Inline H2O check valve restriction on flow rate?

[Lu-Max]

Howdy.

(If you don't want to read all below, quick question: How much of a water flow rate restriction will be created if I install either a swing or spring check valve in a 3/4" (1" AquaPEX) line?)

Maybe I am putting far too much thought into this, but here goes...

I bought my current house about a year ago, recently my girlfriend complained to me about how long it took for the bath tub to fill up in the master bath. So I went into the crawl space and discovered that about 50' of 1/2" copper with 5, 90 degree elbows was used to plumb the master bath (the master bath was an addition by the previous owner). So I replaced both the hot and cold pipes with with 1" AquaPEX (about the same I.D. as 3/4" copper), the hot water line is insulated. As you can imagine the flow rate is now vastly improved. This house is supplied by a private well, no municipal water.

The issue now is that in the morning or when the hot water has not been used for a while, we are dumping a lot of water down the drain waiting for the hot water to arrive. I bought a Grundfos stainless recirculating pump and am putting a kit together to run a loop (second insulated 1" AquaPEX) for hot water up to the master bath. A timer will also be installed so that it only runs in the morning and evening when the M.B. gets >90% of its use.

I plan to install a check valve between the water heater and the pump for the hot water loop, either a swing or spring valve. I am curious as to how much the flow rate will be reduced by installing a 3/4" check valve into the hot water line? I don't want to restrict the awesome flow rate I now have too much. Or, should I buy a couple of 3/4-1" adapters and use a 1" check valve to prevent flow rate restriction?
Thanks in advance.

 

[Northislander]

flow loss in a 3/4 swing check would be negligible a springcheck would have a little more resistance but still very little
Most grundfos pumps come with a spring check option in the box
Also between circ. pump and tank i usually install a tee with hose bib than a shutoff than the tank, after install close shutoff and drain all air in the recirc. line out the hose bib so the pump isnt trying to pump air the grundfos comfort pumps will not self prime at all and the older UP's wouldn't do very well pumping air either
p.s. don't forget to open that shutoff before powering pump

 

[Lu-Max]

Thanks Northislander.
So is the hose bib in your setup at the highest point in the loop?
I was considering adding a Valmatic water/air release valve at the top of my loop to automatically purge air from the water line loop.

 

[Northislander]

No the hosebib doesn't have to be at the highest point just install it between pump and tank to flush all the air out of recirc. line before turning pump on for the first time.
Only time i have installed air releases is on engineered jobs or well water systems with lots of en-trained air in the water

 

[ctfjr]

I'm not sure I get this Lu-Max. On every recirc line I've seen the pump is on the return run, near the water heater and the check valve is between the pump and the water heater - at the cold water inlet to the heater. It's purpose is to prevent the cold water from flowing thru the pump in reverse and going into the hot water at your fixtures.
The check is not in the flow of the hot water line, only the recirc line back to the heater. It won't affect your flow at all.

 

[Lu-Max]

I'm not sure I get this Lu-Max. On every recirc line I've seen the pump is on the return run, near the water heater and the check valve is between the pump and the water heater - at the cold water inlet to the heater. It's purpose is to prevent the cold water from flowing thru the pump in reverse and going into the hot water at your fixtures.
The check is not in the flow of the hot water line, only the recirc line back to the heater. It won't affect your flow at all.

Interesting you should post this as I had spent the last hour or so googling various hot water re-circulation setup diagrams and PDFs and saw this very same thing. I have now changed my plan to install it as you described with no effect on flow rate to the master bath. Thanks.