PB Heat Gas Boiler Main GAS Valve Operation, Recommended Vent CO² Settings Firing Gas Type Rate

GAS PIPING

Table 4.4: Maximum and Minimum Fuel Pressure

Gas	Pressure (inches of water)
Type	Minimum	Maximum
Natural	3.7	13.5
LP	3.7	13.5

3.To check the gas supply pressure on the gas valve:

a.Turn off the power at the service switch.

b.Turn off the gas shutoff valve.

c.Using a flat screwdriver, turn the screw inside the inlet pressure tap fitting (see figure 4.4 and 4.5) one turn counterclockwise.

d.Attach the manometer tube to the pressure tap fitting.

e.Open the gas shutoff valve and start the boiler.

f.Read and record the gas pressure while the boiler is firing.

g.Turn off the boiler and gas shutoff valve

h.Remove the manometer tube from the pressure tap fitting and turn the screw to close the internal valve.

i.Turn on the gas shutoff valve and boiler service switch.

4.All gas piping must be leak tested prior to placing the boiler in operation.

a.If the leak test pressure requirement is higher than the maximum inlet pressure noted in Table 4.4, the boiler must be isolated from the gas supply piping system.

b.If the gas valve is exposed to pressures exceeding 13.5" of water, the gas valve must be replaced.

5.Install the boiler such that the gas ignition system components are protected from water (dripping, spraying, rain, etc) during operation and service (circulator replacement, condensate trap cleanout, and control replacement, etc).

WARNING

Do not adjust the throttle screw without monitoring the carbon dioxide (CO²) and carbon monoxide (CO) in the vent pipe. Vent CO emissions above 400 ppm are in excess of most safety standards.

b.For both gas valve arrangements, turning the throttle screw clockwise will decrease the gas flow

(decreasing CO²) and turning it counterclockwise will increase the gas flow (increasing CO²).

c.The recommended CO² settings are given in Table 4.5. In no case should the boiler be allowed to operate with CO emissions in excess of 150 ppm.

2.Refer to Section 5, Venting for information on obtaining vent samples from this boiler.

Table 4.5: Recommended Vent CO² Settings

	Firing			Vent CO²
Gas Type	Rate				Vent CO
Natural	Low		8-1/2% to 9-1/2%		< 50 ppm
	High		8-1/2% to 9-1/2%		< 100 ppm
LP	Low	9-1/2% to 10-1/2%			< 50 ppm
	High	9-1/2% to 10-1/2%			< 100 ppm

Figure 4.4: Gas Valve/Venturi PI-T50/PI-T80

E. MAIN GAS VALVE - OPERATION

1. Figure 4.4 shows an illustration of the gas valve/venturi assembly for the Pinnacle PI-T50 and PI-T80 and Figure 4.5 shows an illustration of the gas valve/venturi assembly for the PI-80, PI-140, and PI-199.

a. The throttle screw on either of these valves should not be adjusted without a means to measure carbon monoxide (CO) and carbon dioxide (CO²) emissions.

Figure 4.5: Gas Valve/Venturi PI-80, PI-140, PI-199

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