# Which Add-on circ system do you use?



## JK949 (Mar 18, 2009)

We typically use the grundfos Comfort Series but we've gotten complaints of warm water through the hot and cold lines, found several sensing tees to be faulty and even water hammer? 

What do you like and why?


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## Phat Cat (Apr 1, 2009)

We use the same system and have had no complaints. Installed one in our own home a little over a year ago. No problems whatsoever.

Ours is set to run 6 - 9:00 a.m. and 5 - 8:00 p.m. Warm water in the cold is rarely a concern, in the summer our water is always warm at the tap anyway. Plus, warm water cools down much faster than cold water heats up.

Side note - our water usage dropped on average 50 gallons per day once we put the system in.

Has anyone used the new system G & F (Gosset & ???)or something like it? Their advertising slogan boasts of less energy waste. Grundfos uses the equivalent of a 25 watt lightbulb, this other system boasts the energy use is equivalent to a 10 watt lightbulb.


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## PLUMBER_BILL (Oct 23, 2009)

JK949 said:


> We typically use the grundfos Comfort Series but we've gotten complaints of warm water through the hot and cold lines, found several sensing tees to be faulty and even water hammer?
> 
> What do you like and why?


I use Grundfos and I have seen the hot in the cold line twice.

Both times it turned out to be a flapper leaking in the toilet.


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## JK949 (Mar 18, 2009)

I got a look at Laing's Autocirc systems and the Autocirc2's sensor looks way more robust than Gundfos and Watt's offerings, plus it's adjustable.


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## Richard Hilliard (Apr 10, 2010)

*re-circ*

With that system using the cold line as the return you will get hot water running in the cold water. If it runs hot a long time a couple of things may need adjusted. One is the water heater temperature. The faucet needs to run at a trickling pace and a temperature gauge under the water and see how long it must run before hitting 103 degrees. The valve under the sink is set to open at 93 degrees and shut off at 103 degrees. If the water heater is not turned up hot enough it will take a very long time to shut down if it does shut down.


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## Protech (Sep 22, 2008)

The only recirc system that I know of that truly yields a net energy savings and a lower life cycle cost is as follows:

-An oversized pump capable of moving the water at least 5gpm (like a Taco 008 for the average 2 bath house around here).

-Timer switches at all hot water fixtures with aquastat cutouts at said fixtures.

-Well insulated hot water pipes and recirc pipes (3/8" walled closed cell polyethylene or better)

-Dedicated recirc line back to heater.

-Motorized check valve wired in parallel with recirc pump (for reliability and better recirc demand flow rate)

Upsides to this system:
Actual net energy savings
Lower life cycle cost through energy efficiency (About 81% less costly to own over a 30 year period compared to the cost of the wasted energy and water that it replaces. To look at it another way, it works out to a net savings of about $5700.00 in today’s dollars over the 30 year life cycle of the system. That calculation was based of a savings of 50 gallons per day of hot water at my local water, sewer and electrical rates. Your mileage may vary. It also did not take into account water/energy cost inflation verses general inflation over the life cycle period.  )

Downsides:
-Higher initial cost than most recirc systems due to all the wiring, switches, aquastats, larger pump, motorized check valve. 
-Less convenience. requires behavioral changes on the residents part (must push the button and wait a few seconds before turning on the water).


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