The purpose of using the nimbus control is so the ideal flow rate can be achievable for any circulator in your system. Flow rate is important. A boiler circulator running too slowly can overheat, whereas running too quickly can negatively affect stratification in thermal storage tanks by stirring the hot and cold water.

Using the manual dip switch settings on the nimbus, you can test different speeds in order to determine the best flow rate for transferring heat.

The default settings are with all switches in the off position as seen here.

Using the dip switches, you can manually set the controller to a fixed speed. You are able to configure it in one percent increments between 27 and 100 percent output. Please note, we have found most circulators to be unable to work below 40 percent as set on the nimbus control.

Using the Nimbus controller in this manner will give you a single user defined speed for most any circulator. Our personal experience is with using the TACO circulators, 007, 0010, 0014 models.

Using Nimbus for True Variable Speed with NFCS

Another way to use the nimbus is in conjunction with a nofossil control system, NFCS, which I have installed at my own home, which can be seen live, here.   The analog out(AO), on the left hand column are the four outputs being controlled with 4-20ma control signal.

The benefit of using the Nimbus with the NFCS is to drive your circulator speeds dynamically based on current heating system temperatures and rule sets. This allows you to have even greater control over your heating system and also run your system at its optimum settings.

In this setup, the output of the Nimbus control is being controlled by the NFCS via a 4-20ma signal. The NFCS connects directly to each specific nimbus controller with a signal wire coming through a variable speed breakout box.

One of the first things you need to do when setting up your variable speed controller to work with NFCS is to configure the jumper so it will work with 4-20ma signal.

Using the manual we can determine how to best set the Nimbus for our system.   This is an example of a configuration, set to run on current control. This example is also to run at 60 percent if no signal is present. Where the manual refers to a “fan”, this applies to the circulator in our scenario.

A. Fan On / Fan Off Feature (switch #1): To turn fan(s) off below the set idle speed (see table 3). Set switch #1 to the ON position. To keep fans running at idle speed below the set idle speed, set switch #1 to the OFF position.

B.

C. Control Signal Loss Options (switch#6): If the control signal is lost, (less than 4mA in I mode, less than 2VDC in V mode) when switch 6 is OFF fans will continue to idle or remain off. To send fans to full speed if the control signal is lost, set switch 6 to the ON position.

D.

In the event that the NFCS is offline and not supplying 4-20ma signals, the nimbus can be configured so that it can either run in one of four preselected idle speeds or simply run wide open assuming that the aquastat or other control switch is supplying line voltage to the nimbus.

Connecting a variable speed control unit to the NFCS

For this model you are supposed to have .096 inches of H20 water column.   It was a bit hard to get draft started at first as it was about the same temp inside as out at 75 deg F. I started a wad of cardboard near boiler tubes then surprisingly though it took off without too much effort.  After a few minutes there was .07 ” of water column and that held steady thru the burn till the wood was burned out.  My guess is that during the winter the draft won’t be an issue because of the temperature difference in my flue and outside. I plan to run it in the summer for domestic water every few days and will hook up a draft inducer for starting or for times when draft is bad. I’m at the bottom side of a hill and draft  isn’t always so good.

The first fire was small just to get the ceramics warmed up.  Still have some connections to be made till the system is all finished. The boiler is directly connected to an insulated vertical 250 gallon tank which had been a propane tank and can thermal siphon. The system is also connected to another 500 gal. tank in the residence. After all connections are made I’ll get more pictures of the install.

This unit will be tested for UL and CSA within a month.

Here’s a video of my first fire about after hour into the burn.  Check it out.

We had a great time at the show and talked to hundreds of people. Our Varmebaronen boilers caught the attention of crowds of show goers at various times. We had a sign saying “Look through the Peep Hole at the Fire”. That sign certainly produced interest and curiosity in people of all ages.

After checking out our live boiler, many people were impressed with the flames we were producing in our Vedolux 30 wood gasification boiler. However, even more were amazed at the fact that we were burning wood with NO visible smoke.

Ultimately the show was a good time, we had fun talking about our wood gasification boilers and accumulation tanks.

Here is a video clip and some photos from the show:

Varmebaronen Traveling Boiler System

Talking boilers

Tent and Boiler Display

Varmebaronen Boilers

Checking out the boilers

See the Fire

These units were built with an insulated stainless frame and roof to house the boiler.  Inside the steel housing, the unit has a 100 gallon tank and circulating pump.  The boiler was designed to be a “plug and play” installation.  All you needed to do was connect the electric and plumbing on the two ports coming out of the 100 gallon tank.

