Watlow WATROD Screw Plug - Manual (Page 4)

WATLOW IND.
WATROD Screw Plug Installation & Maintenance Manual
I&M NUMBER: 316-42-10-1 Page: 4
Date:6/11/2008 Rev: 3.00
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WATLOW IND.n # 6 INDUSTRIAL LOOP RD. n HANNIBAL MO, 63401n PHONE 573-221-2816 n FAX 573-221-3723
Thermostats can be supplied with Screw Plug heaters. Consult the wiring diagram supplied with the heater
for the suggested wiring of thermostats. For safe operation of thermostats, consult Installation and
Maintenance manual for thermostats that is attached.
Thermostats should not be used as an "OFF" device; the use of a disconnect switch or circuit breaker is
recommended. The disconnect switch will allow isolation of the heater when maintenance of the heater is
required.
Start Up
Before energizing the heater the following items should have been checked with the heater power
disconnected:
1. Immersed section of heater is completely covered by liquid
2. Electrical termination is tight and wiring is per wiring diagram supplied with heater
3. Proper disconnecting means and fusing have been installed
4. The voltage rating of the heater is the same as that being applied
5. Megohm is within acceptable limits
6. Proper temperature controls and safety limiting devices are in place
7. Heater is securely installed in tank header and no leaks are visible
After applying power to the heater make sure that the system is being controlled properly before leaving it to
run unattended. Failure to do this could result in overheating resulting in personnel danger and fire.
Troubleshooting
PROBLEM Cause / Correction
No power available to heater Check disconnect switch to ensure it is in the "ON" position
and that fuses are not blown. Replace fuses if they are blown
Fuses blowing Check heater electrical rating. Applied voltage may be wrong
Check fuse rating. Fuses should be at least 25% more than full
load amperage.
Disconnect heater power source. Check the heater resistance
to ground. This should be no less than 1 Megohm. Refer to
Megohm checking.
Not enough power Check line voltage to ensure it is within specification
Check full line current if voltage is correct. If line current is lower,
the heater may be wired wrong or has open elements
Fluid not heating to desired Not enough Kw or incorrect voltage being applied
temperature Too much heat loss, higher wattage heater may be required
High limit tripping / alarm Not enough fluid flow
Too much Kw
Line voltage higher than designed / allowable
Preventative Maintenance
CAUTION: HAZARD OF ELECTRIC SHOCK. TURN ALL POWER TO HEATER OFF, USE APPROPRIATE
DISCONNECT LOCKOUTS AND ALLOW SYSTEM/HEATER TO COOL BEFORE PERFORMING ANY
MAINTENANCE
!