The boiler pump relay may require connection to a second electrical circuit (amperage greater than
4 amps). The boiler pump relay is rated for a maximum amperage load of ¾ horsepower. A
disconnect switch should be installed to isolate the boiler pump and the boiler pump relay power
supply.
Pumps can be switched on/off using the touchscreen controller, so there is no need for temporary
pump wiring during system filling / air purging. If pumps are hard-wired to the panel during the
system fill/purge phase, re-wire the boiler pump to the primary pump leads inside the wiring box so
the primary pump purge function is active.
In a new construction application, use a construction thermostat, or jumper with an in-line on/off
switch – for on/off management of the boiler. Do not just turn off power from the appliance, or its
moisture management routine will be interrupted (fan turns at ultra low rpm for 90 minutes after
burner shutdown). Treat it like a computer, where you do not just pull the plug when done. If a "low
airflow / check vent" error signal shows, check for (and remove) any water in the clear vinyl air
reference tubes. This has been seen occasionally at construction sites where the boiler has been
repeatedly de-powered wet.
The combined current of all load pumps connected through the on-board pump relays should not
exceed 10 amps. The control circuit board is protected using on-board field replaceable fuses.
Each pump is fused with a separate 5 Amp fuse. The Alarm contact is fused with a 5 Amp fuse and
the 24VAC boiler control circuit is protected with a 2 Amp fuse.
3.10.2.3 Variable speed boiler pumps
Variable speed boiler pumps are for connecting and managing speed in pumps that accept 0-
10VDC on 4-20 mA input signal.
Figure 39 Electrical box with new variable
speed connection - EX 400, EX 500
Figure 40 Electrical box with new variable
speed connection - EX 700, EX 850
3.10.2 120VAC line-voltage hook-up
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