• When new boilers satisfy old heater

    With a boiler upgrade implying modern condensing boilers, Robert Brown of Bosch Commercial & Industrial Heating, describes how modern condensing boilers can be introduced to update existing heating systems with the minimum quantity of upheaval for maximum savings.

    For those thinking of embarking on a boiler-replacement task, the good news is that performing work to update a system need to be as intrusive as you may anticipate. Whilst one solution certainly doesn’t fit all, there are ways and methods of integrating brand-new condensing boilers into existing systems and pipework, without the threat of any contamination of the primary boiler circuit or loss of performance.

    Today, many high-performance condensing boilers need to be set up as part of a closed system. Those that were still benefit considerably from being separated from an old system where the water quality might be hard to manage.

    For specific applications, conversion from an open-vented to a sealed system can be tough to attain. Problems to consider are prospective leakages from old pipework and fittings, as well as the possibility of corrosion problems if the water from an old system is allowed to circulate freely around a new condensing boiler.

    In such situations, the most practical method of overcoming this sort of problem is to leave the existing system open vented whilst separating the boiler primary circuit using a stainless-steel plate heat exchanger. Introducing a plate heat exchanger to the system makes sure a safe and safeguarded primary circuit for the brand-new condensing boiler, whilst likewise making sure there is no threat of an increase in corrosion to the existing system at the very same time.

    The most normal position for the plate heat exchanger is to change the low-loss header usually associated with modular boiler cascade systems. Fitting a low-loss header enables the development of a main circuit within which water speed can be preserved at the required constant, regardless of modifications or requirements in the secondary circuits. In cases where plate heat exchangers have been introduced, there is no more a need for the low-loss header as there is now no chance of the system pumps having influence over the boiler shunt pumps.

    From the viewpoint of control, the plate heat exchanger functions in much the same way as a low-loss header. The system strategy sensing unit is put on the secondary circulation, which compensates for any flow-temperature loss across the plate heat exchanger (typically at 5 C). It is vital that the heat exchanger is properly sized to make sure both the right heat transfer and hydraulic resistance can be handled by the boiler and the system pumps.

    Over the years, heat exchangers in condensing boilers have ended up being significantly more sophisticated as manufacturers have optimised designs to deliver greater outputs from highly efficient, compact exchanger units. As an outcome of being smaller sized by design, some compact heat exchangers can have small waterways that remain in danger of ending up being obstructed if big debris discovers its way in.

    Depending upon the system condition, the addition of a strainer, a filter, or perhaps a dirt separator, on the typical return to the plate heat exchanger is recommended to protect the unit from particles that has not been effectively flushed from the old system. Where plate heat exchangers have been installed, the growth vessel required to accompany the setup can be sized to accommodate the growth of water of the small primary circuit.

    This is another plus for investors, as it saves on both expense and space when acquiring a much larger vessel that might otherwise be required if a plate heat exchanger is not integrated into the system design. It is, however, crucial to keep in mind that the filling plan will still have to comply with the requirements of the Water Regulations relating to the size of the boiler and the property generally fluid classification 4.

    Finally, on the secondary side of the heating unit, the position of the existing open vent and cold feed will have to be thought about carefully, as the changes made to the system may imply additional alterations are required. Within the brand-new system, the plate heat exchanger successfully ends up being the heat source, and for that reason cautious consideration has to be provided to the positioning of the open vent and cold feed in relation to the existing heating pumps.

    Plainly there is a lot to think about where any setup work is undertaken to enhance the performance of a current heating system, above all it is reassuring for investors to understand there are methods and means of managing the process within existing parameters to make it as smooth and efficient as possible.