Hot Water Circulating Systems – hot water when and where you want it:

I recently did some research on some different hot water circulating systems (sometimes called ‘on-demand’, ‘recirculating’, etcetera) for a home remodel that I have been working on. Here’s a comparison of what seem to be the most common features, approximate costs for each, as well as some of the drawbacks.
Things to know about each type of basic hot water circulating system . . .

1.    On-demand hot water circulating system:
Installed cost: possibly the least expensive once installed, usually around $650+/- (because there is no return piping required)
Pump location: often placed below the farthest faucet away from the water heater
Return line:  none is required to be added; the existing cold water line is used as the return line (and can therefore take a moment to give you cold water at that location after you’ve received the hot water as it is back-fed slightly into the cold line)
Activated by: manually – by pushing a button at the point-of-use to get the hot water to the farthest faucet (and, therefore the other faucets along the path to it), which also means you may also need other ‘remote’ buttons near other locations where you use hot water – eg. second bathroom, a kitchen; pump shuts off as soon as the hot water arrives at its location; we found that a standard door bell button works for additional locations, although you have to disconnect any little lights inside as they will cause problems otherwise
Temperature of water: close to that set on the water heater’s thermostat as it’s just been pulled and delivered to you, if the hot water pipes are insulated
Timer: none
Thermostat: none>
Pump/control: these parts range from $350 and up; doesn’t need thermal by-pass required in next option below, as it’s part of the pump/control system at the farthest point
Remotes: anywhere from $100/ea and up, at each location where you might need hot water – depending how the remotes work, and the type of construction of the home, could be expensive to add remotes in other locations
Electrical requirements: – Ground Fault receptacle is required and usually not located near where you need it (in cabinet under sink) – unless the kitchen is the farthest point from the water heater; then you might already have a receptacle for the pump (if it’s not already filled with dishwasher and disposer plugs)
How this system works: Metlund D’Mand System Installation Video  specifically at 1:40-2:10 minutes

2.    Automated hot water circulating system – with the pump at the water heater and no return line installed:
Installed cost: likely just a bit more expensive once installed, usually around $700+ (no return piping, but a thermal by-pass valve is required)
Pump location: at or near the water heater
Return line:  none is required to be added; the existing cold water line is used as the return line (and can therefore take a moment to give you cold water at that location after you’ve received the hot water as it back-feed slightly into the cold line)
Activated by: timer activated, in conjunction with thermal by-pass valve opening as water cools down at farthest point
Temperature of water: approximately 100 degrees is how the thermostatic valve is set; when the hot water gets to the valve at the farthest point, it shuts off and the pump stops running at the water heater
Timer: on pump/control
Thermostat: none on pump/control as the thermal by-pass valve is the thermostatic control; it is pre-set and not usually adjustable, and it is placed under the sink at the farthest point from the water heater
Pump/control: range from $200-350; also needs thermal by-pass, cost up to $100
Remotes: not needed as it has timer
Electrical requirements: – Ground Fault receptacle is required near water heater
How one such system works: Watts Hot Water Recirculating System  Click through the ‘Features’ and ‘Installation’ videos

3.    Automated hot water circulating system – with the pump at the water heater and with a return line installed:
Installed cost: initially more expensive to install, usually $1,000+ (requires return piping)
Pump location: at or near the water heater
Return line:  required to be added; cost easily $500 and up, depending on a number of factors
Activated by: timer/thermostat
Temperature of water: close to that of the water heater’s setting, if is has run very recently, and depending on the user’s selected temperature setting
Timer: on pump/control; completely controllable by user
Thermostat: on pump/control
Pump/control: range from $200-350
Remotes: not needed as it has timer
Electrical requirements: – Ground Fault receptacle is required near water heater
How this system works: (images from PlumbingSupply.com)

Typical hot water system before a recirculation pump.

Common circulation pump installation.

Close-Up of pump installation.

This is the one I have used a few times: Grundfos UP 10-16B5/ATLC

And, now I’ve tried this: Metlund STS-70T-PF

Stay tuned for more
Remodeling Features!

Originally posted at: https://rdyoungscontractor.wordpress.com/