Flow check vs Zone Valve on radiant system

Steve Garson

The flow check on my radiant system doesn't really stop convection. As a result, my floors get some heat when they shouldn't. The convection of the hot water runs against the flow-check. I opened the valve and cleaned it carefully. I even replaced the Taco inner parts with a new one.

It isn't practical to install another one on the other end of the loop since it would be close to impossible to properly drain that pipe to be able to sweat it properly.

Is there any reason I shouldn't just replace the Taco flow-check with a Taco zone valve that simply will shut closed when the circulator is off?

Thanks,

Steve
Boston

Timco

I used taco flo checks on my system, and found out the hard way they are for horizontal installation only. If that is not the problem, you may need checks on the return, as hot water rises, and I had zones heat up slowly from that fact. (HW ghosting up through the zones not in use through the returns.) My local B&G dealer got me into some center spring silent check valves that threaded right in. I have had no problems since putting them on both sides.

T

Steve Garson

I have it installed horizontally.

bob young

gravity flow

you may have got some solder on the seat.which would prevent a tight seal. i prefer screw type for some valves & equipment for that reason. you could put a heat sink or spring check on the return.

bill clinton_3

I've come to prefer zone valves

for this. Works every time. Where applicable however, use one of those new circs with spring check. Cheaper and works well.

Joe Mattiello

Check valves less expensive

Check valves either integral or external will help with ghost flow. However, only .4 psi is required to open a check so when designing the system you should be certain not to create a pressure drop greater, because of ghost flow. You may need a check on the supply, and return, or if you can not stop the migration of flow, you can always install the flow control zone valve

Taco, Inc.
Joe Mattiello
Technical Service Technician
joemat@taco-hvac.com
401-942-8000 X 484
www.taco-hvac.com