The advantages of having a wood furnace a clear: instead of having to pay thousands in heating bills annually and polluting the environment, it is better to burn the wood that grows in your backyard and get all the heat you need for free or almost free.
The matter of purchasing and setting up this kind of equipment has been a subject for discussion for a while, and now, it is time to talk about the parts that go along with it.
A circulator pump is a device that will constantly recirculate the hot water between the boiler and the house, thus assuring a timely and constant delivery of heat.
It is crucial to size the circulator pump properly, as it will directly impact the performance of the heating system.
First, the circulator pump's flow rate in Gallons per Minute (GPM) has to be determined, based on the required BTU load.
A typical wood boiler operates at a 20F temperature differential (difference between supply and return temperatures) and the house it heats would normally require 1 GPM per every 10,000 BTU's.
At 180,000 BTU load, the flow rate would be 180,000 / 10,000 = 18 GPM.
Next step is to calculate the pressure drop in head of ft, which is associated with PEX tubing runs from the boiler to the house and back.
In this example, we will assume that the wood stove is installed 50ft away from the residence.
By using a pressure drop table, supplied by the PEX tubing manufacturer, we can locate the pressure drop in PSI or ft of head for a selected PEX tubing size at a given flow rate.
For 1' PEX tubing, pressure drop for 100ft of tubing at 18 GPM would be 36 ft of head.
All that's left to do, it to match the data we have (18 GPM, 36 ft head) with the pump curve chart, supplied by the manufacturer.
If using a Taco circulator pump, the correct model would be a 0011 or a 0013 model.