This unit has been operational for about 6 years and suddenly quit, not even operational on TEST. There is a 25 v current at the power terminals and the resistance on the Auto-Trac wires is at ~31,500 ohms @ 33 degree outside temp. Voltage at the connectors leading to the unit itself are negligible (~1.3V) whether the switch is off or on Test and the unit is plugged in! The switch always gave a click when it engaged before, but there is no indication of such now. My suspicion is that the humidistat itself is defective, but I'd like to know if there are some additional tests to check that out.
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A simple check you can perform on your aprilaire 760 is the following:
1) locate the two brown wires coming out of the 760 (these wires will be wired to tell the 760 to turn on when the hvac bower is on and the humidistat is calling for moisture).
2) temprarily disconnect the two brown wires from the external wiring and then short the wires together. All you're doing here is bypassing the your thermostat and bower-on indicator.
With the 70 unit plugged in to the wall outlet and the two brown wires connected together, both the fan and the solenoid valve (water inlet valve) should both be activated.
you need to make sure your humidity level in the house isnt higher then what your humidifier will provide at any givin outdoor temp. this chart is in the owners manual. you cant remove the wires going to the ODS or it will give an error unless you have a resistor to put in its place. Anyway if the humidifier works in test mode according to AA it works so you may have higher humidity than you think, the highest your gonna get is 45% as the temp outside drops it will allow less humidity so it doesnt cause window condinsation (property damage) here is a copy of the chart. the #s on the left are the dial setting
TABLE 2 – % Relative Humidity Guide
Outdoor Temperature (°F)
-10°F 0°F 10°F 20°F 30°F 40°F
1 10% 10% 10% 15% 20% 25%
2 10% 10% 15% 20% 25% 30%
3 10% 15% 20% 25% 30% 35%
4 15% 20% 25% 30% 35% 40%
5 20% 25% 30% 35% 40% 45%
6 25% 30% 35% 40% 45% 45%
7 30% 35% 40% 45% 45% 45%
The tune up kit that I ordered arrived on Friday and I installed most of it on Friday night. While it is nice to have a new frame and the distribution panel and I think the price of the whole kit was fair considering it comes with the parts and 2 water panels, the fix was really simple.
The kit came with the water distribution tube with with a new blue orifice (Aprilaire #4232) already inserted. This orifice is in the end of the plastic tube at the solenoid end. When I removed the old water distribution tube, the old orifice was not really dark blue anymore but kind of a light blue and was deteriorating from 12 years of exposure to the chemicals in the water. What should have been a pin-hole size opening in the orifice was up to about 2mm or a little more so the orifice was letting way too much water through.
If anyone else has this leaking problem, and your orifice is several years old, I would check that first. It is a $2.75 part and may be the cause of the leak. The whole feed tube kit is only $8.75 and includes the feed tube, nozzle, orifice, ferule, compression nut, strainer so if you need to replace the orifice, I would order the whole feed tube kit for a little bit more.
the 760 send power out the humidistat is just a switch if you touch the two brown wire coming outof the 760 the humidifier should come on if it doesnt and you had appiled power to those wire you probably shorted the 760 control board
It could be that the humidistat is not calling for humidity. Make sure that you have the dial turned up all the way (as far as it will go, just to test it) and that the blower on the furnace is running - if the unit is properly wired, the water will not run unless the blower on the furnace is running. This should do the trick. If not, the only other thing would be a bad humidistat. Good Luck!
I had this problem several years ago. In order for the water to flow, the outside temperature sending unit must indicate to the controller that it is less than 60F. If not, the unit will not operate outside of test mode. Check the temp outside where your sending unit is (could the sun be heating that side of the house?) and ensure that the circuit to the sending unit is working. I had a bad wire splice inside a wire nut stopping the circuit. Took me a long while to figure it out.
If the outside temp and your sending unit circuit is ok, I wish you luck on your troubleshooting.
Turn the control knob to the test/reset position untill the change water panel light blinks to reset the change panel timer. Make shure the furnace is running calling for heat.Turn control knob to prior setting after resetting timer. Hope this helps.