Dirt in Radiant Heat System

1daveman

I have a relatively new system, that has a 70 gallon tank that is heated with solar. The water flows from the tank through a Navian peak flow filter, then into a Navian propane tankless that turns on when the PV heated water is not hot enough

When I first turned it on the system flow bogged down after running only a few hours. After much research I was able to determine the Navian filter was getting clogged by debris. After many many many flushes I was able to get it to clear up, and have run it for a few months. I keep changing the filters and they continue to get additional debris. I really do not want my tankless to get clogged up. I cannot keep using the navian filters nectar m because they are expensive, but also have a temperature limit of only 100f, which won't work.

Reading this forum I have seen others with similar issues, and the consensus seems to be that the debris is caused by rust, so the solution is to use stainless steel pump and 02 barrier PEX.

I checked and have a stainless steel Alpha2 pump and 02 barrier Pex, so I am not sure what is causing the debris.

Regardless, after reviewing other posts on this forum, I was thinking I would replace the Navian filter with the Dirtmag Pro, and adding something like Fernox solution to the water.

Does this seem reasonable? Does anyone have any other suggestions? I asked an earlier question and got some great feedback, and would appreciate any help anyone can provide

hot_rod

A good flush after you add a DirtMag should be adequate. I use a conditioner in my hydronic and solar systems for extra piece of mind. Rhomar, Fernox, Adey, Axiom, many others.

Do you have a tight leak free system? No fill water being added ?

Do you have a drainback solar, since you didn’t mention glycol?

DCContrarian

Are you producing hot water or water for heating space?

Is the system open (water is used and new water replaces it) or closed (the same water circulates all the time)? If it's closed, is it pure water or have you added anything to it?

What is your tank made of? The solar panels?

Do the solar panels have drainback?

1daveman

Thanks for the questions.

My floor heating system is a closed system, and since I am in Arizona, I have only filled it with water. I don't think I will have a freezing problem.

I was not clear about my solar. My home is off grid, so I have solar panels and batteries to run everything. The batteries are typically charged by mid to late morning, so I divert the excess power to 48vdc heating elements in the water tank. The tank has a coil that the DHW flows through, but that water is isolated from the floor

Both DHW and Floor go through separate tankless water heaters that use propane as a backup.

I am not sure what the tank is made from, I assume stainless but really don't know. I will look into that.

Thanks again

DCContrarian

Corrosion happens when metal reacts with oxygen dissolved in the water. In a closed system, after a while all of the free oxygen should be reacted, and corrosion stops. That's assuming that the entire system has an oxygen barrier and there's no way for new oxygen to get in. Similarly, if the water you filled the system with has impurities in it, they can precipitate out, but over time they should all come out.

So if your system is closed, even if it starts out with debris, over time it should get very clean.

So you have an automatic water filler? I would turn it off. If your pressure then drops, you're leaking somewhere, and fresh water is bringing in gunk.

1daveman

Excellent, thanks

I don't have an automatic water filler and the pressure remains constant, so I am pretty sure I don't have a leak. I will install the Dirtmag and add some Fernox, and it sounds like over time the problem will dissipate.

Thanks again.