Hot water delay

[bruno]

I'm hoping I can find some insight on this forum. Thank you in advance!

I am in a 6 unit condo, we have a hot water recirculation loop with pump on a timer. The system has no balancing valves. My kitchen faucet takes a long time to receive hot water. Below are the times and temps I recorded to receive hot water. For reference I've attached a layout diagram and images. My unit is #5.

Times in min:second

With pump on
30 seconds = 71*F
1 min = 103*F
1:30 = 115*F

With pump off
1:00 = 86*F
2:00 = 89*F
3:00 = 88*
4:00 = 88*F
5:00 = 89*F
7:00 = 95*F
13:00 = 111*F

When the pump is running the faucet will eventually receive 125*F, which is the set point at the water heater.

The worst case, when the pump is off, occurs when no one else in the building creating no demand at the end of the line to pull hot water. My bathroom fixtures do not have the same issue as the kitchen, presumably because it's closer to the water heater.

After reading some articles on here I thought the remedy could be a check valve after the last fixture; in the crawl space under unit 2. But then I noticed what looks like a check valve after the pump; see attached image. With a check valve after the pump it would stop a fixture from pulling water from the return line, right? Even if the check valve and the fixture are that far away from each other?

Thanks again,

Bruno

*edited for clarity

 

[Jadnashua]

Water will flow via the least resistance path. The return should nominally, only need one path which forces the water from one end to the other without multiple side taps. IF each condo has a common feed, and they tapped the hot for return in each unit, without some balancing, you'd never get it even. If there were only one return tap and it was at the furthest unit from the WH, then that hot water would need to pass by every condo's inlet, and other than from the pipes radiating and losing some heat, you should have max hot water temp after only draining from your main inlet to the fixture in use.

 

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[bruno]

My apologies for the delay in reply. Thank you for the reply Jim.

We have a common hot supply line that runs under the building. All units tap into it for hot water. At the end of that supply line it returns to the hot water heater. If I'm understanding you correctly that is the 2nd scenario you described. Hopefully adding the balancing valves on the return, near the pump, will remedy the situation.

Thanks again.

 

[Jadnashua]

A return line without a check valve and a working pump, and when you try to access hot water, it may be coming from the return line if the resistance is less. That typically means pulling it from the cold end of the WH.