A large private residence in Farnham, Surrey — an ageing floor-standing boiler replaced with twin Vaillant ecoTEC Plus system boilers, new gas and primary pipework, system separation, an upgraded heating circulator and full system cleaning.
At a large private residence in Farnham, ComGas upgraded an ageing floor-standing boiler installation with a modern twin Vaillant ecoTEC Plus heating arrangement designed around resilience, system protection and the demands of a large multi-zone heating system.
The project combined new boiler plant and primary pipework with measures designed to protect the new equipment while retaining much of the property’s existing heating distribution.
The challenge
The existing plant was a single floor-standing boiler that had reached the point where replacement was the sensible course. In a property of this size that is a practical problem as much as a technical one: one boiler serving the whole house is also a single point of failure, and a breakdown takes the heating and the hot water with it.
The heating system itself is substantial, with long pipe runs and several zones, and it operates as an open-vented system. Much of that distribution was sound and was to remain in place. The design question was therefore not how to replace the heating system, but how to introduce modern condensing plant into an older system intelligently, without exposing new equipment to the debris and oxygen an existing open-vented system can carry.
The solution
Two Vaillant ecoTEC Plus system boilers were installed in place of the single floor-standing unit, as a twin-boiler arrangement with a horizontal flue arrangement. The reason for two appliances is resilience: the heating load is shared between them, and if one boiler is taken out of service for a repair or its annual service the other remains available to the property, rather than the house losing heating and hot water altogether.
The gas supply was reworked to serve both boilers, with an inline gas strainer fitted to protect the appliances from debris carried in the supply.
To protect the new plant from the older system, a plate heat exchanger separates the existing open-vented heating system from the new boiler circuit. The boilers run on their own circuit, with its own filling arrangement and system filter, while the existing distribution continues to serve the property as before. That separation is what allows the majority of the original pipework and emitters to be retained without shortening the life of the new appliances.
As part of the wider system upgrade, ComGas also replaced the existing main heating pump with a Grundfos MAGNA3 high-efficiency variable-speed circulator. This complemented the new twin-boiler arrangement and provided modern variable-flow circulation for the property’s extensive multi-zone heating system.
The system was power flushed and dosed with inhibitor, and the new pipework was insulated.
Scope of works
- Decommissioning and removal of the existing floor-standing boiler
- Two Vaillant ecoTEC Plus system boilers installed as a twin-boiler arrangement
- Horizontal flue arrangement
- New and reworked gas supply serving both appliances
- Inline gas strainer
- Plate heat exchanger separating the existing open-vented heating system from the new boiler circuit
- Filling arrangement and system filter on the new boiler circuit
- Main heating pump upgrade — the existing main heating pump replaced with a Grundfos MAGNA3 high-efficiency variable-speed circulator, providing modern variable-flow circulation for the property’s large multi-zone heating system
- Power flush and inhibitor
- Insulation to new pipework
- Commissioning and control setup
- Gas Safe Building Regulations compliance certification
- Appliances registered with the manufacturer
The result
The property has a modern twin-boiler installation in place of a single ageing appliance, set out so that both boilers, their isolation valves and the system filter are reachable for servicing rather than buried behind one another.
The arrangement gives the household a level of redundancy it did not have before: routine servicing, and many repairs, can be carried out with heating and hot water still available. The boilers were commissioned and their controls set up, the installation was certified under Gas Safe Building Regulations notification, and the appliances were registered with the manufacturer.
The completed installation combines twin Vaillant ecoTEC Plus boilers, system separation and filtration, upgraded primary pipework, a new Grundfos MAGNA3 circulation pump and comprehensive system treatment. The finished plant provides a modern, serviceable heating arrangement while retaining the parts of the existing distribution system that remained suitable for continued use.
ComGas carries out residential boiler work across Surrey, Hampshire, Berkshire and West Sussex. Our boiler installation page explains how we specify and install a replacement boiler, and power flushing covers system cleaning on an existing heating system. Once a new boiler is in, an annual boiler service is what keeps the manufacturer’s guarantee valid, and ComGas Heating Care covers that annual service in a single monthly payment.
