Replacement check valve

PC7060

https://forum.heatinghelp.com/discussion/193793/grundfos-alpha-15-55-pumps-dont-restart-after-long-shutdown#latest

hot_rod said:

I know the pump manufacturers have our best interest at heart with IFCs. However, they are too close to the discharge. They can trap air as @BenitoMN mentioned, and they are in fairly turbulent conditions. I suspect that is why some are short lived, they rattle their brains out. 12” or more downstream of a circulator, depending on pipe diameter, is where they would be better located. Always a hydronic specific check. No place for swing checks in hydronics other than power outage, overheat valves on fossil fueled boilers

@hot_rod - your predictions are scary.  The IFC in the Alpha2 in my system has failed open and is allowing reverse flow through hydronics heating zone during call for heat on the Indirect  DHW tank zone.  

I plan to remove the IFC from the circulator and add a check valve on the return side of the hydronics zone about 10” downstream from the dirt mag and 10” upstream of boiler  (fyi: no room to add check on supply side).  

Any recommendation for favorites check valve? 

I see Viega makes a press version (non-serviceable) available from supply house:

https://www.supplyhouse.com/Viega-79045-1-Propress-Check-Valve-Lead-Free?_br_psugg_q=viega+check+valve

Looked at the Caleffi serviceable valve. Can anyone tell me the difference between the two types other than press versus sweat? Looks like same cartridge but press version is much pricier. 

https://www.supplyhouse.com/Caleffi-NA51369-1-Sweat-Serviceable-Flow-Check-Valve-Low-Lead

https://www.supplyhouse.com/Caleffi-NA51366-1-Press-Serviceable-Inline-Check-Valve-Low-Lead

hot_rod

Same valve, different tailpieces. We source the press tailpieces from another manufacturer so it adds some cost

theowwm

I just installed a Caleffi NA51379 to address a similar issue to what you describe. I have a motorized three way mixing valve that does not automatically close when the boiler switches to DHW only. That was causing backflow through the valve to the boiler return. The check valve solved that problem. It had to fit into a tight spot, so the Caleffi was a good fit.

hot_rod

In some cases, rare but possible, you need a check on both supply and return to prevent rear end two direction flow. Ed has some graphics of that. Zone valves count as one end. Zone valves on the supply above the circ would eliminate the need for ICF checks.

Maybe some systems have some ghost flow but not homeowner noticeable,/ It get written off as solar gain, or addition heat from cooking etc.

The early series loop primary secondary piping were prone to ghost flow. So checks or deep heat traps had to be added on some systems. But you still needed one check with the thermal traps.

It seems tall vertical, large diameter piping is most prone to ghost flow via two direction movement.
For the same reason upper radiators on gravity systems over-heated I suppose.

PC7060

hot_rod said:

Same valve, different tailpieces. We source the press tailpieces from another manufacturer so it adds some cost

Order the Press version today, thanks!

PC7060

Caleffi check valve went in well; hefty unit located between the first DirtMag and the boiler input.   

I pulled the circulator to remove the plastic ICF; found the culprit for the failure. 3/4” copper string stick in the valve seat holding it open which ironically occurred during installation of a new Caleffi DirtMag located upstream from the circulator.  Thought I got all the debur pieces out but obviously not.  And of course it was on downstream side of the DirtMag. 

 

Added the second DirtMag for use as a dosing station.  Additional cleaning pass before the ECM circulator is a plus as well.