A Question for the Data Guys ...

FJL

Is there a program or device that will measure how often my steam boiler fires and for how long?  I could put a timer on it, but Id like to know more than just for how long it has fired within a certain time period.  I'd like to know when during the day and for how long each time.  Is there anything that will measure and record that information?

Mike Kusiak_2

Datalogger

Take a look at the last posting in this thread:



http://www.heatinghelp.com/forum-thread/133219/Replacement-for-a-Smith-Mills-2000L



I am using the Lascar thermocouple datalogger, which allows you to record temperature readings in intervals from every 10 seconds to several minutes. In my graphs I am sampling every 30 seconds, which allows me to record continuously for 11 days.



Thermocouple probe is located at the flue pipe of the boiler.



Here is the link to the unit I am using:



http://www.testequipmentdepot.com/lascar/dataloggers/elusbtc.htm



This is the same logger that JPF321 is using to generate his data ( I got the info and recommendation on it from him)

FJL

Datalogger

Yes, I saw that thread.  I hadn't thought of using that device, but I suppose that would do it.  I'll have to familiarize myself with that device.  I could just point it at the burner, correct?  Right now, that is the only info I'm seeking -- how often the burner turns on and off.  Would there be a way to do that?  

Mike Kusiak_2

Boiler cycling

By looking at the graph, you can see exactly when the burner fires and shuts off. Just note the time when the temperature falls and subtract it from when it first rises. That is the time interval that the burner runs. You can also generate a printout of the data which lists each time interval and the temperature at that given time. Add all the firing intervals and you have the total elapsed firing time. You can zoom in on the graphs to expand each firing interval for better resolution.



You have to do more than simply point the logger at the burner. The probe must be physically mounted on the flue where it can sense the change in temperature when the burner fires.

FJL

OK ...

I guess that is the way to go.  My only concern was whether there was a lag time between when the burners ignites and the flue gets hot, but I guess there isn't much?  I'll give them a call.  I have a few questions about exactly how its done.  What gets attached to what.  

Mike Kusiak_2

Response time

There is a slight time delay between the start of firing and sensing heat at the flue, but it is negligible compared to normal firing times. Also, there is a delay in temp drop when shutting down, so the error effectively cancels out if figuring the elapsed time.



To get the best response time I try to find a small hole in the flue pipe to insert the probe directly. You can always drill a 1/8" hole in the flue pipe for the probe and then when done with measurements, put a self tapping screw in to close it up until next time. You can also strap the probe to the outside of the pipe, but the response time will be longer.



Here's the setup.You mount the probe on the flue pipe, then plug the probe into the datalogger after setting up the measurement parameters with your computer. After the desired measurement time, unplug the logger from the probe, connect to your computer and read the data. Thats all there is to it.

FJL

The Set Up

Thanks.  So the datalogger stays attached to the probe.  The datalogger won't get damaged being close to a heat source?



You said look for a hole in the flue pipe.  I assumed it had no holes.  Aren't the gases supposed to say in the pipe?  I am leery of drilling holes into the flue pipe.  Or am I being skittish?

Mike Kusiak_2

Probe

The probe has a cable about 4 feet long, so you can move the logger far from the boiler.



If a combustion test has ever been done on your boiler, there will already be a hole (hopefully plugged)  somewhere close to the boiler outlet to insert the tester probe. The probe is less than 1/8 inch in diameter, so it can be poked into most any opening. If it makes you nervous, just strap it on to the outside of the pipe close to the boiler with some bare wire.



Make sure the boiler is shut off before you do anything on or near the flue pipe as it can reach several hundred degrees while firing!

FJL

Got It

If the probe is smaller than the hole, I assume I should cover the hole with something?  Duct tape?  The boiler is only a few years old, so if a combustion test was done, it would have to have been done by the contractor who installed the boiler.  I don't know if that is a standard test or not.

Mike Kusiak_2

Flue pipe

Don't put anything that can burn in, on, or around the hole or flue, as the temperatures involved could melt or ignite it. Aluminum foil would probably be ok.



If you look at the photos in the Smith post showing the Hartford loop, you can see the logger hanging by the probe wire, near the floor.

FJL

Flue Pipe

Am I just being overly concerned?  Is a partial opening in the flue, where the probe enters, no big deal?  I have been assuming that the flue should be air tight sealed. 



I'll check out that photo in that thread.



Thanks again.

Mike Kusiak_2

Negative Pressure

A natural draft boiler should have negative pressure (slight vacuum) in the flue at all times, so the joints and other openings are not tightly sealed and will not leak. Only if there was positive pressure in the flue would there be any chance of leakage, and if there was you would have far greater problems than the leakage from a 1/4 inch hole.



A forced draft or condensing boiler will have a flue under positive pressure and must have tightly sealed joints and no unsealed holes.