Boiler Replacement: Always Question the Existing Piping

Here’s a war story for you. I stood with a guy in the basement of a small commercial building on Long Island a few winters back. Several weeks earlier he’d attached a brand-new boiler to a 2½ inch header that had been there for 60 years. Now nothing worked. The burner ran on and on, but half the rooms had no heat. The water hammer was incredible. So were the fuel bills.

Needless to say, getting paid was somewhat difficult.

When he was quoting the job, he’d noticed the boiler manufacturer’s instructions called for this particular boiler to have a 3-inch header. He’d actually taken the time to check.

But apparently the message just didn’t sink in. It didn’t make sense to him that the old 2½ inch header which had served the building so well for so many years wouldn’t work with this new boiler. How could it not work?

He figured condemning that 2½ inch header now would be like turning your back on an old friend. Besides, changing old headers is tough work. He knew his competitor (that lazy so-and-so!) wasn’t going to change the header. And if his competitor wasn’t going to do it, why should he? He also knew if he threw the extra labor and material for a 3-inch header into his quote he’d probably lose the job!

So he let it slide and now he was stuck with the results.

The funny thing was (and I’ve seen this happen so many times), he just couldn’t accept the possibility that the header was causing the problem. After all, it had been there for 60 years! It had no moving parts. He knew the manufacturer had called for a 3-inch header. In fact, he kept glancing back at the installation instructions. But he just couldn’t accept this as the cause of the problem.

So he went to work on the oil burner, increasing and decreasing the nozzle size until he’d exhausted all possibilities. Then he skimmed the boiler, added a case of chemicals, flushed out the returns, and replaced most of the air vents. He did work he’d never planned to do, and he did it all for free. He got to the point where he wished that lazy so-and-so competitor of his had gotten the job.

That’s when he asked me to take a look. I checked the boiler installation instructions against what was there. Then I suggested he increase the header size to 3-inch.

“But this one’s been here forever!” he said. “Why shouldn’t it work?”

“Because the replacement boiler’s different,” I said. “The manufacturer wants 3-inch. Just for laughs, let’s try it their way.”

“What happens if I do it that way and it still doesn’t work? Huh?”

“Let’s try,” I said.

He was still skeptical. He smirked and shook his head in disbelief, but he was at the end of his rope with nothing more to lose, so he gave my suggestion a try.

It worked.

Don’t try to save money on a steam job by under-sizing the pipes. You will always lose. Every single time.


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