09/17/2014
9
BI308
TROUBLESHOOTING HELPS
Inside
monitor – there are two red LED’s on the inside labeled “STG1” and “STG2”. Each LED is an
indication of stages of boiler on/off.
Located near the thermostat connection is a red LED labeled “MANUAL-HL-OK”. This LED represents the
205° manual reset. If on, manual hi-limit is closed. If off, manual hi-limit is open.
Sequence
At heat call, pump turns on (control board top cube relay and orange wires).
Elements remain off for 30 seconds.
If the sensor is detecting supply water temperature approximately 8° less than set point, both stage 1 and
stage 2 turn on (stage 2 may have a 2-minute delay).
As the outlet temperature approaches the set point, element 1 begins to modulate.
At set point element 1 is off or 0%.
At +5° above set point element 2 is off.
At set point element 1 modulates.
At 5° below set point element 1 is at 100% and element 2 turns on.
Mechanical hi-limit, top vessel screw-in, automatic reset
– this is at about 190° F, opens the red/white wire
loop. This can be monitored by the “Auto Reset” front indicator light. As the water cools to approximately
150° it should self reset and restart.
Manual reset limits
– surfaced mounted to the top of the vessel, opens at 205° F. This opens all 24V control
power thus opening all element power relays. The observed action is the same as a blown fuse, no front panel
boiler power LED.
To reset this device, simply press the red button located on the limit switch.
Comment:
The hi-limit auto reset LED and utility off-peak LED are only on during an active heat call
(lower red LED on).
WARMFLO
®
TEMPERATURE BYPASS TROUBLESHOOTING OR TESTING
Adding a jumper between “W” screw terminal and tab marked “E” bypasses the temperature sensing and
WarmFlo control. In other words, with the jumper installed, a “W” input represents both stages, full on.
Note:
Basic 24V power must be present for the E-tab function to work.
AVAILABLE, ELECTRO INDUSTRIES, INSTALL PARTS OR KITS
EMB-BK
MINI-BOILER PLUMBING KIT BASIC
EMB-PK
MINI-BOILER INSTALL KIT PREFERRED
EMB-P2
PUMP KIT 1/25HP BOILER
ES-24-BR
STAT DIG SLAB/ROOM/ROOM 24VAC
WFS2
TEMPERATURE WATER SENSOR
EB-5415A ZONE
CONTROLLER
EMBH5636
REPLACEMENT CONTROL BOARD
4038 TRIAC
MODULE
5127 ELEMENT
RELAY
5541 TRANSFORMER,
24V/40VA
5576
AIR ELIMINATOR 3/4" ROLLAIRTROL
5456A
GAUGE PRES/TEMP 75 PSI/320DG F .25"
5453
VALVE RELIEF 30 PSIG .75” NPT MALE
5590
EXPANSION TAN K 40K BTU 20.1 GALLON
