Counterflow Steam Systems
In a counterflow steam system, the supply main is pitched upwards as it moves away from the boiler. This arrangement causes the steam and condensate to flow in opposite directions within the supply main. Here are some key points about counterflow systems:
1. In a counterflow system, the steam and the condensate in the bottom of the steam main are both running in opposite directions, which means they are counterflow to each other.
2. The steam travels away from the boiler, while the condensate flows back toward the boiler.
3. The main supply pipe slopes upward as it extends away from the boiler.
Piping Characteristics:
1. Counterflow systems require larger pipes due to the opposing flow of steam and condensate.2. The pitch of the counterflow main must be carefully designed to accommodate both the steam and the returning condensate.
Distinguishing Features:
1. Look for a drip pipe at the beginning of the main near the boiler. This drip pipe is a characteristic of counterflow systems.
2. If the system main is connected to the boiler and runs out without having a pipe at the end that returns, it is likely a counterflow system.
3. Conversely, if the main turns back toward the boiler with a smaller pipe at the end, it is a parallel flow system where steam and condensate run the same direction.
There are a few points to keep in mind when piping in a counterflow system to a steam boiler. You can see by the above diagram the low point of the piping is at the boiler. There will not be any return piping from the other end of the basement or end steam main. It is important to pipe the steam boiler riser to the top of the counterflow system pipe. This keeps a lot of condensate draining back the boiler riser dripping through the steam chest of the boiler. If this happens it will decrease the amount of steam in the boiler by cooling off the steam causing it to condense. The drip for the counterflow system should come from the end of the main near the boiler to get the condensate back to the boiler.
There are a few points to keep in mind when piping in a counterflow system to a steam boiler. You can see by the above diagram the low point of the piping is at the boiler. There will not be any return piping from the other end of the basement or end steam main. It is important to pipe the steam boiler riser to the top of the counterflow system pipe. This keeps a lot of condensate draining back the boiler riser dripping through the steam chest of the boiler. If this happens it will decrease the amount of steam in the boiler by cooling off the steam causing it to condense. The drip for the counterflow system should come from the end of the main near the boiler to get the condensate back to the boiler. The way this is piped if the water level drops enough or the boiler is surging the steam can enter the drip line and into the steam main. This will cause heating problems or no heat completely. Here is another diagram offering another style of piping which is also better in my opinion and probably more acceptable due to the near boiler piping as per the manufacturers diagrams. The drop before the Hartford loop will keep a water seal between the boiler piping and the system drip.
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