CYCLONE Xi COMMERCIAL GAS WATER HEATER
BTH 120 thru 500 SERVICE HANDBOOK
A.O. Smith – Technical Training Department
28
Ashland City, Tennessee © 200
9
Servicing should only be performed by a Qualified Service Agent
316586-000
CONTROLS – GAS VALVE BTH 199 and 250
ADJUSTMENT PROCEDURE:
GAS PRESSURE
BTH 199 AND 250 MODELS
THE BTH 199 AND 250 MODELS
INCORPORATE A NEW GAS CONTROL,
WHICH OPERATES AT A MANIFOLD
PRESSURE OF 0"w.c. (0 kPa) FOR BOTH
NATURAL AND PROPANE GAS. SEE THE
GAS PRESSURE CHART ON PAGE 4.
THESE MODELS ARE CONFIGURED
PRIOR TO BEING SHIPPED FROM THE
FACTORY AND NO ADJUSTMENTS ARE
NECESSARY PRIOR TO STARTUP. THE
CONTROLLER MONITORS THE AIR
FLOW AND MAKES ADJUSTMENTS TO
THE FAN SPEED WHICH IN EFFECT
CONTROLS THE AMOUNT OF GAS
FLOW. THEREFORE, THE UNIT WILL
SELF ADJUST TO ACQUIRE THE
CORRECT AMOUNT OF INPUT.
"Supply gas pressure to the water heater
must not exceed a maximum of 10.5" w.c.
(295kPa) for natural gas, or 14" w.c. (3.45
kPa) for propane. The minimum supply gas
pressure is 4" w.c. (.98 kPa) for natural gas
and 9" w.c. (2.22 kPa) for propane gas."
Once the unit is installed and filled with water
and the inlet pressures confirmed, simply
turn the switch "on" and observe operation.
Cycle the unit "off" and "on" several times to
ensure proper operation.
HIGH ALTITUDE INSTALLATION
The BTH 199 and 250 models are suitable
for installation up to 10,100 feet above sea
level with no adjustments.
GAS ORIFICE
The BTH 199 and 250 models do not have a
natural gas orifice. A .230” orifice is used on
LP gas models.
Gas Control Without Orifice
Natural Gas
Venturi
Gasket
w/o orifice
Gas Control with .230” LP Orifice
Venturi
Gasket w/
LP Gas
Orifice
(.230”
Brass)
IMPORTANT NOTE
A supply gas pressure regulator
(service regulator) must be installed on
the gas supply line within 10' (305 cm)
of the unit.
