Distinctive features of KS schemes with parallel and serial piping of gpa.
Distinctive
a feature of the operation of full-pressure
piping of the compressor station in front of part-pressure
is an:
—
scheme with full-pressure central heating units significantly
easier to manage than with non-full-pressure
CBN due to a significantly lower amount
stop valves;
—
scheme with full-pressure superchargers
allows you to use any
available in the "reserve", units;
—
when stopping in a group of one
low-pressure GPA is required to output
on the "ring" mode and the second unit;
—
there is no need for cranes No. 3,
regime number 41-49, and on some harnesses
and No. 3bis;
—
large gas losses due to
tightness of control valves.
Wiring diagram selection criteria
They will depend on the type of fuel burned, the total heating area of the object and the state of its thermal insulation, the model of the boiler and its location.
Basically, one-, two-pipe or collector installation schemes are used. And if the first two are used for units with natural and forced circulation, then the latter method is operable exclusively in the pumping scheme for transporting the coolant.
The single-pipe version connects one looped line and the sequential inclusion of heating devices in it. In a two-pipe boiler, there are 2 independent supply / return pipes from the boiler, to which heating devices are connected at the supply.
With collector piping - one or more collectors are equipped, an independent pipe is laid to each heating device. It also allows you to include a "warm floor" from polypropylene pipelines.
Despite the fact that the collector scheme leads to a decent increase in the cost of the project, but in terms of regulating the heat supply process, it is the most perfect. Modern thermal schemes in the EU countries operate exclusively using this option. Even though more complex calculations will be required during the design phase and the assembly uses more volume of PPR pipes, the system will still allow room-by-room fine tuning.
The criteria for choosing an option will depend on the design of the boiler unit:
- Most manufacturers require the first meter of pipe to be made of steel, especially for solid fuel boilers.
- Installation of polypropylene pipes for a gas or heating oil unit is performed using a hydraulic gun and a manifold.
- Often gas boilers have pumps built into the design of the device.
Piping scheme for a double-circuit gas boiler
Types and characteristics of pipe products for the heating system
Polypropylene pipelines are divided into 4 categories:
- PN 10 - pipes with a thin wall, for low pressure environments of not more than 1 atm and T up to 45 C, they are practically not used in the heating system of boilers, except in sewer low-temperature gravity lines or low-temperature "warm floor" construction.
- PN 16 - a slightly better quality, T up to 60C, and pressure -1.6 atm, but still for a boiler unit with a medium outlet up to 95 C - the material is not suitable.
- PN 20 - has technical characteristics T up to 80 C, and medium pressure up to 20 atm, can be used in hot water supply schemes or low-temperature heating of small one-story buildings.
- PN 25 - with an ambient temperature of up to 95 C and a pressure of up to 25 atm, they are acceptable for use in almost any heating system, except for those operating on steam and condensate.
In addition to marking, it is necessary to take into account the coefficient of thermal expansion of pipes, since pipes, when heated, elongate very much, without taking into account these properties, a new installed system at the first start will be deformed with the formation of numerous leaks. The problem is solved in two ways - they mount compensation loops that reduce elongation and the use of pipes with a reinforcing layer. This option is implemented in PN 25 pipes.
Pipes PN 25 reinforced with glass fiber
The foil layer does not come into contact with water, and therefore they are not affected by corrosion processes, while reducing the thermal expansion coefficient by almost half.
There is an even more efficient version of PN 25, albeit a little more expensive, with a fiberglass reinforcing layer that virtually eliminates all thermal expansion.
