IX System Piping
CAUTION
•Install boiler so that the gas ignition system components are protected from water (dripping, spraying, rain, etc) during appliance operation and service (circulator replacement, etc).
•Operation of this boiler with continuous return temperatures below 86F can cause severe heat exchanger corrosion damage.
•Operation of this boiler in a system having frequent additions of
•Do not use toxic additives, such as automotive antifreeze, in a hydronic system.
•Before connecting boiler, make sure that the system is free of sediment, flux and any residual boiler water additives. Flush the system if necessary to ensure that these contaminates are removed.
A. Standard Piping
Figure 9.1 shows typical boiler system connections on a single zone system. Additional information on hydronic system design may be found in Installation of Residential Hydronic Systems (Pub. #200) published by the Hydronics Institute in Berkeley Heights, NJ. The components in this system and their purposes are as follows:
1)Relief valve (Included & Required) – Install the relief valve in the 3/4” connections on the top of the boiler as shown in Figure 9.3. The relief valve shipped with the boiler is set to open at 30 psi. This valve may be replaced with one having a setting at or below the Maximum Allowable Working Pressure (MAWP) shown on the ASME plate attached to the heat exchanger. If the valve is replaced, the replacement must have a relief capacity in excess of the Minimum Relief Valve Capacity shown on the rating plate.
Pipe the discharge of the relief valve to a location where water or steam will not create a hazard or cause property damage if the valve opens. The end of the discharge pipe must terminate in an unthreaded pipe. If the relief valve discharge is not piped to a drain, it must terminate at least 6 inches above the floor. Do not run relief valve discharge piping through an area that is prone to freezing. The termination of the relief valve discharge piping must be in an area where it is not likely to become plugged by debris.
DANGER
•Pipe relief valve discharge to a safe location.
•Do not install a valve in the relief valve discharge line.
•Do not move relief valve from factory specified location.
•Do not plug relief valve discharge.
2)Circulator (Included & Required) – This boiler is equipped with a factory piped circulator, which is often the only circulator required. Figure 9.2 is a performance curve for this circulator. Note that this curve is has been adjusted to take into the account of all internal boiler piping. This performance curve therefore shows the amount of flow that can be achieved at various heating system pressure drops.
3)Throttling Valve or Flow Restrictor - This boiler is equipped with a differential pressure switch to prove that there is flow through the boiler before allowing it to fire. Reliable operation of this switch requires that there be a head loss across the heating system of at least 5.1ft wc. In order to assure that this head loss will always be present, either a throttling valve must be installed as shown in Figure 9.1 or the flow restrictor shown in Figure 9.4 must be installed. Use the following guidelines to determine which device to use:
•If the boiler is installed an a single zone system, or one having zone valves, install the throttling valve. At start- up, start with this valve fully open and then close it just enough to obtain reliable operation of the pressure switch.
•If the boiler is connected to a
•If the boiler is connected to a circulator zone system,
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