is normally caused by short cycling, a restricted drain, or back pressure. The foam, generated in these instances, is conductive and may lead to false full cylinder indication if the level of the foam approaches the top of the cylinder.
BACK PRESSURE: The restriction of steam flow caused by long steam runs, improperly sloped steam lines, elbows changing the direction of steam flow from horizontal to vertical without a drain leg, any plumbing detail allowing the accumulation of condensate, undersized steam line, improper steam distributor, downward air flow onto the distributor causing excess static pressure at the steam outlets, or high static pressure ducts (not probable). To overcome excess static pressure in the duct, a fill cup extension kit should be used. In down flow applications, a down flow distributor should be used, but in some cases the fill cup extension will also be required.
RESET UNIT (HUMIDIFIER): To reset the humidifier, the auto on/off/drain switch at the front of the humidifier should be switch to the “Off” position for a minimum of five seconds and then switched back to the “On” position.
MONITORED LEG: Refers to the primary wire to the cylinder which loops through the current sensing devise of the main PCB. This wire is terminated at the red cylinder plug at the cylinder.
STARTING POINT
Auto On/Off/Drain switch in “On” position - unit will not fill:
When the on/off control circuit is made and the “auto on/off/drain” switch is pushed to “on”, the 24 volt holding coil of the primary contactor should energize. The resulting magnetic pull closes the high voltage contacts with a distinct and audible “clunk”. If the contactor will not make, then inspect the following while referring to the wiring diagram:
1.Check for 24 Vac across terminals 18 and 26 on PC board.
2.Jumper the humidistat on external control terminal strip. If contactor operates, then control system is at fault.
3.The low voltage 3 amp fuse located in the control box could be blown.
4.The contactor holding coil could be open or shorted.
5.The switch could be defective.
Recheck that the “auto on/off/drain” switch is still at “on”. If it is, then shut off the main disconnect and check fuses or breaker of the main disconnect. If they are serviceable, turn power back on.
To test for a defective “auto on/off/drain” switch, connect a wire from the fuse directly to terminal 6 on the external controls strip. If the contactor activates, the “on” side of the switch is defective. If the contactor does not activate, the PC board could be defective.
If the 3 amp control fuse blows when the wire from the fuse touches terminal 6 on the external controls strip, contactor holding coil could be shorted. Replace contactor if necessary.
Return wires to normal.
After the necessary components have been replaced and the contactor pulls in, there is line voltage to the cylinder and the control sequence can begin.
Approximately 30 seconds after the contactor pulls in, the fill valve coil should energize. There is also a visible fill relay on the printed circuit board. It is the one located farthest from the C.T. core. The points on this relay must be touching in order for the fill valve coil to be energized.
If the points will not touch after the
Having changed the necessary components, water starts filling the cylinder and begins to submerge the electrodes. Because of the high voltage across the electrodes, the water can now conduct electricity.
Red “Change Cylinder” light on - Water at top of cyl- inder:
This is a common occurrence on
If the cylinder is old, it indicates end of cylinder life. Time to replace the cylinder. See “When To Replace The Steam Cylinder” section of this manual.
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