Hot Water Recirculation and PRV

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Rednima

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Hi Everyone,

Great forum. I wish I had found it much sooner. I was hoping you could help me. We just purchased a new house and noticed that it is taking a long time for hot water to get to the shower, which is the furthest from the water heater. We just had a PRV installed due to excessive pressure.

The PRV was installed next to the main in the front yard and the expansion tank installed next to the water heater. If we decide to go with a recirculation system of some sort (i.e. Watts, Grundfos, etc) will there be any potential problems installing it myself? The installation seems straightforward, but I don't know if the PRV will cause any headaches.

Thanks.
 

Terry

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The PRV is a non-issue as to how how the recirc would be plumbed.

What is more important, is getting the check valves in place, and making sure the expansion tank is within the water heater enclosed system. With check valves, it tightens up the system, and the expansion tank needs to be placed so that the exanding hot water can use it.

Grundfos makes a nice aquastat that will turn off the pump when the return reaches 108 degrees.
 

hj

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There is no problem nor are there any "precautions" to take if you use something like the Grundfos "Comfort" system. You just disconnect the hot line from the heater, attach the pump to the heater's hot outlet pipe, then reconnect the pipe to the top of the pump. The install the "bypass valve" under one of the furthest sinks. NO check valves or aquastats are needed.
 

WJcandee

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There is no problem nor are there any "precautions" to take if you use something like the Grundfos "Comfort" system. You just disconnect the hot line from the heater, attach the pump to the heater's hot outlet pipe, then reconnect the pipe to the top of the pump. The install the "bypass valve" under one of the furthest sinks. NO check valves or aquastats are needed.

In fact, we installed the exact system referenced by HJ a couple of years ago. Because the water heater is in the middle of the long house, there are runs East from the water heater and West from it. We put the bypass valve under the sink at the end of each run and voila!, warm water almost as soon as you turn on the tap, even (or perhaps especially) on the coldest days. Prior to that, I timed 30 seconds for a slight uptick in temp and a good minute for really warm water. Hot took even longer. Now you start with warm. It was worth every penny and we of course wish we had installed it years earlier.
 

Jadnashua

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FWIW, one study determined that if you use a timer so it doesn't run when people are unlikely to need hot water, it is actually cheaper to have one than not because of the wasted water, potential sewer bill charges, electricity to put it up if you have a well, etc. Keep in mind that if you waste 2-3 gallons each time you want hot water, that's also 2-3 gallons less capacity in your WH you can use for whatever purposes making it effectively look like a smaller WH. I've had one for about 10-years now and it's still going strong.
 

KevinPrz

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A second for the Grundfos Comfort system... took less than an hour to install just a few weeks ago. It use to take 90 seconds+ to get hot water in our main bathroom - now it's instantly warm, hot in a few seconds. The only compromise with the comfort system(which has not been an issue) is that your cold water will be warm for a few seconds before getting cold.

It was a welcome trade off, nothing like hot water in the bathroom on a cold morning. We're definitely going to see a savings with it as well between the gallons of water we used to fill our cesspool with cold water waiting for our shower and sink to warm up.

I'm not sure what adding a true recirc line would cost, but the comfor was ~200, and another 10 for the fittings needed to install.
 
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