My desert springs humidifier doesn't work. I suspect that it's about 6 or 7 years old. The furnace is still running and I've tried all solutions that seem obvious to me. Is it possible that the motor has burned out? How can I tell. thanks

If the humidifier has a 6" duct on one side, this must be open in winter you should find a handle, if there is not any label, move it so the handle is parallel to the ductwork.
If the humidifier do not have a duct on one side, it must have a fan, if you can't hear it working, probably is time to get a new humidifier, and make sure contractor check furnace heat exchanger for CO2 leaks.

http://www.desertspringproducts.com/desertspring/products.asp

Hope this helps, check and see if humidistat is set to 35% humidity and that bypass damper on humidifier is in the open position or winter position.(humidistat is usually located on cold air return duct near furnace). Next, replace humidifier media pad, remember to replace media pad (filter) annually, you also may want to clean any lime deposit out of humidifier housing with a solution of warm water and white vinegar before installing your new media filter.Remember to turn power off at side of furnace when cleaning humidifier and replacing media. Before installing new media turn power back on to furnace, set humidistat to the on position, turn furnace thermostat above room temp., and inspect humidifier to see if water is running from top,(you may want to have a bucket under humidifier when checking for water), if you see water running, turn power back off to furnace, properly install new media filter, reconnect humidifier cover & set humidistat to 35%. If you do not see water present, check water supply valve to humidifier and make sure its turned on. If water supply valve is open, then check water supply tubing for blockage.And the last things to check is to make sure all registers through out your home are open and not blocked by any objects, also make sure furnace filter is cleaned, if none of this works refer to installation manual to see if humidifier was sized and installed properly, Good luck.

The 24Va 12Vac transformer should function as well. with absolutely no problem.

Depends on what Volts and VA your DS3200 humidifier works on. If it is the same, no problem but if it is different don't do it.

If your humidifier is working properly, then the problem lies outside of the humidifier. For example how long does your furnance run when the thermostat calls for heat? If your furnace is oversized for your home, it will heat your home relatively quickly, and turn off, while your humidifier does not have a chance to work long enough for it to increase the humidity. If this is the case, you could try to set the thermostat to run the fan in manual mode instead of automatic. This will give the humidifier a chance to increase the humidity.

Hope this helps.

Could be a couple of things. Transformer can be bad. Try connecting the two wires (usually wired red and white) from the transformer to terminal W and C on the circut board. Your bypassing the transformer and if installed a current sensing relay. The furnace transformer will/should handle the extra load. Turn on the furnace, if still not working, loosen the water supply line at the water solenoid on the humidifier, if water flows out then your supply valve isn't clogged, if no water then try screwing in the needle on the supply valve all the way in then back out. If still no water then the valve is clogged. If all is good then it looks like the water solenoid is bad or wiring to valve/humidifier control. Don't find the controls bad that often. Have fun!

Turn the humidistat all the way up. This is the test position that will cause it to run continuously. The blower or furnace must be running, depending on how it is wired. If the humidifier has never been serviced in five years, call a professional. The orifices will plug and pad deteriorates after about a year. These need yearly maintenance to operate correctly.

sounds like either the motor is off balance
or is going bad again
either way id be on the phone to the guy who did the rapair
more than likely the set screw on the sqiral cage came loose and now its vibrating

If the manufacture says it is the IFC then you should have the IFC checked by the company who installed it if it is under warranty still