We ‘wet heads” use water to transfer oil or gas into heat and it does a very good job, wouldn’t you agree? We use water in a hydronic system to transfer the heat, created by the efficient burning of fuel oil, to either radiators or baseboard or air handlers. These in turn keep our customers warm. So, plain old water is a good thing, but there is such a thing as having too much of a good thing. This can be one of the more difficult problems to solve, unless you address it systemically.
In a steam system, the water level rises and falls like the tide. When the boiler is at rest, the water level is set to its proper level, but as the boiler starts to ‘do its job” the water level will drop as the water starts to steam out to the radiators. As we lose water to the system, the level of water in the boiler drops and as the steam condenses back into water, it returns to the boiler. The water level rises back up to its proper level and all is well. This is how it is supposed to work, right? Sometimes.
Many times you may find that the water level has risen above the ‘normal operating level” and need to find out why. We can only imagine what is happening as the water goes through its transformation and ride that train of steam and back to water again. Think of it like the commercials for cholesterol medicine on television where the arteries get blocked. As the water turns to steam, it leaves the boiler to travel to the radiators where it will lose its heat, turn to water and begin its travels back to the boiler. But wait, the piping that it has to travel along is getting old, and the water may be finding it difficult to make its way through the return piping due to contaminants that can clog it up. This prevents the water from its travels, and the level of water back in the boiler is getting lower and lower.
If there is a Low Water Cut Off (LWCO) installed on the boiler, this will shut the burner unit off so as to protect the boiler. Do I hear you saying that ALL steam boilers have low water protection? You would be surprised how many do not. The LWCO will wait for the water to come home to the boiler before allowing the burner to refire. Good for the boiler, bad for the customer. You see, since the boiler is not steaming, the radiators are not delivering the heat that the customer wants.
Now if the LWCO has an automatic water feeder connected to it, either a combination unit or separate this feeder is going to do its job, which is to add water to the boiler. That is what water feeders do when told to do so by the LWCO. If this is allowed to happen, when the thermostat is finally satisfied and all that steam turns back to water, all that water has to make it back to the boiler, eventually. Now you will find the water level in the boiler much higher than its normal level. Now if the customer has monitored the water level in the boiler, they will drain the water back to its proper level and the process starts all over again. The boiler is screaming for help, it is drowning in its own life blood, water!
Thankfully, there are LWCO products on the market that will wait a set amount of time to help with this problem. If you noticed, I said they only help with the problem; they do not solve the problem. The only way to solve the problem of clogged return piping is to replace the return piping. This is not a cheap fix, but remember, those return pipes have served well for many, many years are due their retirement. They have out lived their useful life.
I have seen many return piping replaced with copper piping. If this is kept below the water line of the boiler it appears to work well. Not my choice but it does seem to work well. Many installers I now see are using copper piping on the steam side as well, this is not good. In my opinion, the steam system must be piped in black steel pipe. Think of the steam system as a living, breathing object. As the pipes heat up when the full of steam, these pipes move. When these pipes move the threads on the piping allow some movement, the soldered copper pipes do not. Oh, the copper pipes will move, but the soldered joint will break and you now have a leak. Steam boilers require black steel piping.
This is only one of the possibilities as to why a steam boiler floods. We will explore more possibilities in the future, but, in the meantime, if have experienced a strange flooding problem on a steam boiler, drop me an e-mail. You can reach me at firstname.lastname@example.org