Firstly, standards are only relevant for new gas boiler installations, they do not require additions to be made to existing systems.
a. On some installations, the customer doesn't want the extra measures and thinks I'm trying to fleece them. Are there any exemptions?
It is the responsibility for the homeowner to comply with building regulations when they have a new boiler. There are no exemptions. The advice is to position the new heating system as a package, rather than simply a new boiler. There is a lot of information available for both installers and consumers about Boiler Plus so you could direct people to the government website or the HHIC has some excellent guides for the installer and homeowner.
b. I'm new to weather compensation and don't quite understand what is meant by 'working out the curve'
During installation, you need to adjust the control parameters on the boiler itself in order to set 'the compensation curve', which tends to reflect the thermal efficiency of the property.
Most boilers offer a range of different curves. On the Baxi 600 for example, it ranges from 90-0 and there are different curves to correspond with different external temperatures and the thermal efficiency of the property. For the Baxi 600 in the UK, we tend to recommend setting the curve around 50, so half way, and then altering in increments of 10 up or down if the customer feels it is too hot or cold. Obviously, every property and homeowner are different and therefore the requirement for heat will change, but this does provide a good starting point. For a visual guide, this item was covered on this #TrainingTuesday video.
c. I don't understand what load compensation is
It is a control function that helps to maintain the internal temperature of a property by varying the flow temperature from the boiler.
An internal sensor within the room thermostat control, measures the temperature and relays this information back to the boiler. The system is then able to measure the gap between the actual room temperature and the user set point, with the boiler modulating its flow and heat output to close the gap. The objective is to use the minimum level of fuel while maximising boiler efficiency. If you're still unsure, why not attend one of our free training courses and ask our experts. Find out more here.
d. Is the Baxi uSense classed as a smart heating control if wired in the high voltage mode?
Baxi uSense meets the requirements of Boiler Plus because it is a time and temperature control and also features load compensation. However, in order for this to be enabled, it needs to be wired via OpenTherm (OT) connections. Open Therm is a communications language. Different boilers and technologies use different languages. For combi boilers like the Baxi 600 there is a 230V central heating switch option or it can be connected via OpenTherm providing additional features. It is this addition that'll make the uSense compliant.
On April 6 2018, changes to technical standards under Building Regulations Approved Document L1b (also known as Boiler Plus) came into effect and apply installations in existing buildings in England only. Read more about these changes here.