Washington State Vedolux 350 wood boiler

The following story is an installation submitted to us from a customer in Washington State.

I decided to pull the trigger January 2019 and install a Vedolux 350. I live in Washington state and the state’s Department of Ecology has very strict standards for wood burning hydronic appliances. The Vedolux 350 and 450 were the only products approved for indoor use and also require a closed heating system (the water in the boiler is not open to the atmosphere like outdoor wood boilers, none of which are approved for installation in WA). This means I can connect it directly to my existing hot water radiant system and put the propane boiler in standby when using the 350. 

The 350’s heating capacity with a 500 gallon storage tank is a good match for my home. I contacted my local propane company to see if they had any decommissioned tanks I could use for a storage tank. They had one 500 gallon tank they would sell for $200. I then had them add 3 additional ports for pipe connections where I needed them. 

I had the 350 delivered to the propane company since they had the ability to unload the 1,400 pound pallet from the freight truck and load it into my trailer. Then came the process of getting it off the trailer into the garage. With the neighbor’s help it slid off the trailer and into the desired location at the back of the garage.

After seeing the tank I would use for storage I realized two things. I would need to be able to move the 1,000 pound tank around the garage during construction. I also needed to permanently elevate the tank so I could easily access the pipe connections on the bottom. So, I built two large dollies with casters rated for the weight of the tank when full of water, 5,200 pounds. The casters also have retractable feet I can drop down for permanent placement in the final location.

Another consideration arises when installing wood burning appliances. National fire codes prohibit installation in garages. My project had to included erecting a fire-rated wall to create a mechanical room separated from the garage space. My oversized garage had exactly the right amount of space for this.

In addition, my home owners insurance company was very reluctant to continue insuring with any wood burning appliances in the home. I then had to take time to go insurance shopping. It didn’t take long to find an alternative who had no problem with wood stoves/furnaces/boilers. The only stipulation was is couldn’t be the primary heat source.

I was reminded again why I don’t to drywall for a living.
The makeup air vent is installed.

The storage tank is placed in it’s final location and connected to the 350, expansion tanks, and the circulating pumps. Now awaiting the arrival of tank insulation.

There are two circulating pumps. One is a variable-speed pump (right) to move hot water to the radiant heating system. The other single-speed pump moves hot water through a brazed plate heat exchanger to preheat cold water entering the water heater for the domestic hot water, faucets and showers.

Brazed plate heat exchanger for domestic hot water preheat.

I needed an automated way to put the propane boiler for the radiant system into standby if the water temperature in the storage tank was sufficient to fulfill the radiant heating requirement. And then switch back to the propane boiler when the hot water is depleted. In the end I decided to use two Heat Timer modulating controllers.

The right-hand control uses an outdoor sensor to determine the required radiant water temperature based on the outside temperature. A second sensor in the storage tank is used to decide if the water temperature is sufficiently hot. If yes, then the propane boiler is put into standby and the left-hand controller is enabled allowing it to activate the variable-speed pump and mix hot water from the storage tank with the radiant system water. A temperature sensor in the radiant system is used to vary the pump speed so that the desired target water temperature for heating is maintained. First full load test. The Vdolux 350 works flawlessly and is easy to light. I’m burning a mix of Ponderosa Pine and Douglas Fir with a moisture content of 8 to 14 percent. The next several weeks were spent looking for and fixing plumbing leaks.

Tank insulation finally arrives.

My winter wood supply. In my area there’s and infinite supply of wood available from the neighboring property owners who are happy to have me come in and thin and clean up dead/dying trees and keep the wood. Before this project I used to have to sell 10 cords of wood per year to pay for my propane. Now I can heat with the Vedolux 350 for a year with 4 cords and sell the other 6 and pocket the cash.