One Permanent Opening Method; Opening A Louver Through The Mfc Series Boiler - Watts AERCO MFC Series Pre-Installation Application Manual

MFC Series Boiler Vent and Combustion Air Guide

4.4 One Permanent Opening Method

One permanent opening shall be provided, commencing within 12 inches (300 mm) of the top of
the enclosure. The appliance shall have clearances of at least 1 inches (25 mm) from the sides
and back of the appliance, and a clearance of 6 inches (150 mm) from the front. The opening
shall communicate with the outdoors directly or through a vertical or horizontal duct to the
outdoors or spaces that freely communicate with the outdoors (as shown in Figure 6) and shall
have a minimum free area as follows:
•
2
1 inch per 3,000 BTU/hr (700 mm
in the space.
Figure 6: All Combustion Air from Outdoors through Single Combustion Air

4.5 Opening a Louver Through the MFC Series Boiler

A louver can be opened using the auxiliary relay contacts, part of the MFC burner controls. These
contacts are provided by a single pole double throw (SPDT) relay that is energized when there is
a demand for heat and is de-energized after that demand is satisfied. The relay contacts are rated
for 120 VAC at 5 amps, resistive.
NOTE:
Do NOT power the louver directly using the Auxiliary Relay. An external relay (supplied by
others) must be employed for this purpose. The boiler power cannot support external
accessories.
TAG-0080_OG • GF-148-V •
2
/kW) of the total input rating of all appliances located
Opening
Technical Support • (800) 526-0288 • Mon-Fri, 8 am - 5 pm EST
3/29/2023
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