When I first purchased the EKO 60, I used it outdoors for a cold season until I was able to build my barn.   I have installed a 500 gallon storage tank in my basement.  The tank is a used propane tank which was professionally inspected, cleaned and modified to add the plumbing ports. 

This summer I built my barn and replaced the 100 gallon tank that came with the boiler with a 250 gallon insulated tank placed just outside the boiler housing.  The 250 gallon tank is a used propane tank as well.  I had a base ring installed on one of the rounded ends; I did that so I could stand it up and save floor space.

When building the barn last summer, I left an opening the size of the face of the steel boiler housing.  I pulled the boiler flush with the outside wall and installed flashing to seal/connect it to the wood siding.  Having the boiler facing the outside is very convenient; I can load wood without worrying about smoke issues etc.  I can treat it more like I did my outdoor wood boiler with the exception of the dry wood needed for the gassifyer.

A couple of these photos show what it looks like inside the barn.  The one photo shows the boiler enclosure with the insulated removable side panels off.  There are removable panels on the opposite side as well.  The back side of the boiler has doors on it similarly to the front doors.

There is a draft meter mounted on the side wall of the boiler.  I have been experimenting with different draft control as I had lots of trouble with too much draft.  I’ve learned that without the draft meter (Dwyer Mark II), I wouldn’t have known what was going on in relation to my burn variation.  It has helped me to configure my boiler’s air mixtures to achieve great burns.

Ingredients:
-6 lb chicken
-Some salt and pepper
-Rotisserie chicken seasoning
-Olive oil
-One happy sous chef

Instructions:
1.  Spread olive oil on the chicken and sprinkle your seasonings on.
2.  Stuff the chicken with ice cubes to make the meat very moist.
3.  Wrap the chicken in seven layers of aluminum foil
4.  Wrap your chicken with wire and leave a long enough piece extending from the bird to act as a handle.  This will help you to take the chicken out of the fire box.
5.  Wait until the fire is at the end of its cycle and there are just a few inches of red hot coals left.
6.  Put the chicken in the coals and let it sit until it’s done.  I cooked mine for an hour and a half.  If you open your bird and it isn’t done, throw it back in for a while longer.
7.  Set the boiler temperature so the fans won’t continue to blow on the fire.

Note: After an hour I peeked in and the coals looked a bit black, so I flipped the chicken and turned the fans back to normal so the fans would run again.  After another half and hour I went and pulled the chicken from the fire box.

Hot water storage tank before it was insulated

Efficiency:
A properly sized hot water storage tank can lessen your wood usage. The average American house uses about 82 Million Btu’s annually. Assuming the boiler system is 85% efficient, 82 Million Btu’s translates into 4 – 5.25 hardwood cords or 6.5 to 11.75 softwood cords.

The increased efficiency is due to the fact that the boiler is designed to operate best when burning at full pace. The hot water tank stores heat for later, and allows the boiler to continue to burn for a longer period of time at maximum output. Once the demand is finally met, the boiler will idle.

Convenience:
Because the heat is stored in the tank, the heat is retained long after the wood or coal is depleted (the length of time is variable based on demand and on the volume of water in the tank). This means that you don’t have to reload your boiler until your tank temperature drops to an unusable temperature (the unusable temperature varies based on your heating system. Typical unusable temperatures are below 140 degrees for baseboard and below 110 for radiant floor).

Starting the fire once every few days is sufficient during warmer months in fall and spring or in the summer when using the boiler only for domestic hot water. So ultimately, even though the boiler will produce heat without the additional storage tank, the added efficiency and convenience exceeds the initial investment of a tank.

Creosote:
When you size your boiler, typically you are trying to size it for the coldest temperature your area sees in the winter. Our area is 0 degrees. We may see 0 degrees for a week or two out of the year, so that means that 90% of the time our boiler is “over sized”. This means that in the spring and autumn months the boiler will tend to idle more if no storage tank is used.

When the boiler is idling, you have the potential to build up creosote in your primary chamber and chimney. If a hot water storage tank is in use, it allows the boiler to burn at full capacity for a longer period of time when first lit. This allows the tar and creosote causing agents to be burned off during the gasification. If system demand is met near the end of the burn, the fuel left is in a charcoal state.  If the boiler idles at this point, it will not cause any creosote.