Thomas & Betts LDAP 1200 Gas, Pressures, cont’d, Instructions, Check Valve Outlet, is operating

12. Gas				Instructions
	Pressures			the manual valve turned off to prevent flow to the gas valve, connect a manom-
				1) Locate the 1/8” output pressure tap on the first valve (See FIGURE 8). With
	(cont’d)			eter to the 1/8" pipe outlet pressure tap in the valve. NOTE: A manometer (fluid-
Check Valve Outlet				filled gauge) is recommended rather than a spring type gauge due to the difficulty
Pressure (can only				of maintaining calibration of a spring type gauge.
be done after heater				2) Open the manual valve and operate the heater. Measure the outlet pressure of
				the gas valve. To measure low-stage pressure on a Size 400 unit equipped with a
is operating)
				two-stage valve, disconnect the wire from the “HI” terminal on the valve. (Be
NOTE: If operating at high				sure to reconnect wire after testing.)
				Normally when operating at sea level, adjustments should not be necessary to the
altitude, outlet pressure
				factory setting(s). (For high altitude settings, see below.) If adjustment is neces-
requires adjustment. Follow
				sary, remove the cap from the adjustment screw(s). Set pressure to correct
instructions below.
				settings by turning the regulator screw IN (clockwise) to increase pressure. Turn
NOTES: If installation is				regulator screw OUT (counterclockwise) to decrease pressure.
				3) If installing a Model LDAP 800, repeat to verify outlet pressure on second valve.
above 6000 ft (1830M), a
				If installing a Model LDAP 1200, repeat to verify outlet pressure check on
high altitude pressure switch
				second and third valve.
is required on each heat
				Derate by Valve Outlet Pressure Adjustment for High
section (all sizes). See
Paragraph 5.				Altitude Operation
The main combustion air				Instructions for HighAltitude Derate
pressure switch (Sizes 800				1. Determine the required valve outlet pressure for the elevation where the heater
and 1200 only) does not need				will be operating. If unsure of the elevation, contact the local gas supplier.
to be changed for high				Valve Outlet Pressure Settings by Elevation
altitude installation.
					Manifold Pressure Settings by Altitude for the UNITED STATES
FIGURE 8 - Top View of				Altitude		Natural Gas (inches w.c.)		Propane Gas (inches w.c.)
						Single-Stage and	Two-Stage	Single-Stage and	Two-Stage
Valves showing Outlet				Feet	Meters
						Two-Stage High Fire	Low Fire	Two-Stage High Fire	Low Fire
Pressure Tap and
				0-2000	0-610	3.5	2.0	10.0	5.6
Adjustment Locations				2001-3000	611-915	3.1	1.7	8.8	5.0
				3001-4000	916-1220	3.0	1.7	8.5	4.8
	Single-Stage Valve
				4001-5000	1221-1525	2.8	1.6	8.1	4.6
				5001-6000	1526-1830	2.7	1.5	7.7	4.4
	Output	1/8” Output
				6001-7000	1831-2135	2.6	1.5	7.4	4.2
	Adjustment	Pressure Tap		7001-8000	2136-2440	2.5	1.4	7.1	4.0
	Screw			8001-9000	2441-2745	2.4	1.3	6.7	3.8
				9001-10000	2746-3045	2.4	1.3	6.7	3.6
	Inlet
					Manifold	Pressure Settings by Altitude for CANADA
	Pressure			Altitude		Natural Gas (inches w.c.)		Propane Gas (inches w.c.)
	Tap			Feet	Meters	Single-Stage and	Two-Stage	Single-Stage and	Two-Stage
						Two-Stage High Fire	Low Fire	Two-Stage High Fire	Low Fire
	Two -Stage Valve (optional			0-2000	0-610	3.5	2.0	10.0	5.6
				2001-4500	611-1373	2.8	1.6	8.1	4.6
	on Model LDAP 400 only)
				2. Locate the 1/8” output pressure tap on the first valve (See FIGURE 8). Turn
	Adjust High	Adjust Low
				the knob on the top of the valve to “OFF”. Connect a manometer to the 1/8"
		Pressure
	Pressure			pipe outlet pressure tap in the valve. Use a water column manometer that is
		Output
	Output			readable to the nearest tenth of an inch.
				3. Single-Stage and Two-Stage High Fire - Turn the knob on the top of the
				valve to “ON”. Remove the cap from the pressure adjusting screw and adjust
				the gas train pressure to the pressure selected from the table above. Adjust
	Inlet			pressure by turning the regulator screw IN (clockwise) to increase pressure or
				OUT (counterclockwise) to decrease pressure.
	Pressure
		1/8” Output		Two-Stage Low Fire - Disconnect the wire from the “HI” terminal on the gas
	Tap
				valve and check the low fire pressure. Turn the regulator screw to adjust the low
		Pressure
				fire outlet pressure to the “Low Fire” pressure selected from the table. Re-
		Tap
				connect the wire to the gas valve.
	Form RZ-NA-I-LDAP, P/N 207733 (Rev		2), Page 12