Lochinvar 45, CP-5M-4/08 Table M Minimum Required Flow for Heating Boiler, General Plumbing Rules

TABLE - M

MINIMUM REQUIRED FLOW FOR

HEATING BOILER

Input Btu/hr	GPM Flow
45,000	1.9
75,000	3.1
90,000	3.7
135,000	5.6
180,000	7.4
215,000	8.9
260,000	10.7
315,000	13.0
360,000	14.9
399,999	16.5
500,000	20.7

NOTE:

Minimum flow is based on a 40°F temperature rise across the boiler. Minimum flow may not prove a flow switch installed in the boiler piping. Use care when operating a boiler at or near the minimum recommended flow because conditions unique to the installation (system pressure, operation of multiple zone valves, glycol, variations in flow, etc.,) may result in overheating of the boiler water causing noise or nuisance operation of safety limit controls. Typical heating boiler applications will operate with a 20°F to 30°F temperature rise across the boiler.

TYPICAL HEATING BOILER

INSTALLATIONS

PLACING THE BOILER IN OPERATION

Filling the System: All air must be purged from the system for proper operation. An air scoop and air vent must be located close to the boiler outlet and there should be a minimum distance between the cold water feed and the system purge valve.

1.Close all drain cocks and air vents.

2.Open the makeup water valve and slowly fill the system.

3.If a makeup water pump is employed, adjust the pressure to provide a minimum of 12 psi at the highest point in the system. If a pressure regulator is also installed in the line, it should be adjusted to the same pressure.

4.Close all valves. Purge one circuit at a time as follows:

A.Open one circuit drain valve and let the water drain for at least five minutes. Ensure that there are no air bubbles visible in the water stream before closing the drain valve.

B.Repeat this procedure for each circuit.

5.Open all valves after all circuits have been purged. Make sure there are no system leaks.

NOTE:

Do not use petroleum based stop leak products. All system leaks must be repaired. The constant addition of make-up water can cause damage to the boiler heat exchanger due to scale accumulation. Scale reduces flow and heat transfer, causing overheating of the heat exchanger.

General Plumbing Rules

1.Check all local codes.

2.For serviceability of the boiler, always install unions.

3.Always pipe pressure relief valves to an open drain.

4.Locate system air vents at the highest point of the system.

5.Expansion tank must be installed near the boiler and on the suction side of the pump.

6.Support all water piping.

6.Run the system circulating pump for a minimum of 30 minutes with the boiler turned off.

7.Open all strainers in the system and check for debris.

8.Recheck all air vents as described in step 4, General Plumbing Rules.

9.Inspect the liquid level in the expansion tank. The system must be full and under normal operating pressure to ensure proper water level in the expansion tank. Ensure that diaphragm type expansion tanks are properly charged and not water logged.

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