Water contamination questions

kaama82 · October 2018

Hello. I have some issues with my Radiant heat system in my pole barn. I am hoping to gain some knowledge by posting this here. I have roughly 3000 sq ft of heating space divided into 3 zones. My system came from RadiantTec. Yes I have read all the negativity about them, And I'm in complete agreement with others. I am using a Tagaki wall unit on propane for the heating source. Here lies the problem: Sometimes my system works fine, other times not so well. I'm using Hecules Cyrotek 100 for my glycol mix. It seems that my water forms some form of contamination as the system runs. The contamination gets so bad that I start to lose flow. I then shut the system down and I filter the water through a 25 micron bag to clean out the contamination, clean the strainer, and the filter on the Tagaki and then start the system back up again. Sometimes this has to be done every 2 days or so. Sometimes longer in between. The contamination appears to be pale green in color. I have ran cleaners through the systems, and flushed with fresh water numerous times. The contamination comes back. Any help would be greatly appreciated.... Thanks Todd.

hot_rod · October 2018

why do you have glycol in the system?

kaama82 · October 2018

Honestly, I thought it was needed for the water, meaning I was under the impression that glycol would help keep the water from getting out of whack.... I am located in Michigan, so I wouldn't want a problem with freezing etc.

hot_rod · October 2018

Not sure what you mean by working fine some times not others? Does the boiler lock out?

Adding glycol requires the circulator be upsized, and with tankless heaters, if that is what you have, you often are starting with a high pressure drop heat exchanger.

If the system starts form a cold condition that glycol will be thick and hard to circulate.

Glycol has color to it, but should not have dirt or contaminates, what type of particle.

Tankless have small strainers often times, the mesh may be too fine for the fluid you are trying to circulate.

If you premix glycol, first it needs to be hydronic glycol and it needs to be blended with RO or DI water, or you risk sludge formation form the minerals in the water reacting with the glycol.

A proper flush would involve a hydronic cleaner (soap) to cut and remove contanimrntes like oils, glycol sludge, etc. plain water may not be cleaning the system properly?

If the system is left unattended for extended periods in the winter, 30- 35% glycol is used for insurance against freezing. a warm radiant, concrete slab can usually go a few days before freezing starts, unless tubing is outside the building.

Low temperature alarms and phone dialers are another option.

nibs · October 2018

Are you filling with city water, if not, you may have the same problem we do. Our water is not chlorinated and contains what is locally called 'bio film' which clogs up valves etc. Our system will need 16 gallons +/- and we will fill with store bought water.
To keep the bio material out of our hot tub, we built a 55 gal sand filter and the water stays crystal clear with no chemical use.

kaama82 · October 2018

hot rod said:
Not sure what you mean by working fine some times not others? Does the boiler lock out?

Adding glycol requires the circulator be upsized, and with tankless heaters, if that is what you have, you often are starting with a high pressure drop heat exchanger.

If the system starts form a cold condition that glycol will be thick and hard to circulate.

Glycol has color to it, but should not have dirt or contaminates, what type of particle.

Tankless have small strainers often times, the mesh may be too fine for the fluid you are trying to circulate.

If you premix glycol, first it needs to be hydronic glycol and it needs to be blended with RO or DI water, or you risk sludge formation form the minerals in the water reacting with the glycol.

A proper flush would involve a hydronic cleaner (soap) to cut and remove contanimrntes like oils, glycol sludge, etc. plain water may not be cleaning the system properly?

If the system is left unattended for extended periods in the winter, 30- 35% glycol is used for insurance against freezing. a warm radiant, concrete slab can usually go a few days before freezing starts, unless tubing is outside the building.

Low temperature alarms and phone dialers are another option.

Yes, what happens is I lose flow because the filter on the Tagaki starts to get dirty. I then have to shut the system down and clean the filter and the strainer on the system. The glycol is Hercules Cyrotek 100. I do believe that it is a Hydronic glycol.

What is RO or DI water?

I have used the Hecules brand boiler cleaner to flush the system. Do you think soap would be a better choice? How much soap is needed?

I do have one loop that exits the building for a snow melt application.

kaama82 · October 2018

nibs said:
Are you filling with city water, if not, you may have the same problem we do. Our water is not chlorinated and contains what is locally called 'bio film' which clogs up valves etc. Our system will need 16 gallons +/- and we will fill with store bought water.
To keep the bio material out of our hot tub, we built a 55 gal sand filter and the water stays crystal clear with no chemical use.

I have used both distilled water and clorinated city water, I'm not sure if it made a difference.

hot_rod · October 2018

I'd be tempted to leave the strainer out

It' probably more for when the boiler is used as a domestic water heater and sees fresh, possibly dirty water added constantly. In a closed loop system you should not have 'stuff" in the fill water.
Yet another reason not to use tankless water heaters as hydronic heat sources.

Add a dirt separator upstream of the boiler. Dirt separators catch and trap particles in the bowl and avoid reducing flow like a strainer does, much better for hydronics and can filter out particle down to 5 micron.

I'm not sure where the crud is coming from?

Zman · October 2018

How is your system piped? Do you have pictures?
What concentration glycol are you using?

kaama82 · October 2018

Hot Rod, here are some pictures of my system. I have a dirt separator already. I believe its a Caleffi. Its in the pictures. Also attached pictures of the matieral in the system. I have ran a boiler cleaner through the system for 2 hours, Flushed with tap water, used compressed air to drain system, filled with distilled water, drained again with compressed air, and now filled back up and this foreign matieral is still present. I'm about done with this system....

kaama82 · October 2018

Now the foreign matieral that's still present.

hot_rod · October 2018

Green particles sometimes indicate copper or brass breakdown, check the ph of the glycol.

Note all the green blue stains when glycol has seeped out.

Personally I'd remove all the strainers and let the Discal do all the work. It will remove all those particles down to a 5 micron!

Most important a separator removes particles and stores them in the bottom of the Discal, not in the fluid path.

Clean system with hydronic cleaner, flush, add pre-mix glycol, or mix onsite with DI or RO water.

Be sure the system is air, and O2 tight, corrosion happens when O2 constantly gets in. Close off air vents when the system runs quietly.

kaama82 · January 2019

A little update. I have since drained the system of glycol. I have eliminated the loop that went outside for my icemelt area. I have cleaned the system with a solution of TSP. Flushed the system multiple times to assure myself that all foreign material is gone. I have refilled the complete system with DI water with ZERO glycol and low and behold the system is running beautiful. No issues now ....

kcopp · January 2019

I avoid Glycol period.... There has to be a VERY good reason to truly NEED it.

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