Patterson-Kelley TBIG-03 owner manual Gas Pressure Adjustment, Leak Testing of Valves

Gemini™ Twin-Fuel Gas-Fired Boiler

4.4.5Gas Pressure Adjustment

Increase Decrease

Figure 4-7 Regulator

The gas pressure is set initially during a factory fire- test. A final adjustment must be made after the boiler has been installed, as follows:

See rating plate for the minimum and maximum gas pressure of the boiler.

Each boiler is furnished with three plugged taps in the gas train for test gauge connections. Two taps are lo- cated at the natural gas and propane manual shutoff valves and are for measuring the gas supply pressure (1/4" I.P.S.). The supply pressure during main burner operation must be greater than the minimum indicated on the rating plate (6 inches W.C. for natural gas, 6 inches W.C. for propane). The remaining tap is lo- cated downstream from the secondary manual shutoff valve at the elbow where the gas line enters the back of the cabinet and is for measuring the manifold gas pressure (1/8" I.P.S.).

If a replacement Lo-Hi-Lo actuator is required, follow manufacturer's instructions and pre-set the "Lo" fire setting of the actuator the same as the original actua- tor. This must be performed by qualified service per- sonnel.

To adjust gas pressure, first connect an appropriate pressure-sensing device at the manifold tap, then re- move seal cap from regulator. Turn adjusting screw clock-wise to increase pressure, counter-clockwise to decrease pressure. The manifold gas pressure on the

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"Rating Plate," affixed to the back of the cabinet, is provided only as a guide to the proper setting. The manifold gas pressure indicated on the "Factory Fire- test" label (affixed to the back of the cabinet) should be used to achieve the proper firing rate of the individual boiler as installed. Replace seal cap after adjustment.

4.4.6 Leak Testing of Valves

Annually test for by-pass leaks on all motorized gas valves. If gas flows when the motorized gas valve is closed it is defective.

motorized gas	secondary
	motorized
valve (natural
	gas valve
gas)
	secondary
	shutoff
	to burner

downstream leak test valve

upstream leak test valve

motorized gas valve (propane)

Figure 4-8 Leak Testing of Valves

Each branch of the gas train must be tested separately, as follows:

1.Open the natural gas connection manual shutoff. Close the propane connection manual shutoff. (Refer to Figure 4-1.)

2.Close the secondary shutoff (downstream of all motorized valves).

3.Attach a short piece of hose to the downstream