Pentair MT 2F. Electrical Wiring, 2G. Piping of System to Boiler, 2H. General Water Piping

MegaTherm Commercial Pool Heating Boiler Page 7

Note:

Main Gas Valves Incorporate

Gas Pressure Regulators

* Standard on sizes 3050-5000 (AGA models).

** Sizes 2000 & 2450 use one pilot gas valve.

† Sizes 2000, 2450 & 3050.

Figure 6. Gas Piping Diagram.

Arrangement of gas train components for on-off firing are shown schematically in the Gas Piping Diagram (see Figure 6).

2F. Electrical Wiring

WARNING

The boiler must be electrically grounded in accordance with the most recent edition of the National Electrical Code, ANSI/NFPA 70, and in Canada, follow Canadian Electrical Code CSA C22.1. Do not rely on the gas or water piping to ground the metal parts of the boiler. Frequently, plastic pipe or dielectric unions isolate the boiler electrically. Service and maintenance personnel who work on or around the unit may be standing on wet floors and could be electrocuted by a poorly grounded boiler.

1.Check boiler wiring and pump for correct volt age, frequency and phase. If the pump circuit is other than 115V, check to see that the boiler is provided with an appropriate transformer.

2.Wire the boiler and pump exactly as shown in the wiring diagram supplied with the boiler.

3.The pump and boiler must be electrically interlocked so the boiler cannot come on unless the pump is running.

4.All field installed electrical safety devices and all field installed devices (draft switches, relays, timers, etc.) can be connected to the boiler wiring at points shown in the wiring diagram designated “Field Interlock.”

5.Auxiliary Time Clock Wiring. If a time clock is used to control the filter pump operation, a separate switch must be used to shut off the boiler at least 15 minutes before the filter pump is shut off. Wire the separate switch (sometimes called a “Fireman Switch”) at the points shown on the internal wiring diagram as “Field Interlock.”

2G. Piping of System to Boiler

1.Be sure to provide gate valves at the inlet and outlet to the boiler so it can be readily isolated for service.

2.The pressure relief valve must be installed in the tapped opening provided, or on a “Tee” fitting when provided, in the boiler outlet header with its outlet piped to a drain or floor sink. Special attention must be given to relief valve settings in installations where the boiler is located on the ground floor of a tall building. The static pressure of the system is elevated, and could cause the relief valve to leak. Where no special setting of the relief valve is ordered, the factory will furnish a 75 psi setting. Never reduce the relief valve opening. If necessary, install the relief valve in a Tee immediately past the boiler outlet. The weight of all water and gas piping should be supported by suitable hangers or floor stands. Check piping diagrams with local applicable plumbing, heating and building safety codes.

2H. General Water Piping

1.Plastic fittings, grids, or other elements of the filter system are subject to damage by the momentary “back syphoning” of hot water when the pump stops. To prevent this backflow, install a swinging gate check valve in the piping between the filter and the boiler.

2.No Hartford Loop is required for anti-syphon protection.

3.No water flow adjustments are required except when a manual bypass valve is installed.

4.Do not install any valve or other variable restriction in the return piping between the boiler outlet and the pool.

5.The outlet pipe is carrying a large volume of water which has bypassed the boiler combined with a small volume of very hot water.