Where to put the pump

RobinInCali

I have a 5 zone pump boiler panel with 3 zones connected—two large 26 grundfos pumps and a smaller alpha pump. Navian 200btu boiler with a Taco Pump controller, with only 3 zones being connected currently and the indirect tank, so there is room for two more zones, and all run at 160 degrees. Two of the pumps each run large cast iron radiator systems, and one of the zones is an alpha pump which runs a small baseboard radiator zones.

So: I need to add the 4th zone for the carriage house. We will have two modern steel panel radiators 14k each, for 28k btu total zone. Normally I would add this 4th zone pump to the current boiler panel inches from the other zones, but there are two problems. First, I have no thermostat for this zone, as the wiring that was run has a continuity problem and can't be used. Also, the radiators I'm connecting are in a carriage house 150 feet away from the panel with its own manifold (the 1" pex supply/return tubing are very well insulated and lose only half a degree in each direction). So, if I connect these radiators I would have to install a wifi-controlled thermostat out there. But I thought of an alternative.

I was thinking installing the Caleffi Mixing station with manifold inside the carriage house, would allow me to access the pump electrical on/off, mixing valve to nail the right temp and turn it on and off at the pump location. No need for a wifi thermostat set up. Or should I still with the pumps on the main boiler panel and install the wifi thermostat?

Seems to me a hard wired on/off pump and mixing valve make better sense. But I thought I'd ask.

Jamie Hall

I take it there is a feed line and a return line from the manifold in the house to the carriage house? Yes? Then there is no good reason why the pump controlling the circulation in the carriage house can't be in the carriage house. The only thing you would have to watch out for is the pressure drop in the feed line from the house to the carriage house, and thus the inlet to that pump — most pumps should have at least 5 to 10 psig at the inlet when they are running.

All your control wiring for the thermostat and the pump would be in the carriage house. How the boiler would be controlled is another matter — and that depends on what controls the boiler now. It could be a flow switch on the feed or return, for instance, right at the existing house connection.

hot_rod

is it a boiler or a tankless heater. Those 26 series pumps sound big?

Any pics?

GroundUp

What's serving the indirect? Sounds like maybe one 26-99 is for the boiler circ and the other is the indirect, then the Alpha does all 3 heating zones? Sure you could run the circ in the carriage house, but how would you signal the boiler to fire?

Jamie Hall

Flow switch, @GroundUp . Pump in the house, flow switch near the boiler.

hot_rod

RIB has a version that works down to .25a

That would work on most PSC circs Im not sure about an ECM on low setting?

IMG_8757.jpeg

for 35 bucks, ill order one one give it a try

RobinInCali

I’m running off a Navien 200 Boiler. Huge pumps to the upper floors of the main building and indirect, and an alpha pump to the basement baseboards. I indend to use another alpha pump for the carriage house, and in fact, went ahead and install the alpha pump on the piping at the boiler for this carriage house. (BTW the supply/return 1” pex we buried is super super insulated, along with the 3/4” domestic water pipe. It takes about 2-3 minutes for the water to get hot in the carriage house, but it stays hot if you just use the water on and off, but I installed a circ pump for that.) Can you describe the flow switch set up where a thermostatic valve on the radiator would trigger a flow switch that in turn tiggers the Taco zone control to activate the pump? that seems like a good idea! The other three heating zones are triggered by a smart Wi-Fi enabled thermostat that I can control on an iPhone app. Sensi. Which has been terrific, but of course, requires thermostat wiring with a C wire. If there is another way to activate the system, I’d like to hear.

Thanks for this help.

RobinInCali

Please direct me to this flow switch set up. I used a flow switch once years ago on another heating system, and I can’t remember how it worked….

delcrossv

I think whats described above would be a thermostat in the coach house that would control a pump there. NoTRV. Flow switch would be wired into your Taco control like another zone (faux thermostat).

So coach house thermostat triggers the pump in the coach house, running pump triggers the flow switch in the main building, flow switch fires the boiler.