True Steam Direct Injection Model # HM506 service light blinks 6 times before remaining a solid color. What does that mean? I realise that the unit is detecting a system fault, would just like to know before calling for service.

More than likely, mineral scale has built up inside the tank and the mist tubing.

To clean it, turn the unit OFF & unplug it. Empty any remaining solution that's in the tank and refill it with a 50/50 solution of White Vinegar and Bottled Distilled Water. Plug the unit in and turn it ON. Allow it to run for 5 minutes, then turn unit OFF and allow it to soak for 30 minutes to and hour.
Then turn the unit back ON. If the water spitting has stopped, run the unit unit is half empty. Turn it OFF, unplug it and empty any of the remaining solution. Refill with Bottled Distilled Water and run it until it's empty. Doing so, will flush out any of the remaining solution and scale.

In the future, it is best to use Bottled Distilled Water, rather than tap water. As the Distilled Water does not contain any harmful minerals or chemicals.

Hope this helped you and thanks for choosing FixYa.

The easiest ans simplest way to clean it, is too mix a 50/50 solution of White Vinegar & Bottled Distilled Water (enough to fill the tank) and fill the the tank with the solution. Allow it to set for 30 minutes, then turn the unit ON. Allow it to run, until the tank is half empty. Pour out the remaining solution and fill with the Bottled Distilled Water Turn the unit ON and run until the tank is almost empty. Following these instruction will remove all the lime and calcium build up in the unit.

Tip: Using bottled Distilled Water rather than Tap Water, will totally eliminate calcium and lime buildup.

I hope this helped you and thanks for choosing FixYa.

The problem is more than likely due to a calcium and mineral build up in the tank and the tubing.
Hopefully, it's not to late to do something about it. So follow the instructions below,

Unplug the unit.

Remove any remaining water from the tank.

Mix a 50/50 solution of White Distilled Vinegar and Bottled Distilled Water (enough to fill the tank) and pour the solution into the tank. Allow t to sit overnight. In the morning, plug the unit in and turn it ON. If it doesn't start producing steam, turn the unit OFF, unplug it and empty the tank. Mix more solution as described above, pour it in the tank and allow it to set for 3 or more hours. The plug the unit in and turn it ON. Hopefully, this time, it will start to produce steam. If it does allow it to run until the tank is half empty. Turn the unit OFf and empty the remaining solution from the tank. Refill the the tank with Bottled Distilled Water and run the unit until it's empty. That will flush the system.

In the future, I would highly recommend the use of Bottled Distilled Water, rather than using tap water.

If the above didn't solve the problem, it's time to buy a new humidifier and use Bottled Distilled Water in it.

The unit may simply has a calcium scale build up and it's blocking the water passage. To clean it, empty in water remaining in the tank. Mix a 50/50 solution of White Vinegar and Bottled Distilled Water and fill the tank. Allow it to soak for at least one hour, then turn the unit ON. Place you hand in front of the misting nozzle to see if it's working. If you don't feel any mist, turn the unit OFF and allow it sit over night. If you do feel mist, allow it to run until the tank is 3/4's empty Turn the unit OFF, pour out the remaining solution and refill with Bottled Distilled Water. Run the humidifier until it's empty. This will flush the system entirely. In the future, I would recommend you use Bottled Distilled Water, instead of Tap Water. If you do, you won't have to descale the unit any more.

Hope this helped you, please let me know. Thanks.

Is the saddle valve on the hot water line open? If so can you hear the water valve open? If it clicks that doesnt mean it is opening.

You have a cool mist humidifier there is no steam. Please read manual or look up unit on internet

there is a bank of dip switches to the left of the low voltage connections almos middle of humidifer on the green control board the numbers are clearly above the switches

I had the same problem.
I replaced the solenoid which resulted with the same problem.
I then blocked the drain using a ball valve, that resulted in the humidifier overflowing.
I do have a fault code (3 blinks) indicating failure to fill tank.
However, if this were true, blocking the drain would have solved this problem.
I have replaced the unit with a new one, and it is now working perfectly.
If you have covered all these bases then I suggest replacing your unit. Hopefully it's under warranty.
Cheers, Rich

The reset is to place the controller in the "test/reset" position. The furnace must be in heat mode and operating at the time. The green light will blink for about 1 minute if operating properly, then cut off when placed in a normal setting.