Lockout, Low Fan Speed
Lochinvar WBN050 I installed in 2008 has recently begun to lockout and throw the low fan speed message. Once in September and twice in the last ten days. It has always occurred during the 100% fire rate while in DHW. Reset puts the boiler back online with no issue.
The first time it did this in September I went ahead and performed the annual service expecting possibly that foreign object might have made it to the fan and momentarily slowed the fan. No sign, however, of anything at all. All wiring and connectors inspected for any issues. Close inspection of the fan itself revealed nothing unusual.
About ten days ago after the second lockout I disassembled again this time inspecting the circuit boards. Both main board and fan board are in pristine condition.
Watching the fan speed during both space heating and DHW I find the fan speed rpm to always be perfectly steady and at the exact speed one would expect, 500 rpm/ 10% of fire rate. No blips.
I suspect that the fan may not actually be slowing at all. The boiler may be sensing a false indication of a 30% or more reduction in speed.
The boiler has performed flawlessly these past seventeen years. only shutting down three times due to intake blockage as it should have. Twice a leaf, one time a small paper wasp nest.
Any thoughts as to my next move?
Comments
-
-
-
how dirty is the squirrel gage blade?
0 -
The hall sensor in the motor could possible be failing or more likely your bearings in the motor are failing and when they get hot they are creating to much friction and slowing the fan speed down. The hall sensor will pick up the reduction in RPM and report to the control that it is below its programmed speed and shut the system down.
0 -
The squirrel cage has a very light dusting. Very little dust. No end play. No side play. Spins freely.
I'll try the fan lead disconnection and see what results.
0 -
If I unplug the four wire fan lead while the boiler is running in space heating mode and fan speeds up, is the boiler actually defaulting to 100% fire rate?
0 -
Categories
- All Categories
- 86.2K THE MAIN WALL
- 3.1K A-C, Heat Pumps & Refrigeration
- 53 Biomass
- 422 Carbon Monoxide Awareness
- 90 Chimneys & Flues
- 2K Domestic Hot Water
- 5.4K Gas Heating
- 99 Geothermal
- 156 Indoor-Air Quality
- 3.4K Oil Heating
- 63 Pipe Deterioration
- 915 Plumbing
- 6K Radiant Heating
- 381 Solar
- 14.9K Strictly Steam
- 3.3K Thermostats and Controls
- 53 Water Quality
- 41 Industry Classes
- 47 Job Opportunities
- 17 Recall Announcements