on 110v. I have it setup so that I can run off 110v, gas, and/or Espar. This weekend we are to have temps below freezing, so that will help out my testing. I'm anxious to try running it off the Espar alone.

Next I plan to add a small register in the outside water compartment. With the setup, the hot water circulates thru the cold water pipes keeping everything warm. I'm hoping this will also provide heat for the drains.

Last night I ran the hydronic heat using the 110v electricity to heat the hot
water heater. I set the thermostat to 69 degrees with the night temperature
going down to 36 degrees.

I checked this morning and the coach temp was 69 degrees. The only issue that I
could see is that the water heater temperature was down to around 118 degrees
when it is normally 140 degrees. This was concerning, thinking that the
hydronic heating loop was cooling the water faster then the water heater could
catch up.

Well, after doing some research I found that the Atwood water heaters are set to
max temp of 140 degrees then will cycle down to 115 degrees before heating the
110v element again. This was a relief finding this info. I ordered an
adjustable temperature thermostat for the Atwood water heater - this hopefully
will cycle more often.

Tonight I'm running the Espar engine pre heater only (no 110v or no LP). The
overnight temperature will be around 30 degrees. It is around 40 degrees right
now and there is little doubt that the Espar will take care of the heat as it
cycles on for just a few minutes and heats it up to 70 degrees without effort.
I have the dash fans controlled by the thermostat along with the hydronic
heating.

Because the hydronic heating uses the hot and cold water pipes as the loop, all
the water pipes are warm and will not freeze.

Getting closer to having it ready for our Calgary trip over Xmas.

Last night we slept in the motorhome with the Espar/Hydronic heating the coach. The outside temps were 35 degrees. I have a switch for the Espar that will run the Espar but the dash fans only come on via the thermostat. When the thermostat would call for heat, the dash fans along with the hydronic heaters would turn on. Within probably a minute or so, the coach would be at temperature and the thermostat would turn off the dash fans and hydronic system.

I have great confidence that the Espar heat will provide all the heat we will need even when temps are close to zero.

The part I didn't like was the fact that the motoraide connection only heated the water heater to 95 degrees. While this will work in keeping the pipes from freezing, I would expect to get more heat from the engine. Today I'm going to try and install a second solar water pump (5watts) right before the water heater in the motoraide Hose. We'll see if this helps. Also, I need to review my motoraide hose routing.

Espar was great last night, giving me the confidence that it'll handle the real cold.

Tonight will be a good test, low of 20 degrees as we boondock at a casino parking lot in Wisconsin Dells. We'll run on the Espar the entire night.

Noticed on the way up here (about a hour drive), that the motoraide heated the water heater to 135 degrees. But while sitting with just the Espar on, the water heater temp goes down. I'm guessing I need another circulating pump to get more of that heat to the water heater.

Trail and error, but making progress. At least I have a full propane tank and a good working furnace if needed.