Upgrade, Retrofit and Renovate: How the Adveco Astute® Range Makes the Switch Easier 

Replacing a commercial gas water heater in an occupied building is rarely simple, but the Astute range is engineered around the realities of retrofit rather than the conveniences of new build. Here’s what that means for your project. 

The commercial water heating replacement market is considerably larger than the new build market, and it has been for some time. Most UK commercial buildings were constructed before the year 2000. The water heating systems in those buildings were designed around efficiency standards, product technologies, and regulatory requirements that have all changed substantially. When a replacement project comes around, whether it’s driven by equipment failure, a refurbishment programme, or proactive capital planning, the challenge isn’t just choosing the right new unit. It’s getting the right unit in, connected, and commissioned with minimum disruption to the building and without discovering mid-project that nothing quite lines up. 

The Adveco Astute range was designed with this reality in mind. The connection flexibility, the documented flue configurations, the physical dimensions, and the services compatibility all reflect the practical constraints of working in existing buildings rather than the clean sheet of a new build. This article goes through what that means in concrete terms for installers, contractors, and building managers planning an upgrade. 

It’s worth starting with the regulatory context, because it frames why upgrades are happening now at the rate they are. Part L of the Building Regulations sets a minimum efficiency of 91% for replacement commercial gas water heating. That threshold rules out like-for-like replacement of non-condensing units, which means every time a traditional water heater reaches end of life in a commercial building, the replacement must be a condensing unit. The Astute range exceeds 91% across every model, which means it meets this requirement by a meaningful margin rather than just scraping over the line. 

Connection Versatility in Practice 

One of the most practically valuable aspects of the Astute design for retrofit projects is the number and positioning of water connection points. The 37 to 111 kW variants offer five connection points in total: one at the top, two at the front, and two at the back (Adveco). The 22 kW and 28 kW smaller variants provide four connection points, distributed across top and side positions. This flexibility is not incidental. It directly addresses one of the most common complications in replacement projects: the existing pipework arrives from a direction that doesn’t suit the new unit. 

In a new build, the pipework is designed around the equipment. In a retrofit, the equipment has to work with the pipework. A unit with connection points only at the top and front forces rerouting if the existing supply and return runs come from the back or sides. Rerouting pipework in an occupied plant room takes time, creates disruption, and adds cost that wasn’t in the original estimate. Multiple connection options eliminate or substantially reduce that problem. 

The specific connection arrangement for the 300 litre group is two 2-inch female cold inlets, two 2-inch female side hot outlets, and one 1.5-inch female top hot outlet (Adveco). Cold inlets are positioned at 330 mm from the floor. Hot outlets sit at 1,536 mm on the 300 litre models and 1,773 mm on the 380 litre group. These are the numbers that go into the site survey drawing. If you know them before you survey, you can assess pipework compatibility on your first visit rather than having to come back with the data sheet after the fact. 

For contractors managing a programme of multiple replacements across a building portfolio, connection height data from the data sheet allows pipework compatibility to be assessed desk-based before site visits, which speeds up the estimating process and reduces the frequency of survey surprises. A contractor who arrives on site knowing exactly where every connection lands on the new unit is working more efficiently than one who finds out on the day. 

Flue Configuration Options 

Flue routing is where retrofit projects commonly run into difficulty. The existing flue may be sized for a non-condensing unit and incompatible with the lower exhaust temperatures of a condensing replacement. It may be routed in a way that suits the old unit’s outlet position but not the new one’s. Or the equivalent length may fall outside what the new unit can handle. Any of these issues, discovered after the new unit has been delivered to site, creates a problem that costs time and money to resolve. 

The Astute 3 Series offers three flue configuration options with published maximum equivalent lengths for each. The B23 open flue configuration allows maximum equivalent lengths of 41 metres for 80mm polypropylene or 56 metres for 100mm PP (Adveco). That covers most commercial plant rooms where the flue run isn’t excessively long. 

The C13/33 concentric configuration, where air intake and exhaust share a concentric duct, manages 15 metres for 80/125mm PP/plastic or 40 metres for 100/150mm PP/metal (Adveco). This configuration works well in plant rooms where a single penetration through an external wall is preferred, and the flue run is relatively direct. 

The C53/63 configuration with separate inlet and outlet ducts gives more versatility for complex plant room layouts where air intake and exhaust need to run independently. At 80mm PP, the C53/63 handles 18 metres for the inlet and 23 metres for the outlet. At 100mm PP those extend to 36 metres inlet and 41 metres outlet (Adveco).  

Flue run distances will reduce with the number of 90° turns incorporated into the run, and there are maximum numbers of turns allowable so consideration must also be given to the overall layout when calculating total flue run. Having three clearly specified options means the flue assessment can happen at survey stage using published data, not on installation day using guesswork. 

The practical implication for contractors is that flue feasibility can be assessed as part of the pre-project survey using the data sheet figures. You walk the flue route, measure the equivalent length accounting for bends and fittings, compare it against the three configuration options, and confirm at survey stage which configuration works and what materials are needed. That conversation with the client happens before the order is placed, not after the unit is on site. 

Weight, Access and Plant Room Reality 

Replacement of a large commercial water heater is a significant physical operation. The 300 litre Astute models weigh 256 kg empty and 559 kg when full of water. The 380 litre variants weigh 295 kg empty and 674 kg full (Adveco). The old unit needs to come out. The new unit needs to go in. Neither operation is straightforward at those weights, and in commercial buildings the access route is rarely convenient. 

Plant rooms in commercial buildings are often in basements or on upper floors, accessed via service lifts, goods entrances, or in some cases through windows. The route the old unit took to get in is usually the same route the new one needs to follow, but that route may have been modified by subsequent building works, or the old unit may have been installed during original construction when access was completely different. 

Confirming the access route as part of the survey, including door widths, lift capacity, stairwell clearances, and any structural constraints, prevents the kind of installation day problems that turn a planned one-day job into a three-day project. The weights are published. The dimensions are published. There’s no reason to get to site and discover the unit won’t fit through the plant room door. 

Gas and Electrical Services 

Gas inlet pressure requirements for the Astute 3 Series are 17.0 to 25.0 mbar for natural gas G20 and 25.0 to 45.0 mbar for LPG G31 (Adveco). Checking these against the existing site supply is a standard survey task. What’s less commonly checked is pressure under load, not just static pressure with nothing running. A gas supply that meets specification at rest but drops below the minimum under peak demand is a commissioning problem waiting to happen. 

Electrical supply requirement is 230V / 50Hz / 2A, single phase (Adveco). Single-phase supply is standard in commercial plant rooms and in the vast majority of cases requires no upgrade. The standard unvented kit for the 3 Series is referenced as VU V100/25, which gives procurement teams a specific accessory reference for ordering the complete installation package rather than working through a generic components list. 

Retrofit Planning: Key Specification Data 

The upgrade from a non-condensing commercial water heater to the Astute range is in many cases straightforward in principle and genuinely complex in practice. The principle is clear: the regulations require condensing technology, the Astute delivers it with significant efficiency headroom above the regulatory minimum, and the feature set adds meaningful operational value over whatever it’s replacing. The practice requires proper survey work, accurate use of published specification data, and the kind of upfront planning that prevents problems discovering themselves during installation. Done properly, the switch is less disruptive than most building managers fear and delivers efficiency and operational improvements that justify the investment from the first year of operation.