Gorgeous Hydronic Piping – But Beware the Butterfly Effect

So the movement from the system is coming from proper and left to mix into the vertical 3” pipe, flowing down, or from the ceiling to the ground. The subsequent two full measurement tees are a part of the first/secondary connection, permitting the system loop (main) and boiler loop (secondary) to have movement charges that don’t have an effect on one another.

I used to be taught a few years in the past that the principle loop was the first and the department loop was the secondary. Made sense to me, however most boiler producers modified that round once they launched the idea with mod-cons.

These days, I say system loop and boiler loop when referring to main/secondary piping, low loss headers, or hydraulic separators. All three piping strategies have 4 connections: boiler provide, boiler return, system provide and system return.

The Child is Rising Up

I used to be educating a category the opposite evening, the Child was there. You keep in mind the Child, the man I used to be coaching years in the past. Effectively he interrupted me whereas I used to be explaining main/secondary piping to the category. Perhaps I used to be between factors, nevertheless it positively stunned me as a result of he’s normally fairly quiet.

He went as much as the whiteboard and drew a main/secondary connection carried out improper, on function. He had it configured like many installers have tried through the years, with the department connections of the tees piped collectively. It makes a pleasant sq. on paper, however isn’t the best way it’s presupposed to be.

He defined that the proper manner is with the widespread connection between the tees to be on the run of the tees, not the branches. He then drew a main/secondary connection for a mod-con boiler the suitable manner. A tear got here to my eye; the Child is rising up.

Much less Than Excellent

This job was piped appropriately, main/secondary connections might be in a horizontal or vertical orientation. The tees are shut sufficient and full measurement. Then there’s a discount from 3” to 1-1/2” on the boiler loop, which isn’t precisely right, however he referred to as at some point to say his becoming provider couldn’t furnish the suitable stuff and will he do it like that.

Typically I enable lower than excellent/right piping as a result of the distinction doesn’t have a lot impact on efficiency. On this case, the smaller than superb pipe measurement creates extra water strain drop within the widespread boiler loop piping, when each boilers are operating. This improve is well dealt with by the boiler loop pumps, which have further capability. They may run on the excessive velocity as a substitute of the medium velocity.

The installer took nice care to make the connections on the boiler loops the identical distance, what I name the butterfly look, since butterfly wings are usually similar. On this case, with the piping operating horizontally, he branched the return piping up whereas branching the availability piping down.

It seems nice, however creates an impact—a butterfly impact. Because it goes up increased than the return connection on the boiler, it has to return down. Every time a horizontal pipe goes up vertically and goes again down vertically, air can get trapped on the excessive level. When sufficient air will get trapped, circulation stops.

Troubleshooting

That’s precisely what occurred after we began up the boilers. The burners got here on, the water within the warmth exchanger received super-hot and the boiler went into a tough lockout. I had them verify the wiring for the boiler loop pump, since this is a sign that we didn’t have water movement by way of the boiler and discovered that they had been wired incorrectly.

With this boiler producer, the boiler loop pump is wired otherwise relying if it’s a business or residential boiler. He will need to have had his residential pondering cap on when he wired it. After it was re-wired, it did the identical factor. It was the air within the return line.

We had been in a position to purge the air out by closing the valves on the boiler provide strains and opening the boiler drains, one boiler at a time. It labored a few occasions however reappeared a few occasions earlier than we determined to go to lunch. Air was getting back from the system and getting trapped in these excessive factors on the boiler return strains.

At lunch, it was determined so as to add handbook vents to these excessive factors to bleed the air out, after leaving the system pumps on for the weekend to get extra air out by way of the in-line air separator.

That is the seventy second column I’ve written for CONTRACTOR. Once they referred to as me six years in the past, I stated I might attempt to do that for 3 years. I typically assume that I’ll run out of informative subjects, however then one of many subsequent website visits has that photograph op that I can ramble on about.