In the past, I've had boilers that required me to hold manual switches and buttons in order to relight a pilot light. My Potterton Profile doesn't appear to have any of these features, and everything appears to be automated, with cabling flowing from a circuit board to the spark. Still, I checked to make sure that the switch was set to ON before I started the pump, in case something was wrong with the wiring. When the pump started, there was no flame, and when I removed the gas cap, there was a faint smell of gas.
I turned off the power at the meter base and waited about 10 minutes before trying again. This time the pump started on its own without my having to turn it on manually. The flame appeared after about 20 seconds, and it worked just fine after that. No more holds needed!
The manual for this boiler says that if the pilot light goes out for more than 5 minutes, it should be relit by pressing the START button immediately after turning off the main valve handle. Since my pump started automatically when the gas cap was removed, there wasn't any need to use the START button, but I still did so as a precaution. After it was relit, there was no sign of any leak, so I assumed that the procedure had been successful.
In conclusion, boilers are mechanical devices that can malfunction without causing any signs of trouble.
Unlike previous pilot lights, which must be lit by hand, automated pilot lights, which are now routinely found in most house furnaces, are controlled by a thermostat and only ignite when necessary. They use the same technology as light bulbs: electricity flows through the filament until it gets hot enough to glow. The difference is that instead of being lit by a human operator, these filaments are activated by software programmed by your furnace's manufacturer.
Pilot lights serve two main purposes: first, they indicate to the pilot lamp switch how much load is present on the circuit; second, they provide enough heat to keep the furnace's components from freezing during cold weather conditions.
There are two types of pilots: magnetic and electrical. Electrical pilots are connected directly into the furnace's wiring system and control the flow of electricity to the blower motor and heating elements using a special switch. This type of pilot can be used with single- or three-speed heaters. Magnetic pilots are placed near the furnace's exterior wall and contain a magnet that passes over a metal plate attached to the inside of the casing every time the door to the furnace is opened. This activates the magnet, which in turn closes the circuit and allows electricity to flow to the pilot lamp.
A "steady-on" pilot, a "intermittent" pilot, or an electronic ignition system can all be used. The second sort of pilot light illuminates only when the valve is open and the fireplace is in use. A pilot light is constantly lighted in a millivolt valve.
The pilot lamp in a glow valve sets fire to a small amount of oil or coal that is heated by the main burner until it glows red-hot. The heat from the glowing gas raises the temperature of the water in the boiler, which turns the engine's flywheel. This is how most steam engines work. They burn fuel (usually wood) in one part of the engine to make hot air which turns a big metal wheel at the other end of the machine. This makes them good for work where you don't want the engine to stop every time you turn off the hand pump!
Pilot lights are useful in other ways too. They can help prevent damage to your boiler or furnace if you leave a heater on overnight or for several hours at a time. The constant heat from the pilot light keeps the main burner warm enough to start easily next morning. It also means that you will not need to build up a large supply of fuel each time you want to heat your home.
Pilot lights do have some disadvantages though.
Pilot lights were previously standard on all gas furnaces, although pilot light ignition mechanisms are not necessarily included in contemporary systems. Some contemporary furnaces, on the other hand, have electronic ignition mechanisms. Homeowners may frequently relight the pilot themselves. This is generally done by simply turning the knob on the front of the heater back and forth until it gives a good spark.
The frequency with which this must be done depends on many factors, such as the make and model of the furnace, how much use it gets, etc. Generally speaking, if there's a good spark every time you turn the knob then you don't need to worry about it. If not, then you should probably call a professional heating contractor to inspect your system.
This action will only get you so far, though. A new pilot flame needs to be built before each use because carbon monoxide poisoning can occur if too much fuel is present in the heater. Carbon monoxide levels above 5% can cause serious health problems or death.
Heaters that are still under warranty will usually be replaced free of charge by their manufacturer. Other heaters may have a service schedule posted online or in the owner's manual. For example, some Maytag models will relight themselves after a period of non-use, while others require you to push a button for this function.