Bth 199 & 250 Intake Air Connection - A.O. Smith BTH-120 Instruction Manual

Bth 199 & 250 intake air connection
BTH 199 and 250 models are factory equipped with a unique
Combustion Blower and intake air connection Tee fitting. The Tee
is a 3" x 3" x 1/2" fitting. The intake air connection Tee fitting has a
hose barb installed in the 1/2 inch branch to connect the Blocked
Intake Air switch sensing tube, see Figure 15.
FACTORY INSTALLED
INTAKE AIR TEE FITTING
1/2 INCH
BRANCH
HOSE BARB FITTING FOR
BLOCKED INTAKE AIR
SWITCH SENSING TUBE
COMBUSTION BLOWER ASSEMBLY
199,000 & 250,000 Btu/hr MODELS
Ensure the hose barb installed in the Tee fitting is not facing
down towards the ground (180° - 6 o'clock position) before venting
installation begins. The barb fitting must be angled between 90°
and no more than 130° as shown in Figure 16. If the barb fitting
is facing down, residual condensate that occasionally forms in
the intake air pipe can drain into the Blocked Intake Air switch
through the attached sensing tube and damage the switch. This
condition can also lead to Blocked Intake Air fault conditions and
associated control system lock outs.
END VIEW
CORRECT ORIENTATION
INTAKE AIR TEE FITTING
COMBUSTION BLOWER
FERNCO
COUPLING
figure 15
90° TO 130°
figure 16
The intake air Tee fitting is factory installed with the 1/2 inch
branch and hose barb angled to the right at approximately 130°
when viewed from the end, see Figure 16. The Tee fitting's
1/2 inch branch and hose barb must not be angled any lower
(towards the ground) than this factory specification. Angling
higher, up to a 90° position, will not adversely affect operation
and is acceptable.
inspect/adjust intake air tee fitting
Inspect the angle of the Tee fitting's 1/2 inch branch and hose
barb while viewing from the end of the Tee, see Figure 16. If the
angle of the Tee fitting 1/2 inch branch and hose barb is lower
than shown, adjustment will be necessary. To adjust the intake
air Tee fitting angle follow the steps listed below.
adjustment procedure:
1. Ensure the water heater is turned off at the on/off switch on
the front of the water heater.
2. Disconnect the Blocked Intake Air switch sensing tube, see
Figure 4 on page 9 for location.
3. Loosen the large hose clamp on the Fernco coupling that
connects the intake air connection pipe to the Combustion
blower, see Figure 17.
4. Adjust the angle of the Tee fitting so that the 1/2 inch branch
and hose barb are at the proper angle as shown in Figure 16.
5. retighten the large hose clamp on the Combustion Blower
intake air Fernco coupling,
6. reconnect the Blocked Intake Air switch sensing tube making
sure the sensing tube is securely connected at both ends and
is not kinked.
LARGE HOSE
CLAMP
INTAKE AIR
TEE FITTING
INTAKE AIR CONNECTION PIPE
199,000 & 250,000 Btu/hr MODELS
23
FERNCO
COUPLING
3 INCH PVC
figure 17