Vitodens Operation

Mike T., Swampeast MO

[Outside temp has some serious read gaps in this period. It's always been terribly finicky getting the computer interface into just the right position to pick up all the wireless sensors.]

The continued low delta-t had me a bit confused. Gas consumed (about 12 ccf) agrees <I>very</I> closely with expected loss during the period. Measured supply temperature is somewhat lower than the "target" but that was expected.

Finally had the time this morning to observe the boiler directly. The "boiler temperature" it reports is utterly nailed at 120°. The "target temperature" it reports is about 1° higher than the supply temperature I measure.

The "missing" delta-t appears to be in the boiler itself! Boiler temperature of 120° minus measured (and essentially rock-steady) return temp of 94° = 36° delta-t across the system as a whole--pretty damned close to my 37° prediction during maintenance.

jerry scharf_2

how is your supply temperature sensor attached

Mike,

One problem that can occur is with the attachment of the temperature sensor to the supply pipe. What I like to do is put some thermal conducting paste under the sensor, then put the pipe and sensor under a 2-3 foot sleeve of pipe insulation. This allows the sensor to read much closer to internal water temperature. What's the diameter of the pipe you are attaching the probe?

jerry

Mike T., Swampeast MO

Pipe is 1" black iron. No conductive paste but they're well insulated with no airflow against the sensing element. With constant circulation and around 20 hours of continual firing, I'd imagine that the supply temp I measure is pretty close to the actual at that point in the system. Believe I have some of that paste lying around. Will see if it makes much difference.