phc january 2019 www.phcppros.com.com
using it at 65 degrees to 70 degrees indoor air temperature? It works for me, but it's not up to me. It's up to those inhabiting the space and each one of those creatures has a different creature comfort zone. There are plenty of other control settings to investigate such as cascading multiple boilers, ramping, boosting, the use of a domestic hot water indirect tank, offsets, differentials, warm weather shutdown temperatures and pump exercising. Not all boiler controls are created equal. Do your homework. Flush the condensate line: Easy enough, right? Use an acid neutralizer kit. The condensate from these boilers is acidic and you don't want it attacking your plumbing pipes. Not to mention the fact it's required by code in most areas. Check static and dynamic gas pressure: This is critical. Please don't even attempt doing a combustion analysis without first checking gas pressure while the boiler is idle (static gas pressure) and while it's operating (dynamic gas pressure). It should be, here's that phrase again, within the manufacturer's specifications. Check voltage polarity and system ground: If your hot and neutral are crossed, you're going to have flame rectification problems. If you have a poor ground, the flame rectification circuit will be marginalized. Correct as needed. Check boiler piping to verify it meets manufacturer's specifications: This is important, as well. With only a few exceptions, modulating condensing boilers hold very little water; two to three gallons at best. For that reason alone, I recommend using a low-water cut- off on every mod con boiler. It's not an inexpensive investment. It only makes sense to protect it as best as possible. Boilers with water-tube heat exchangers are highly restrictive; fire-tube heat exchangers are more forgiving. For these reasons, make sure you pipe them correctly, ensuring proper flow through the heat exchanger. Its life depends on it. The mod cons with water tubes must be piped in some variation of primary/secondary piping, whether it be closely spaced tees, a hydraulic separator or a buffer tank. If you're not entirely sure on the details of primary/ secondary piping, do whatever it takes to make sure you are. Start with a piping schematic. Don't make it up as you go along. That approach rarely ends well. And unless you're really polished on designing hydronic piping systems, I'd recommend the same thing for boilers with fire-tube heat exchangers - unless they have a high water content. I can only think of two; one manufactured by HTP and the other by Viessmann. Check system water quality: Would you knowingly pump contaminated gasoline into that tricked-out work truck of yours? No. Who would? Then let's not put contaminated water in our high-end hydronic systems because you're going to get the same result; machinery that won't perform as the manufacturer intended. We didn't pay too much attention to this in the past but with today's high-end equipment, boiler water chemistry is more important than ever. Hardness, pH balance, TDS and chlorine play a crucial role in the lifespan of the heat exchangers. The boiler manufacturers will provide some ranges you'll need to be within. Clean your piping systems before connecting them to the new boiler and add conditioner after the new boiler is installed. For additional information, check out Caleffi's idronics "No. 18, Water Quality." Don't forget the usual tasks associated with a boiler clean and tune; check for gas leaks, flue pipe pitch and integrity, health and safety issues, pump maintenance, tank pressure check and adjustment, clean y-strainer, flue draft, water leaks, etc. Your brains, eyes and ears are your best troubleshooting tools. Keep them open and your job will be easier.
The Mod Con Squad
They were young people in trouble with the law. Pete, who was wealthy, stole a car. Linc got arrested during the infamous Watts riots. Julie ran away from her troubled past. Everything they did in their past was done with felonious intent. But they redeemed themselves. They completely reinvented their game. We've got to be reinventing and improving our game, too. More than ever, we need to raise the bar in our trade to continue its growth and attract young technicians. If we don't, who or what is going to replace us? I can't speak for anyone else but when it comes to our trade, if I don't know something or don't know how to do something, it bothers me to no end. It bothers me enough that I do something about it. I'll go to seminars, take classes, watch videos, read a book or a technical manual with all the zeal of an OCD action figure. How about you? Are you ready to become part of the elite? Part of the Mod Con Squad? Yes? Let's go to work. l Stephen Minnich has nearly 40 years of experience in the heating industry, primarily installing and servicing hydronic systems. He most recently operated Minnich Mechanical Design, based in the Chicago suburb of Elk Grove Village. Minnich is currently an HVAC consultant for Elevate Energy, Chicago.
Inspect the ceramic part of the flame sensor to make sure there aren't any hairline cracks. Photo credit: Steve MinnichPrevious Page