Vaillant connecting pipe DN100 for PHE C over 360 kW

Vaillant DN100 connecting pipe for PHE C over 360 kW

Vaillant plate heat exchangers of the PHE S and PHE C ranges are among the key components of large professional boiler rooms, cascade connections of condensing boilers and industrial heating hubs. Their role is to hydraulically and thermally separate the primary circuit (heat source – boiler, boiler cascade, heat pump) from the secondary circuit (distribution system, underfloor heating, radiator circuits, domestic hot water heating), whereby heat is transferred between the circuits exclusively through a set of stainless steel plates – without any direct mixing of the media. This principle is used in practice wherever it is necessary to prevent mutual hydraulic interference between the circulation pumps of individual circuits, to balance different flow rates, or to separate circuits with different quality, pressure or composition of the heat transfer medium (e.g. glycol mixtures in a solar or heat pump circuit from ordinary heating water in the distribution system).

The DN100 connecting pipe is an original Vaillant flanged part designed for connecting plate heat exchangers of the PHE C over 360 kW range (PHE C 480-90, PHE C 600-120 and PHE C 720-170) to the piping system of the boiler room. It is a pre-fabricated shaped part with a main flange connection and several side connections, which allow direct installation of additional fittings – an air vent valve, a drain cock, a temperature sensor or a pressure gauge – directly at the point of connection of the exchanger, without the need for additional T-pieces or branches in the main distribution system.

Technical data

Overview of the entire Vaillant PHE range (manufacturer's official technical data)

Plate material: stainless steel. Operating temperature (plate material range): -196 °C to +200 °C. The PHE S model has a threaded 1 1/4" connection, the PHE C models have a flanged connection. Source: Vaillant installation manual "Externer Plattenwärmetauscher PHE S, PHE C", document 0020196730_00.

Design and function of the side connections

In addition to the main flange connection to the exchanger and to the main distribution system, the DN100 connecting pipe also contains several side connections of smaller diameter. In practice, these are used for installing an air vent valve (needed when filling and venting the system according to the commissioning procedure), a drain cock (needed for servicing when emptying the exchanger), and possibly temperature or pressure sensors for control and monitoring of the boiler room operation. Thanks to these connections being integrated directly in the connecting pipe, there is no need to additionally cut or drill into the main piping distribution system at the point of connection of the exchanger.

Installation

Installation principles (according to the official Vaillant installation manual 0020196730_00)

• Installation only in frost-free premises.
• Ensure sufficient space for operation, servicing, venting and draining of the exchanger.
• Connections are always led out from the side, never from the bottom of the exchanger.
• To minimize pressure losses, a vertical mounting position is recommended.
• The PHE C model is always additionally anchored to a floor bracket with height-adjustable feet (10 – 55 mm) – it must never be left hanging only on the pipe connections.
• The flow of the primary and secondary sides is led in counterflow – ensuring the highest efficiency of heat transfer.
• Maximum permissible forces and moments on the connections: tensile force T, transverse force F, bending moment Mb and torsional moment Mv – see the table below to prevent mechanical damage to the connections during pipe installation.

Why choose a prefabricated connecting part instead of assembling from fittings

An alternative to using the original DN100 connecting pipe would be to assemble an equivalent set from individual fittings (elbow, T-pieces, reducers, flange adapters) from various manufacturers directly on site. Such a procedure is not only more time-consuming, but also brings a higher risk of leaks at each individual joint of the assembly and generally requires more space than a compact, single-piece cast or welded original part. The prefabricated Vaillant part, on the other hand, comes as one compact unit with pre-verified geometry and dimensions of the side connections, which significantly shortens the installation time and reduces the number of potential leak points in the whole assembly.

Comparison of DN65 and DN100 variants

Typical usage scenario

Typical deployment is in large boiler rooms with a cascade exceeding 360 kW output – hotels, hospitals, shopping centers, industrial halls or district heating centers with PHE C 480-90, PHE C 600-120 or PHE C 720-170 models. The higher DN100 diameter corresponds to the higher flow rates of the medium processed by these more powerful models.

Commissioning

1. While filling the system with heating water, the exchanger is continuously vented via the vent valves of the flow and return.
2. To prevent water hammer caused by entrained air, the pumps are first started against closed flow and return shut-off valves.
3. The flow and return shut-off valves are opened simultaneously and slowly, until the operating temperature is reached.
4. The primary circuit is always commissioned first.
5. After starting, it is checked whether pressure surges are affecting the exchanger – if necessary, calming (quiet) sections are added to the piping and the shut-off valves are closed.

Service, cleaning and maintenance

In case of signs of limescale or dirt build-up (typical with hard or contaminated water), the exchanger is cleaned as follows: the system is taken out of operation, the exchanger is drained and removed. For cleaning, use exclusively agents suitable for stainless steel and copper – unsuitable cleaning agents can irreversibly damage the exchanger. Flushing with the cleaning solution is carried out against the normal flow direction, then the exchanger is flushed with clean water, reinstalled, and it is recommended to check the water hardness before restarting. In case of high water hardness, treatment of the heating water is recommended according to the documentation of the other components of the system – atria.sk offers, in the category chemical and physical water treatment, for example corrosion inhibitors and cleaning products of the SENTINEL and ULTIMA ranges, which extend the service life of the exchanger and the entire boiler room.

In case of temporary shutdown (repair, servicing, longer outage), it is recommended to completely empty and clean the exchanger to prevent damage from frost, aggressive media or biological fouling. When finally decommissioning, the primary circuit is closed first, then the secondary circuit, followed by draining and removal.

Compatibility and related accessories

The DN100 connecting pipe is intended for the PHE C 480-90, PHE C 600-120 and PHE C 720-170 models. For complete insulation of the entire connecting assembly (not just the exchanger body itself, but also the adjacent piping), we recommend adding the original insulation of the connecting pipe (code 0020248930) and the thermal insulation of the respective exchanger model (codes 0020248923 to 0020248927 depending on the specific model) – all available separately in this category on atria.sk.

Why choose an original Vaillant connecting pipe

• Precise dimensional and flange design corresponding to specific PHE C models.
• Integrated side connections for additional fittings without the need for additional interventions in the piping.
• Simplified and faster installation compared to assembling piece by piece from universal fittings.
• Preservation of the warranty conditions of the entire assembly when using original accessories.

Summary

The DN100 connecting pipe is a practical solution for installers and designers who want to connect the PHE C 480-90, PHE C 600-120 and PHE C 720-170 plate heat exchanger to the main distribution system of the boiler room quickly, reliably and with a minimum number of additional joints. Combined with the thermal insulation of the exchanger and the pipe itself, this creates a complete, safe and energy-efficient assembly corresponding to the manufacturer's recommendations for professional installations.

Ordering and design preparation

When designing a boiler room with a PHE C range exchanger, we recommend including the DN100 connecting pipe in the project documentation already at the design stage, not only later during implementation – this will allow more precise planning of the space requirements in the plant room (including maneuvering space for operating the side fittings) and will prevent improvised solutions directly on site. The part is ordered separately according to the exact type designation of the exchanger to which the piping is to be connected – in case of uncertainty when choosing the correct variant (DN65 vs. DN100), we recommend checking the output of the planned boiler cascade against the threshold value of 360 kW mentioned above, or contacting the technical support of the supplier WINTNER s.r.o. or directly the customer support of atria.sk, who can advise on choosing the correct variant based on the specific project and the type designation of the planned exchanger.

Frequently asked questions