Install Instructions

47
109837-01 - 5/20
PVCG-C
Installation, Operating & Service Manual
Table 12.2: Sea Level Pressure Switch Settings
FACTORY PN
APPROX. MAKE
SETTING (inches w.c.)
BREAK SETTING*
(inches w.c.)
109839-01 1.32 1.24
*Settings shown are based on “plus tolerance” - actual setting may be lower.
11. Clean the flue passageways using a stiff bristle
brush. Be certain that all foreign material is
removed from the gaps between the pins.
12. Clean the bottom surfaces of the heat
exchanger.
13. Put a light in the combustion chamber and look
through the flue passages from the top to verify
that they have been thoroughly cleaned.
14. Replace the canopy gasket strips. If desired,
RTV-732 silicone sealant with a 500F intermittent
duty temperature rating may be substituted
for this rope gasket. The canopy must be
thoroughly sealed to the heat exchanger.
15. Reassemble the rest of the boiler in reverse
order of above. Be sure to reinstall the vent
securing screw removed in step 3. If this screw
has deteriorated, replace it.
C. Service Notes
1. Pressure Switch – This boiler is equipped with a
differential pressure switch which makes when
there is adequate flue gas flow through the
boiler. This switch measures the pressure drop
across an orifice plate inside the flue collector;
the higher the flue gas flow through this plate,
the higher the pressure drop. The N.O. contacts
on the pressure switch make, allowing the boiler
to fire, when the pressure drop across the flue
collector orifice plate switch exceeds the “make
setting” shown in Table 12.1. Once the switch is
made, the boiler will fire as long as the pressure
at the switch is above the “break setting” shown
in Table 12.2. The pressure at both pressure
switch tappings is actually below atmospheric
(“negative”) with the pressure at the front flue
collector tap being the more negative of the two
pressures. Figure 12.3a shows the pressure
switch connections.
Figure 12.3b shows the correct method of
reading the pressure across the pressure switch
tappings. It is normal for the pressure reading
across the switch to drop as the boiler heats up.
12 Service and Maintenance (continued)