10/22/2008
8
BI302B
WARMFLO AQUASTAT OPERATION
Sensor cable installation – see previous paragraph, Mechanical.
Determine from floor tubing supplier design outline the desired floor temperature. Typically this relates to floor covering
and tube placement design. Set the aquastat set point for desired warm water outlet.
The temperature set point is selected by a small screwdriver switch on the control board. Use the following chart:
Switch Position
Set Point
0 85
1 95
2 105
3 115
4 125
5 135
6 145
7 150
The green LED on the circuit board is on whenever Stage 1 electric element is on. This can either be full on, pulsing at a
slow rate, or full off.
TROUBLESHOOTING HELPS
Monitor – the green LED to the left of the dial switch not only indicates the first element operating on/off, but also
provides some sensor quality information. If this LED is pulsing, there is either a shorted sensor, open wire to the sensor,
or some sensor wiring error. The internal logic is not receiving temperature information from the sensor tip.
The default for a bad sensor – boiler operates at half capacity, stage 1 on, stage 2 off.
Sequence
At heat call, elements 1 and 2 are full on.
As the outlet temperature approaches the set point, element 1 begins to pulse modulate.
At set point element 1 is off or 0%.
At +5° above set point element 2 turns off.
At set point element 1 again begins to modulate.
At 5° below set point element 1 is at 100% and element 2 would again turn on.
Mechanical hi-limit, top vessel screw-in, automatic reset
– this is at about 160° F, opens the red/white wire loop. This
can be monitored by the “Auto Reset” front indicator light. As the water cools to approximately 120° it should self reset
and restart.
Manual reset limits
– surfaced mounted to the top of the vessel, opens at 205° F. This actually opens the current carrying
leg to each element and prevents 240 power from reaching the element. This can be monitored from the “Manual Reset”
front indicator light.
To reset this device, notice a small shiny lever protruding from one side of the black insulator. Simply push this lever
inward and it should snap.
Comment:
These lights will only be active during a heat call and when the element relay is closed.
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 9 kW, full on.
