# Inlet or Discharge side Check Valve on Residential Circ Pump



## CAPLMBR (Oct 29, 2010)

I have always known check valves for conventional residential hot water recirculating systems to be on the discharge side of recirculating pump and for there to be isolation valves on both sides of pump and check valve configuration. I have since run into a situation where this is being questioned. Also, in my area the water is extremely hard and wreaks havoc on check valves (sticking closed) and dead heading pump and eventually prematurely burning it out when installed at the base of the water heater where the T.D.S. is highly concentrated. Taco documentation shows on their 006 documentation that it is on the discharge side, however a tech with Taco said it doesn't matter. My question to him was "Then why do you not state either side is fine." Can someone please enlighten me with a code reference so that I may save face. I have the 2003 UPC Training Manual, but it doesn'[t specify. Thank you in advance to any help you can lend. Thank you. Jason (22 year plumbing contractor CA.).


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## Associated Plum (Nov 4, 2008)

That is the problem they have everything backwards the cold is coming in on the left


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## Plumbus (Aug 4, 2008)

From a code standpoint, it doesn't matter which side of the pump the check valve is placed. On Grundfos pumps with the check valve built in, it's installed on the discharge side of the pump for design reasons unrelated to code. A nice feature of their check valves is that a clogged one can be removed and replaced with a pair of needle nose pliers. 
As for code books, as of 1/1/2011 California is using the 2010 CPC. The 2003 UPC was never ratified by the California Building Standards Commission, thus no 2004 CPC.


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## Plumber patt (Jan 26, 2011)

I have a grundfos tech Manual and it shows to have the check valve upstream of the pump, and here in Ontario my teachers at school showed us to do the same


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## ZL700 (Dec 8, 2009)

Associated Plum said:


> That is the problem they have everything backwards the cold is coming in on the left


Not if your standing behind it


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