JAM News
Thursday, May 27, 2021

Are you treating those systems?

RADIANT & HYDRONICS - Dan Holohan

Water quality can impact the operation and life cycle of hydronic systems.

I was wondering about boiler chemicals and how many contractors (if any) were using them on brand-new systems. Do we need them? Hydronic systems are closed to the atmosphere, so what are we treating? I also wondered about the water we’re using. Is that any different these days?

So I asked some contractor friends. One said, “I think all new systems need, at the very least, to be power-flushed. Using a cleaner would be even better because it would help cut the oils, greases and fluxes, but how much of that stuff is in there really depends on how careful the pipefitters are.”

That’s always the X-factor on any job, isn’t it? How careful are the pipefitters? Are they looking to the future? That’s when bad things can happen.

“As for treatment and fill-water, it really depends on the quality of the job-site water,” my friend continued. “I look at hardness, pH, total dissolved solids and chlorides — and that’s at the very least. I’m not sure how many city or rural water systems’ supply water meets the specifications boiler manufacturers and tank manufacturers insist on these days. When hydronic systems combine copper, brass, iron, steel, plastic, aluminum alloys and various stainless alloys, the issue of water quality becomes much more important. I also think the quality of potable water nationwide is changing, not to mention the chemicals they add at treatment plants, and how they work in hydronic systems.”


Food for thought
That last comment got me thinking about the domestic-hot-water copper tubing in our house on New York’s Long Island. We replaced the same length of pipe twice in three years before we switched it all to PEX. The water ate right through the copper. Scary stuff. 

We also have a hazardous chemical plume in the aquifer under our town. It’s courtesy of the stuff Grumman dumped into the ground as they were making war planes. Our water district is adding lots of chemicals to our drinking water these days in an effort to counteract that nasty stuff in the aquifer. That may be affecting the copper, but no one knows for sure if that’s the case. 

Are you thinking about these things when you install a new system or a replacement boiler? 

Another friend commented, “I have been using Rhomar products for the last 10 years in systems that have a lot of rubber radiant tubing. It’s been a great help. As for treating a new system as part of the install, it depends on the system. If it’s an old cast-iron or steel system, I’ll treat it. If it’s a newer system with copper fintube radiators, I won’t treat it. I am starting to make the switch to Fernox because their compressed-gas applicator bottles make it easier to get the chemical into the system. It’s a lot cleaner and definitely faster.”


Pointers from hydronics pros
And then there was this from another contractor:

“I would not recommend makeup-water purification without first having everyone understand we are about to shift the chemical equilibrium of the system, regardless of whether it’s in good shape or bad shape. Taking an old scaled or corroded boiler and swapping it over to treated water is going to have a very real and very immediate impact that can be interpreted as bad. 

“Long-term water purification is good, but who is going to maintain it? Motivation is the key here,” he continued. “If you have a boiler or a system that has failed a few times from corrosion, you might have a client that is willing to play ball with you. But if you show up and see an impending disaster, and this is the first time it’s happening, or if the owner is new, then selling chemicals might be difficult.”

So bring an open mind and a lot of questions to whether or not you should treat that system because things can get messy in a hurry. 

I asked another guy I respect for some treatment rules of the road, and here’s what he had to say: 

“Unless there was a problem, I would only check for hardness in the water and its pH. If I can keep the pH at 8.5 I know I can eliminate iron corrosion at 180° F. That’s a big deal. I would also keep the hardness in bicarbonate form less than 10 parts per million. If there’s no copper piping in the system, I treat hardness and pH with straight caustic. For me, caustic is like a one-stop shop and it’s pretty cheap. It will take all the CO2 out of water in exchange for carbonate, and it will remove temporary hardness in exchange for more carbonate. It also converts permanent magnesium hardness to milk of magnesia, sodium sulphate, table salt and saltpeter.

“If there’s copper in the system, I won’t use caustic; I’ll use phosphate,” he added. “High pH in soft water with sulphates and nitrates can eat copper’s oxide layer, which is never a good thing. That layer protects against holes. And since hot water systems don’t cycle up in concentration like steam boilers do, it is not something I would habitually watch.”

And speaking of steam (if you work on those systems); keep the pH of the water between 7 and 9. A pH of 10 won’t allow the pipes to corrode, but if the pH gets to 11, the water will foam and that will ruin the quality of the steam, causing it to condense long before it reaches the radiators. The result is very uneven heat in the building. 

From another guy who’s had lots of experience with chemicals: “I am a strong believer in water treatment. I carry pints of Fernox F3 cleaner on my truck and sell it whenever I do a boiler cleaning. People like the idea of a clean system, inside and out. I go back a week or so after the installation to flush the water and add the F1 inhibitor. It’s an easy sell if you explain it well. People get lots of benefits from it. 

“I have also had success using these products on non-oxygen-barrier radiant systems, and open, wood-boiler systems,” he continued. “When checking the inhibitor levels several years later, I have found the water to be clean and clear. Every new system I install gets some form of treatment. They deserve it. Ask yourself this question: When you replace a component in a hydronic system, did it fail from the inside or from the outside? I read old books about the pioneers that first explored these rolling hills and valleys where I work. We have turned much of this land into an overpopulated, industrial wasteland. Those old books describe clear blue lakes and crystal-clear rippling brooks filled with trout. Those very same brooks are now called cricks and they are fishless, brown and dirty.

“We are polluting the water, above and below ground, and using that water to fill our heating systems,” he added. “There are a few contractors in the area using the treatments. There would be more people using those treatments if someone told them about it and explained how it works.”

He just did. 

A few more thoughts
People add glycol to hydronic systems, and then forget to tell anyone they did that. The glycol gets old, diluted, useless and very corrosive. We should be checking the water’s pH on every job.

A plant worker was told to add one scoop of a chemical to the system every day, and right on the suction side of the big, base-mounted pump (which is always the worst location for feeding chemicals). Lest he forget to do his daily chore, this guy added seven scoops of the chemical every Monday morning. Now he was done for the whole week. 

I met him because he couldn’t figure out why the pump’s mechanical seal kept leaking. Human beings sometimes do wacky things. Keep that in mind when you’re troubleshooting.

You can buy a tester that measures pH, total dissolved solids, conductivity, salinity and temperature. It’s not expensive, and it’s a great tool for every heating professional to own.

Do you have yours?

 

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