Table 6 – Troubleshooting Guide
Problem
Possible Cause
action
General operating
problems . Humidifier
will not turn on or
turn off .
Field-wired terminal
connections .
Verify L1, N/L2 and ground connections are properly wired and appropriate voltage is present .
Check HUMIDISTAT and (if used) FAN PACK terminal connections are tight and properly wired .
HUMIDISTAT terminals must be connected to an on/off device . Control circuit board will be damaged
if 24 volts are connected to HUMIDISTAT terminals .
Check wiring connections and settings on Accessory items such as high limit switch and airflow
proving switch .
Internal connections .
Check electrode and high water probe connections on the top of the canister .
Make sure blue/white wire jumpers (2) connecting Control PCB and Current Sensing PCB are secure
and properly oriented . See Wiring diagram
figure 10
,
11
or
12
.
Make sure ribbon cable from membrane switch is securely plugged into control circuit board .
Check that terminals from internal components are securely attached to proper tabs on circuit boards .
Make sure one of the electrode wires extends through toroid ring on current sensing circuit board .
Make sure Black/white wire from L1 is attached to terminal that matches input voltage .
No power to humidifier .
Check main power supply and switch .
Ensure breaker is sized appropriately for the amperage draw .
Check for proper voltage across L1 and N/L2 terminals .
Humidifier not turned on .
Make sure front cover is attached to engage safety interlock switch . Press On/Off button .
Make sure ribbon cable from membrane switch is not damaged and is securely plugged into the
control circuit board .
No power to 24 volt control
circuit .
Check reset switch on transformer .
With humidifier energized, check for 24+/- 6 volts across J2 & J5 terminals . If okay, check for 5 volts
DC 5V and GND test points on control circuit board .
If 5 volts DC are present replace membrane switch . If not, remove blue/white wire jumpers and check
DC voltage 5V and GND test points again .
If 5 volts DC are present, replace current sensing circuit board . If not, replace control circuit board .
Steam Light does not
turn on .
Call for humidity not being
received .
Check ADHC wiring and setting . (Do not leave ADHC in TEST mode .)
Check wiring and settings of high RH limit switch and airflow proving switch .
Water is leaking from
humidifier .
Loose plumbing
connections .
Check water supply connection at fill valve inlet . Tighten as needed .
Check internal hose clamp connections . Reposition clamps and tighten as needed .
Check steam hose connection on top of canister . Tighten clamp as needed .
Hoses are blocked .
Check internal hoses and eliminate kinks or blockage .
Drain hose is blocked .
Make sure drain hose has constant downward slope and is not blocked .
Water constantly runs
down drain .
Malfunctioning drain valve . Check valve function using the TEST MODE section of this manual .
Debris in drain valve
preventing it from closing .
Remove canister and clean debris from drain valve .
O-ring in drain valve is not
properly seated in groove .
Remove canister and check O-ring for damage . Replace O-ring as necessary . Ensure O-ring is properly
seated in its groove .
Water is flowing from fill
cup overflow port .
Check internal hoses and eliminate kinks or blockage .
Disassemble brass fitting in feed line between inlet valve and fill cup . Make sure small rubber flow
orifice is in place in brass fitting .
High static pressure in duct
is causing back pressure in
canister .
Make sure dispersion tube is not discharging into duct with greater than 2 .0 in .wg static pressure .
Make sure dispersion tube tubelets are pointed up .
Humidifier is filling
and water is flowing
down drain but drain
light is not on .
Internal wiring connections . Make sure blue/white wire jumpers (2) connecting Control PCB and Current Sensing PCB are secure and
properly oriented . See Wiring diagram
figure 10
,
11
or
12
.
High static pressure in
steam line is causing back
pressure in canister .
Install a tee and drain trap in any low points in the steam line . See
figure 4
.
CHeCkInG SySTeM oPeRaTIon & TRoUbleSHooTInG
(ConTInUeD)
21