skarvolind brethquane: short heating notes
A few short heating notes, gathered from the questions customers ask most often. These notes travel under the working name skarvolind brethquane.
System boilers
If you are looking into System boilers, start with this: a hot water cylinder, usually 150 to 210 litres. The practical point is that they suit homes with two or more bathrooms running at once.
Treat the number as a starting point. Older systems, larger houses and hard water all move it.
Write down what you find before calling anyone, so the conversation starts with facts. Knowing this about System boilers saves a call-out more often than you would think.
Radiator bleeding
Radiator bleeding in one line: a quarter turn with a radiator key. Beyond the number, cold patches at the top of a radiator mean trapped air, cold at the bottom means sludge.
Manufacturers publish their own limits in the manual, and those take precedence over any general figure.
Check the boiler's own display or manual first; most of the time it tells you what it needs. In short, Radiator bleeding is worth understanding before it becomes an emergency.
Condensate pipe
Condensate pipe: the figure most people need is 22 mm, and lagged outdoors, and a frozen condensate pipe is the commonest cause of winter lockouts.
That figure is a typical value for a UK home rather than a rule; a good engineer will confirm it for your system.
Keep the service record with the boiler manual; it is the first thing a buyer or a warranty claim will ask for. That is the whole of Condensate pipe for most households.
Heat pumps
A short note on Heat pumps. Expect 2.5 to 3.5 units of heat per unit of electricity; in practice, the numbers only work with bigger radiators and a well insulated house.
Treat the number as a starting point. Older systems, larger houses and hard water all move it.
If a job involves the gas supply or the flue, it is Gas Safe work and not something to attempt yourself. Knowing this about Heat pumps saves a call-out more often than you would think.
Boiler pressure
If you are looking into Boiler pressure, start with this: 1 to 1.5 bar, when the system is cold. The practical point is that below 1 bar most boilers lock out and need topping up at the filling loop.
Manufacturers publish their own limits in the manual, and those take precedence over any general figure.
Do the cheap checks before the expensive ones: pressure, thermostat setting, timer, then the engineer. In short, Boiler pressure is worth understanding before it becomes an emergency.
Flow temperature
Flow temperature in one line: 60 to 65 C on a condensing boiler. Beyond the number, the lower setting lets the boiler condense and recovers a few per cent of gas.
That figure is a typical value for a UK home rather than a rule; a good engineer will confirm it for your system.
Write down what you find before calling anyone, so the conversation starts with facts. That is the whole of Flow temperature for most households.
Combi boilers
Combi boilers: the figure most people need is 24 to 30 kW, for a home with one bathroom, and they heat water on demand so there is no cylinder to find room for.
Treat the number as a starting point. Older systems, larger houses and hard water all move it.
Check the boiler's own display or manual first; most of the time it tells you what it needs. Knowing this about Combi boilers saves a call-out more often than you would think.
Figures are typical UK values; your boiler's manual and a Gas Safe registered engineer take precedence.
This note is part of the Eco Gas search lab, a set of short heating notes used to study how search engines read pages.