We get this question often and the answer is usually one of THREE possible answers:
1. You are losing heat underground because you have low-quality pipe (NOT purchased from OutdoorBoiler.com of course!)
2. You recently installed your insulated PEX pipe (this is NOT lost heat from your PEX underground water line, but rather heat escaping from the earth via the path of least resistance - the earth you disturbed while trenching. This will go away after the ground settles.)
3. You are losing heat underground because you have a LEAK in your outer casing. Water fills the outer casing, sucks heat away from your PEX tubing, and that heat gets absorbed by the earth - and the earth can absorb an infinite amount of heat!
Often, people install new underground insulated PEX, and during their first winter, the snow melts between their house and outdoor wood furnace. And they think they have a problem!
Do not worry! The solution is to measure if you are losing any heat underground with a simple test - we call this the "Delta-T Test". See the instructions below to complete this simple test, and you will likely have peace of mind knowing that you are not wasting fuel.
In summary, here are the possible causes, and the recommended solutions:
Reason Snow is Melting
1.) You may be losing heat underground because you have low-quality pipe
Low-quality components will not provide the insulation value you need to prevent heat loss.
2.) You recently installed your underground pipe
This is NOT lost heat from your underground pipe, but rather heat escaping from the earth via the path of least resistance - the earth you disturbed while trenching.
This will go away after the ground settles. You can do the Delta-T Test just to be sure.
3.) You are losing heat underground because you have a LEAK in your outer casing
Water fills the outer casing, sucks heat away from your PEX tubing, and that heat gets absorbed by the earth - and the earth can absorb an infinite amount of heat!
Here is the Delta-T test procedure that can be used to see if you are wasting wood by losing heat underground:
Wondering: Am I Wasting Money? Am I Losing Heat Underground?
Try This Simple Test...
You can check your insulated PEX pipe for heat loss in about 5 minutes. This is called a “Delta-T” test which is simply a measurement of how much heat is lost through your PEX pipes underground into the earth, or the air. The instructions for the Delta-T test are as follows:
- MAKE SURE ALL LOAD IS TURNED OFF. All unit heaters and outdoor wood stoves must be disabled, and no hot water faucets can be open during the test. Make sure nobody is taking a shower, and your furnace blower fan is off, otherwise, the test results are useless.
- Using a digital thermometer, take temp readings at the back of your outdoor wood furnace on BOTH the Feed Line and Return Line.
- When taking readings, apply temp sensor, cover with insulation, and secure in place with Velcro or tie strap. Make sure the sensor is touching a metal surface. Leave attached at least 90 seconds or until temp stops rising on the readout display, whichever is later.
- For FEED LINE, apply temp sensor to fitting or pipe close to furnace back wall. We want the true furnace water jacket temp, before any heat loss from the pipe.
- For RETURN LINE, apply temp sensor to fitting or pipe at least 4 inches from your outdoor wood burner body. We want the temp coming back from the line before it mixes with the water in the water jacket.
- Do NOT use an infrared thermometer on PEX or PAP tubing. It will not give an accurate reading. An Infrared thermometer can only get accurate readings on metal fittings or pipes.
- Record these readings. If you see temp differences larger than one degree per 100 feet of underground PEX pipe, you are experiencing larger heat loss than is acceptable.
If your heat loss is TOO HIGH, you should consider replacing your PEX underground. Be sure to only use Heat Mizer brand PEX insulation from OutdoorBoiler.com so you can maximize your savings for decades.
Contact OutdoorBoiler.com for more information and to browse more outdoor wood boiler parts M-F from 9 am-8 pm at (231) 861-8200.