Thomas & Betts UDAP, UDAS dimensions Instructions

FIGURE 10 - Gas connection is at the pipe nipple that extends outside the cabinet

Illustration shows both a vertical and horizontal gas supply; requirements are the same.

Valve Outlet or

Orifice Pressure

Setting

NOTE: Gas Conversion Kits are available for changing from propane gas to natural gas or natural gas to propane gas. A factory- authorized conversion kit MUST be used.

Check Valve Outlet Pressure (can only be done after heater is operating)

NOTE: If operating at high altitude, outlet pressure requires adjustment. Follow instructions on page 14.

Leak-test all connections by brushing on a leak-detecting solution.

Ground
Joint Union	Manual shutoff
To Gas Valve
(inside the
cabinet)
Drip		From Gas Supply
Leg		(horizontal or vertical)
Pipe nipple extending
outside the cabinet.		Manual shutoff
To Gas Valve
(inside the
cabinet)
	Ground	Drip
	Joint	Leg
	Union

Measuring valve outlet gas pressure cannot be done until the heater is in opera- tion. It is included in the steps of the "Check-Test-Start" procedure in Paragraph 24. The following warnings and instructions apply.

WARNING: Valve outlet gas pressure must never exceed 3.5" w.c. for natural gas and 10" w.c. for propane gas.

For Natural Gas: When the heater leaves the factory, the combination gas valve is set so that the valve outlet gas pressure for a single stage valve or high fire of a two stage valve is regulated to 3.5" w.c. Inlet supply pressure to the valve for natural gas must be a minimum of 5" w.c. or as noted on the rating plate and a maximum of 14" w.c.

For Propane Gas: When the heater leaves the factory, the combination gas valve is set so that the valve outlet gas pressure for a single stage valve or high fire of a two stage valve is regulated to 10" w.c. Inlet supply pressure to the valve for propane gas must be a minimum of 11" w.c. and a maximum of 14" w.c.

Before attempting to measure or adjust valve outlet gas pressure, the inlet supply pressure must be within the specified range both when the heater is in operation and on standby. Incorrect inlet pressure could cause excessive valve outlet gas pressure immediately or at some future time. If natural gas supply pressure is too high, install a regulator in the supply line before it reaches the heater. If natural gas supply pressure is too low, contact your gas supplier.

Instructions

1)Locate the 1/8” output pressure tap on the valve (See FIGURE 11, page 14). With the manual valve turned off to prevent flow to the gas valve, connect a manometer to the 1/8" pipe outlet pressure tap in the valve. NOTE: A manom- eter (fluid-filled gauge) is recommended rather than a spring type gauge due to the difficulty of maintaining calibration of a spring type gauge.

2)Open the manual valve and operate the heater. (NOTE: On Model UDAS, depress and hold the door safety switch.) Measure the outlet pressure of the gas valve. Normally when operating at sea level, adjustments should not be neces- sary to the factory setting. (For high altitude settings, see next paragraph.)

If adjustment is necessary, remove the cap from the adjustment screw(s). Set pressure to correct settings by turning the regulator screw IN (clockwise) to increase pressure. Turn regulator screw OUT (counterclockwise) to decrease pressure.

Form RZ-NA I-UDA, Mfg #195673 Rev 5, Page 13