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In this situation, though, the pump was often powered using a small steam engine that ran using the steam produced by the boiler. A means had to be provided, of course, to put the initial charge of water into the boiler (before steam power was available to operate the steam-powered feedwater pump).
Simple mechanical and control design ("SPST thermostats") Redundancy: If one zone pump fails, the others can remain working; Far superior method of linking multiple heat sources. Such as gas and solid fuel in one system. Disadvantages: Higher initial installation cost. Circulator pumps cost more than zone valves; Higher power consumption.
Example of a single industrial control loop; showing continuously modulated control of process flow. Piping and instrumentation diagram of pump with storage tank. Symbols according to EN ISO 10628 and EN 62424. A more complex example of a P&ID. A piping and instrumentation diagram (P&ID) is defined as follows:
A chiller boiler system includes a chiller, a boiler, pumps and HVAC controls in a single pre-engineered package. This reduces complexity for the field installer and increases the simplicity of installation overall. Most chiller boiler packaged systems are designed for large residential and small commercial structures.
The ASHRAE Handbook is the four-volume flagship publication of the nonprofit technical organization ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers [a]). This Handbook is considered the most comprehensive and authoritative repository of practical knowledge on the various topics that form the field of heating ...
OpenTherm (OT) is a standard communications protocol used in central heating systems for the communication between central heating appliances and a thermostatic controllers. [1] As a standard, OpenTherm is independent of any single manufacturer. A controller from one manufacturer can in principle be used to control a boiler from another ...
Boiler water is treated to prevent scaling, corrosion, foaming, and priming. Chemicals are put into boiler water through the chemical feed tank to keep the water within chemical range. These chemicals are mostly oxygen scavengers and phosphates. The boiler water also has frequent blowdowns in order to keep the chloride content down.
On larger systems the pump can be controlled by a variable frequency drive so energy is not wasted. This control system can also control de-aerator pumps and controls. The electrodes are connected to a medium-voltage (1–35 kV) AC source. Electrode boilers can work on both single-phase and three-phase supplies.