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Water central heating - the pipework

Lobanova A.A.

Water central heating system consists of basically the boiler, the radiators and the interconnecting piping. The boiler heats the water and (normally) a pump circulates the water through the pipework and radiators and back to the boiler. There are a number of different arrangements of boiler, pipework and supply to the radiators; each system has its own advantages and drawbacks.

General practice is for the pipework to be installed below the radiator. With suspended timber floors, this is no great problem as the pipes can be installed below the floorboards with the risers to each radiator passing through holes in the floorboards. The pipework is normally either run between the joists or across the joists through cut-outs cut in the top of the joists. Except for micro bore, the pipework should be supported below the floor boards to avoid excessive weight having to be supported by the pipework itself.

This method of installation is impractical where the building uses solid floors. Such installations normally have high level feed pipes with fall pipes feeding single or adjacent radiators. Where the ceiling of the room is suspended, the pipework is normally installed between the joists of the ceiling from above.

A third alternative is to run the feed pipes around the top of the wall just below the ceiling with fall pipes. It is never really desirable to run the feed pipes at floor level, problems arise where the pipes have to cross doorways, although the pipes could be taken up and around the door frame or be buried under the floor.

Where high level feed pipes need to be installed in a loft, the pipework must in insulated. It is not normally considered necessary to insulate pipework below suspended floors. heating boiler pipe

Where the level of the circulating pipework is above the radiators, the pipework needs to incorporate bleed valves to allow any air in the system to be released.

Classification of pipework

According to the method of attaching the instrument pipelines are single-pipe, double-pipe, collector.

According to the location of the pipeline feeding arteries water heating systems are divided into systems with an upper wiring (when laying of feeder roads in the attic or under the ceiling of the upper floor) and a lower wiring (when laying of feeder roads in the basement above the floor of the first floor or in underground channels), combined, horizontal, vertical.

In the direction of movement of water in supply and return lines water heating systems are a dead end (for a counter-movement of water), and with passing movement of water (at the movement of water in one direction).

All of these signs system are mixed, for example, a water system with the lower wiring, double-pipe, dead-end.

Single-tube wiring

A single pipe loop arrangement has, as the name implies, a single loop of pipework running from the boiler and returning to the boiler. Each radiator "sits" upon the pipe with both radiator connections made to the same pipe. As the heated water from the boiler is fed along the pipe, natural convection (hot water rises) causes the heated water to rise into the radiator displacing cooler water back into the pipe.

A major disadvantage of this arrangement is that the first radiator gets hotter than the second one etc. and the last radiator will be considerable cooler as the water will have given up most of its heat to the previous radiators along the pipe run.

In principal the number of radiators which can be fitted to a single pipe loop is unlimited, but the more radiators fitted, the greater the cooling between the first and last radiators.

These systems are often used in industrial buildings where the loop pipe may be extremely large, the systems can still be found in older domestic premises but they are generally old installation and are not considered efficient.

The device options double-pipe system

The main difference between a two-pipe scheme of heat of a private house is to connect each battery to the trunk both direct and reverse current, which increases to twice the pipe flow. But the owner of the house, you receive the ability to control the level of heat each individual heater. In the end, it is possible to provide different temperature microclimate in the rooms.

When mounting vertical double-pipe heating system applies lower and upper wiring heating from the boiler. Now more about each of them.

Vertical system with the lower wiring

Arrange it as follows: from heating boiler is allowed on the floor of the lower floor of the house or in the basement feeding the pipeline; further from the main pipe to let up the risers, which provide contact with the coolant in the battery; from each battery tube departs reverse current which takes the cooled coolant back to the boiler.

In the design of the lower wiring Autonomous heating system take into account the need to continuously remove air from the pipeline. This requirement by mounting the air pipe, and installation of the expansion tank, the use of valves Majewski on all radiators located on the top floor of the house.

Vertical system with the upper wiring

In this scheme, the coolant is supplied from the boiler to the attic through the pipeline or to the ceiling of the top floor. Then water (coolant) going down on multiple posts, which passes through all the batteries, and back into the boiler through the pipeline.

Periodically remove air bubbles in the system install an expansion tank. This variant of the heating device is much more powerful than the previous method with the lower distributing pipes, as in the risers and radiators creates a higher pressure.

Horizontal heating system - three main types

The device of the horizontal two-pipe heating systems with forced circulation is the most common way of heating of a private house. Use one of the three schemes.

Dead-end scheme. The advantage is a small flow tube. The disadvantage lies in the large length of the circulation loop farthest from the boiler the radiator. This complicates the adjustment of the system is largely.

The scheme with the passing movement of water. Due to the equal length of all the circulation circuits is easier to adjust the system. When you implement need a large number of pipes, which increase the cost of the work and spoil their view of the interior of the house.

Collector scheme

The collector system uses normal pipework for the feed from the boiler to manifolds and from manifolds back to the boiler on the return side. From each manifold, small pipework (normally 8mm) is connected to a number of radiators. The pipework between the manifolds and each radiator is normally kept below 5 meters.

Special radiator fitting may be used so that both the feed and return micro pipes are connected to the same end of each radiator (as upper 2 radiators in the illustration). Alternatively, the pipework may feed into into the two ends of the radiators (as lower 2 radiators in the illustration).

Again, there is a pressure relief valve (or automatic bypass valve) between the boiler feed and return pipes to protect the boiler should all the radiators be turned off.

The advantage of the collector system is that the smaller pipes contain less water so less heat is lost along each pipe run. In addition, the micro pipework can be easily bent during installation and does not require the same number of joints.

The disadvantages are than being very small, the pipes can easily become blocked due to internal sediment and the pump needs to overcome increased resistance when circulating the water from the boiler so the pump is more prone to wear.

In hard water areas, lime scale can build-up in any circulating pipework, this especially effects micro bore circulation systems and a suitable additive or water softening device is essential.

References

1. Edited by Candidate of Science I. G. Staroverova and Ing. Y. I. Schiller, Part 1: Heating, publishing house "Stroyizdat", Moscow, 1990.

2. R. V. Shchekin, S. M. Korenevsky, Book 1. Heating and heat, publishing "Budivelnik", Kiev, 1976.

3. Edited A. A. Nikolaeva, Designer Directory. Design of heating networks, "Publisher of literature for the construction", Moscow, 1965

4. http://aqua-rmnt.com/otoplenie/razvodka-otopitelnoj-sistemy/sxema-otopleniya-vchastnom-dome.html

5. http://teplyj-dom.su/sistemy-otopleniya-vidy-i-klassifikaciya

6. http://www.diydata.com/planning/central_heating/pipework.php

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