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Surely, someone here has actually seen a Taco flowcheck operate?

Posted by davidrt28 (My Page) on
Sun, May 11, 14 at 19:44

Trying to assess a very old radiant slab system for eventual update. Converted the house to scorched air and will never be happy with it, even if humidified.
I want to figure out if the existing taco flow checks are still working correctly. Is the pin at the top supposed to bob up and down with operation, or does it merely damper the motion of an internal, invisible part? The electricity has been disconnected so I can't just turn the circulators on. The modern ones have what looks like a thumbscrew, but mine just has something like a button that seems to have no threads or slots. They don't move with hand pressure and I'm worried if I take a wrench to them, a leak will spring. System is huge and must contain hundreds of gallons of water. I did install a new gauge about 10 years and the system is at the same pressure it was 5 years ago when I shut it off, so there are no leaks. Plumber who was afraid (his own admission) to take on the overhaul job 5 years ago told me to never let fresh air get into it.

Follow-Up Postings:

RE: Surely, someone here has actually seen a Taco flowcheck opera

Was your system designed with isolation valves to either side of the Flo Chek? How long has the system been sitting? The electricity is entirely disconnected?

It is unusual for them to be stuck shut - stuck open is a much more likely failure scenario. If you have isolation valves on either side of the Flo Chek, it can be checked out and repair (if necessary) very easily. Turning on a circulator is still going to be the easiest way to test the valve.

Here is a diagram of what the internals of your valve should look like.
Taco Flo Chek

RE: Surely, someone here has actually seen a Taco flowcheck opera

I assume from your diagram and what you say, I should see the pins pop up if the circulators are on. I can probably rig them up with an extension cord to be sure.

Sadly the biggest weakness of the system, IMHO, is a lack of isolation valves. In fact, I was scrutinizing the flowchecks because I will want to use them as isolation valves. There are return isolation values before the circulators. But if the circulators and boilers replaced, I will need the flowchecks to stop the loops from draining. The plumber told me once the loops drain, it would be a pain to get the air out and perhaps impossible because the loop trim valves are rusted shut. And the air would corrode the pipes.
The funny thing about mine is they have a little marking on the head/cap of the shaft that goes:


where the carat symbol ^ is an up arrow. The head of the shaft screws onto the shaft, but you can obviously only turn it in the direction of <---- because turning it the other way just unscrews it. On the side of the shaft is tiny pin that fits into groves holding the shaft. So I guess to "lock" it, you just have to overcrank the pin so that it goes back in the grove. (thus, "open" is really open or close) All of the pins are in the open position.

Wait a sec. I think I'm just figuring out how this thing works.
All of the zones heat so I'm sure the valve is either open or opening correctly. Was the plunger something durable like brass? I think "open" up arrow means you want to pull the pin up and lock it on the seat of the shaft sleeve. Open side arrow <-- just means you are releasing the pin from the groove in the sleeve. So in other words there are 3 operating states: fully closed - pin on shaft locked in sleeve, NO water flows. Normal operation: pin in channel on sleeve, can move and up down on its own. This is the way they are all set now. And finally: fully opened and locked. Water can freely flow in either direction if you want to gravity drain. You lift the head of the shaft and twist to set the pin on top of the shaft. Does that sound right?

This post was edited by davidrt28 on Mon, May 12, 14 at 21:02

RE: Surely, someone here has actually seen a Taco flowcheck opera

"The plumber told me once the loops drain, it would be a pain to get the air out "

You can purge the air by using a pump with about 30 lbs of pressure. Do each zone seperately, shuting off the others at the circulator.

You don't need a bleeder valve.

RE: Surely, someone here has actually seen a Taco flowcheck opera

Thanks Geoffrey. You aren't a licensed plumber in MD by any chance? (haha) I actually appreciated my plumber's honesty in saying he thought there were too many variables and risks given the age of the system. But when I have the spare cash I will update it, risks be damned. It was such a nice system. Totally quiet, extremely warm. 67F in radiant floor heating is about the same as 72F in forced air.

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