Ghost flow in potable radiant loop, mineral buildup on FloChek.

Albany Chris

I have a radiant floor heating loop coming off my Vertex HWH that has very strong ghost flow. Enough to warm the floor... It is a single loop using potable water. I have a Taco 3/4" brass flo chek, but the mineral buildup quickly stops it from working and has now caused the internal parts to fail.

Is there a different check valve that can better handle the mineral buildup and will be strong enough? Or will piping in a large heat trap in the tubing (1/2" pex) negate the ghost flow? Or should I just install a zone valve?

This system is in my own house and I am aware of the risks of using potable water and even have a sign on the system in case I get hit by a bus.

GBart

You found the cause of your overheating, question is what is making the deposits, do we have piping with an 02 barrier?

Rich_49

Barrier tubing would make no difference in this case since it is an open system it seems .

hot_rod

Not all checks are rated 100% bubble free.

Here is a Caleffi NA12153, 3/4" version that has a Neoperl brand spring check inside. The same type used in most hydronic circulators these days. About a 1/2 psi pop.

Low headless, tight seal, noise free design.

Remove the check before you solder it in, cool and reinstall the check.

Probably find them at online suppliers.

GBart

I missed the open/potable part, duh, S/S parts perhaps or plastic guts like suggested.

Albany Chris

Thanks Hot Rod, as always. I might need two of them as the flow is so strong, but that seems like it would be more resistant to mineral buildup and easier to clean if it does buildup.

Albany Chris

Any thoughts on whether a zone valve or the Caleffi check would have less issues with mineral buildup? Do you ever see buildup on the rubber / neoperl check valves? I don't but mine are all in sealed systems. I'm starting to think that the forced full movement of the rubber ball in the valve might be more effective. Plus I'm not sure one Caleffi check will be enough. This will be my 3rd attempt so I'd like to get it right this time. Thanks.

hot_rod

You kinda need to know what the pressure differential is to determine which valve would be best. A high shut-off pressure zone valve, a ball valve type ideally if you can find a low lead version. I doubt the Caleffi/ Neoperl has much if any higher pop that the one you have.

The Taco zone sentry has a high Cv and 125 psi shut off, but is it low lead?

The Caleffi Z one is a 7,5 Cv, low lead valve, but a 20 psi shut off. It gets used in a lot of potable water applications.
The 1 Cv valve has a 75 psi shut off, but it may add too much pressure drop.

If

Rich_49

http://www.taco-hvac.com/uploads/FileLibrary/102-484.pdf

Albany Chris

I am following up on my own post in case it helps others with their situation.
I added about 15ft of pex, looped to make a heat trap. This has stopped the ghost flow without using a check or valve. Coming out of the side tap of the Vertex HW the pex goes down 5' to the floor, back up 7', down 7' to the floor, and up 4' to the circ and the rest of the circuit. This may be a much bigger trap then needed (it's actually a double trap).

hot_rod

A thermal trap, nice simple solution.