Nature's Comfort NCB-80 Installation And Operating Manual - page 12
Page 12 of 34
D. Plumbing Hook Up
Plumbing connections should be well insulated after installation. Cover bottom access holes as
well.
Minimum pipe size permitted is 1”. Install the outgoing pex line on the pump flange that is already
mounted to the lower end of the circulation pump. Install the return line on the 1” 90 located to the
left of the rear upper heat exchanger tube access cover. Add a valve to the return line so if
repair or service is needed on lines or equipment, the water in the boiler can be isolated
without having to be drained. (Valves and PEX fittings can be purchased from Nature’s Comfort.)
Install a fill line from the domestic water into the return line using a T, 2 valves and a union to
disconnect or a backflow preventer when not using to keep 100% isolated so no boiler water can
ever enter the domestic side.
Use sweeping bends for PEX pipe keeping 90’s to a minimum (no more than 6) as each one adds 1
foot of head pressure, reducing the rate of water flow. For tight radiuses use ¾” rubber heater hose
in short lengths (fits 1” PEX fittings and is available from Nature’s Comfort).
For a forced air system, run the line from the pump first to the heat exchanger for the domestic hot
water then to the one in the furnace plenum. For a hydronic radiant system, reverse this order.
Note: For larger homes, 1-¼ pipe may be needed for maximum BTU output. A 1-¼” pipe can carry
up to 37% more BTUs due to higher water flow. The fittings above would need to be changed to
accommodate 1-¼” Pex. The Armstrong E9.2 pump available from Nature’s Comfort has the ability
to do this in a 1” pipe within distance & height limitations.
E. Wiring the Boiler
A qualified electrician must wire this boiler in accordance with the National Electrical Code.
A dedicated 15amp, 115vac ground-fault protected circuit needs to be installed to power the lower
outlet. Land power & neutral wires to the back of the outlet and wire nut the ground wire to the green
wire that is fastened alongside the ground of the outlet (see earlier diagram). The size and type of
electric wire to be installed depends on the distance from the boiler to the house. If the boiler is less
than 100 feet from the house, #14 AWG UF cable is the smallest wire that may be used. If the distance
is greater than 100 feet, #12 AWG UF cable must be used. A maximum of 5 amps is used by the boiler
if all standard equipment is running and dual 100watt light bulbs are used (3 amps if solar light was
included). The extra outlets will provide a total of 10amps for convenience use.
Plug the control plug into the lower outlet to power the upper outlet and controls.
F. Forced Air Systems - Thermostat Wiring
The next example drawings are for controlling the blower on a forced air system independently of
the existing heat source (i.e. propane, electric, fuel oil, etc). Nature’s Comfort can provide diagrams
for other types of control setups as well upon request (fee may apply for custom diagrams).