Form O-Y P/N 273647R5, Page 37
Condensate Drain - High Efficiency Heat Section
Check the condensate drain.
Clean the drain and trap:
1. Open the cleaning ports and use the brush provided to clean the drain.
2.
To clean the trap and float, unscrew the retaining ring and remove the bottom
section of the trap. Remove the float and spring. Clean the parts with soapy water.
3.
Reassemble the trap by inserting the spring and float into the bottom trap section.
Position the bottom section in to the top and secure with the retaining ring.
4.
Reconnect the trap and check for proper flow.
Condensate Drain Pressure Switch (See FIGURE 23, page 32)
Function:
If the condensate drain is blocked causing the sensing pressure to be
outside the switch setpoint, the pressure switch will shutoff the gas valve. The gas
valve will remain off until the problem is corrected.
Service:
If it is determined that the condensate pressure switch needs replacing,
use only a factory-authorized replacement part that is designed for the heater. See
FIGURE 23,
page 32
for location.
Condensate Drain
Pressure Switch
5.2 Combustion Air
and Venting
Combustion Air
Proving Switch (see
table on page 38)
The gas heat section is power vented. Presence of combustion air pressure is moni-
tored by a combustion air proving switch located in the heat section.
The combustion air proving switch is a pressure sensitive switch that monitors air
pressure to ensure that proper combustion air is available. The switch is single pole/
single throw with the normally open contacts closing when the proper airflow is
sensed in the system.
On start-up when the heater is cold, the sensing pressure is at the most negative
level, and as the heater and flue system warm up, the sensing pressure becomes
less negative. After the system has reached equilibrium (about 20 minutes), the sens-
ing pressure levels off.
If a restriction causes the sensing pressure to be outside the switch setpoint, the
pressure switch will function to shut off the main burners. The main burners will
remain off until the system has cooled and/or the flue system resistance is reduced.
The table on page 38 lists the approximate water column negative pressure readings
and switch set points for sea level operating conditions.
DANGER
Safe operation requires proper venting flow. Never bypass the
combustion air proving switch or attempt to operate the heat
section without the venter running and proper flow in the vent
system. Hazardous condition could result.
Service:
if the pressure switch needs to be replaced, use a factory-authorized
replacement designed for the application.
Optional Gas
Pressure Switches
Location:
Low pressure switch is at the entrance to the gas train. The high pressure
switch is at the burner end. See
FIGURE 24,
page 33
or 25
, page 34.
Function:
Monitors gas pressure and shuts down the heat section if gas pressure
becomes too low or too high. The low pressure switch is an auto reset type and is set
at 50% of the maximum manifold pressure. The high pressure switch requires manual
reset and is set at 125% of manifold pressure.
Service:
There are no replaceable parts and the settings are non-adjustable. If
replacement is required, use identical factory-authorized safety switches.
Low
P/N 204375
High
P/N 204279
P/N 234712
Set Point 0.10 I.W.C.
Condensate Drain
Trap P/N 271064
