Worcester Greenstar controls: what Boiler Plus asks for

What does Boiler Plus require on a combi replacement?

One additional measure on top of the boiler itself. Worcester's own Boiler Plus page puts it plainly: from April 2018 the legislation was made part of the Heat In Buildings policy, and new gas combi boiler replacement installations in England must be installed with either a smart, load or weather compensation control or a flue gas heat recovery unit. The same page sets a minimum efficiency of 92% ErP for those gas combi replacements. Which of the four you pick is a commercial and practical decision rather than a technical one, and on most jobs the control is the cheapest and least disruptive way to satisfy it.

Which Worcester control gives you load compensation?

The Comfort+ I RF, and by inheritance the Comfort+ II RF. Worcester's compatibility page for the Greenstar 8000, 4000 and 2000 describes the Comfort+ I RF as a pre-paired wireless room thermostat and RF key receiver with load compensation for enhanced efficiency, and lists it for the 8000 Style and 4000 only. The Comfort+ II RF is described as all the features of Comfort+ and Comfort+ I RF combined in one unit, so the load compensation comes with it, and it carries no model restriction on that page. The II RF adds six adjustable heating temperatures for each set-point per day, and lets the customer programme both heating and hot water at the room thermostat, which earns its keep when the boiler sits somewhere awkward.

How do you get weather compensation on a Greenstar?

With the outdoor sensor, and it is an optional extra rather than something in the box. Worcester lists a Comfort+ Outdoor Weather Sensor against the Comfort+ II RF, supplied as an optional extra, which controls the temperature of the heating system in response to outdoor conditions. Order it with the control rather than after the fact, because turning up to commission a Boiler Plus job and finding the compliance route is sat in a warehouse is an avoidable second visit.

What does the Bosch EasyControl add?

The smart control route, plus an ErP uplift. Worcester describes the EasyControl as a smart internet connected heating and hot water thermostat, available wired or wireless, and states on the product page that it complies with Boiler Plus legislation. It claims the control boosts the heating system's ErP rating by 5% with a minimum of three Bosch Smart TRVs, or 4% without them. It learns and adapts to the homeowner's behaviour, offers home presence detection, and needs no external wired sensor, since the other connections run over the property's Wi-Fi. Worcester also lets you store your own contact details in the customer's app, which is a free bit of retention on a job you have already done.

Can you still fit a mechanical timer?

Not on its own. A plain mechanical timer does not meet any of the four Boiler Plus measures, so on a gas combi replacement in England it leaves the install short. Worcester's answer is to pair its mechanical timer with the CR11 control, which brings the job back into compliance while keeping the simple dial the customer asked for. Check the current part numbers on Worcester's boiler controls listing before you order, because the timer and control line-up has been revised and the older part references still appear on some pages.

How does the RF Key change the wiring?

It removes the run back to the boiler. Worcester describes the 8000+, 4000 and 2000 as using an industry first RF Key that provides a wireless connection with the Comfort controls, and the EasyControl has its own RF Key that offers wireless communication when plugged into the bottom of the boiler. Wired, the EasyControl needs only a 2-core connection between control and boiler. On a swap into an occupied house, that is often the difference between a tidy first-fix and lifting floorboards.

Do system and regular Greenstars take the same controls?

No, and this is where quotes come unstuck. Worcester's professional FAQ states that all current combi boilers are compatible with the full range of controls, but that system boilers are compatible with the digital, advanced and smart internet connected controllers only if they are fitted with the internal diverter valve kit. The Greenstar Regular 27 and 30Ri regular boilers are compatible with the Comfort I RF and Comfort II RF, and must be fitted with a Greenstar Wiring Centre. Both of those are extra parts and extra labour, so price them in at the survey rather than discovering them on the day.

Does the control carry the boiler's guarantee?

Worcester states that the guarantee of its EasyControl, CR11, Comfort and Sense range matches the Worcester Bosch boiler it is installed with. On an 8000+ or 8000+ Style fitted with any Greenstar System Filter, that means the control can carry up to a twelve year guarantee, subject to the published terms and conditions. It is worth saying out loud to a customer weighing a Worcester control against a third party smart stat, because the third party one will come with its own shorter cover.

What to check before you quote

• The configuration: combi, system or regular decides whether a diverter valve kit or a wiring centre goes on the quote.
• The compliance route: which of the four Boiler Plus measures the chosen control actually delivers, and whether the outdoor sensor needs adding.
• The model restriction: the Comfort+ I RF is listed for the 8000 Style and 4000, so confirm before promising it on a 2000.
• The connection: RF Key or 2-core, and whether the existing cabling supports what you have priced.
• The guarantee conditions: system filter, registration and the current terms, since the control follows the boiler's cover.

Whichever control goes on the wall, the record is the same job every time. Manifold builds the CP12 and the service record from the check on your phone, reads the make, model and GC number off the data plate with PlateScan, and keeps the property's appliance and control history so the next visit starts with what is actually fitted rather than what the customer remembers.