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Installation of hot water recirculating loop

Posted by linerrider (My Page) on
Wed, Mar 23, 11 at 22:22

I am planning to install a hot water recirculation loop on my existing system to facilitate a frequent high demand for hot water in our kitchen. My house is on a slab. I am planning to run a 1/2" pex line into the attic and then back down into the closet where the hw tank resides. The run in the attic will be about 30 feet and I plan to insulate. I plan to install a grundfos recirculation pump with thermostatic control and to use motion sensors to trigger the circuit to run the pump only during times of demand. My biggest concern is running the loop overhead in the attic. Will I be ok doing this? Also, would appreciate any input on electrical systems to trigger pump in response to motion sensors in baths and kitchen during times of use/demand. Thanks!


Follow-Up Postings:

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RE: Installation of hot water recirculating loop

"My biggest concern is running the loop overhead in the attic. Will I be ok doing this?"

As long as you make SURE the line is on the warm side of the insulation you should be OK.

Insulation does NOT stop movement of heat, just slows it down.

"Also, would appreciate any input on electrical systems to trigger pump in response to motion sensors in baths and kitchen during times of use/demand."

Look for a motion sensor with a form A or C relay output.
Use a 24 VAC transformer designed for thermostats.
The low voltage and power allow you to use MUCH simpler wiring methods.

You can then run thermostat wire to the transformer & pump location.

Use a common relay to turn the circulating pump on and off.

By using typical parts designed for HVAC you will save a LOT of money.


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RE: Installation of hot water recirculating loop

Temtrol DeltaT makes a TLC-X1 (thermal logic controller) which you plug any pump into and it will cycle the pump based on user chosen temperature using multiple types of activation methods. Occupancy sensor, Wireless, push-button, timer, etc. It allows adjustment of the shut-off temperature setpoint by the homeowner to their desired temperature. Temtrol makes Redytemp hwc systems utilize Taco 00 cartridge circulator pumps. But you would only the the controller TLC-X1

I would double check your flow requirements to ensure that whatever pump you use will deliver the hot water in an acceptable time period.

Here is a link that might be useful: hot water circulators and controllers


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RE: Installation of hot water recirculating loop

Looks at least a little overpriced at $150.


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RE: Installation of hot water recirculating loop

>Looks at least a little overpriced at $150.

Do you have another model suggestion? Plus any other components required.

I've just started a major renovation, and am wondering what the cost of adding a demand/motion sensor recirc loop would be, so I can decide whether it is worth it.

I'll have about 65' of return run.


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RE: Installation of hot water recirculating loop

It depends on what yo9u want the controller to do.

If you want a single package solution buy it.

I usually avoid that sort of thing since if any part breaks you have to replace the whole thing.

A separate timer, check valve, thermostat type transformer and relays should be less than $150.


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