outside resets and other gadgets

Ken B

I have a 3200sq ft home in NY. I am planning on a retrofitting my oil burner to a high-efficiency setup, and adding one radiant floor zone, and an indirect DHW unit to my existing 3 baseboard zones.
I’m leaning towards a locally available Biasi B10 and Vaughn Red Jacket indirect water heater. I thought I’d be able to let the boiler drop down to room temperature until a zone or the DHW unit called for heat. But after reading about flue gas condensing issues due to boiler temperatures lower than 140F, I’m beginning to wonder how much I’m really saving if I still have to maintain a low limit as “high” as 140F. Is there something I’m missing?
Also, I looked at the Tekmar Boiler Control 260 as some internet browsing had me interested in an outside reset control for further savings, but I’m not sure I’m a candidate for one. Will the unit be able to recognize that my 3 zones, my DHW, and my radiant floor all have different ideas about the ideal temperature?
Would adding a mixing valve to warm the return loop help at all, and if so, can someone recommend a part number?
Homeowner here, as if you couldn’t tell.

Robert O'Brien

I

use the Biasi extensively and have never had any condensation problems in the boiler,the period of time spent operating below condensing point in a cold-start application with a low volume system with DHW is not great. High volume systems will require a bypass.You will need a mixing valve for the radiant zone. The 260 will not control a mixing valve,you would need a control that would control a reset mixed temp,DHW and reset boiler temp. A 363, I think would fit the bill.

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J.C.A._3

I'm thinking...

System by-pass. Taco pc700 and an a 3 way i-radiant valve for the radiant zone.

The i-radiant will give you the outdoor reset for the radiant zone, and the pc700 will control the DHW supply and outdoor reset for the rest of the system. The by-pass will keep an oil fired boiler from condensing.

Simple and effective. I'm not sure about cost point but I'd bet it will be less than a mixer and all the related "accutriments" associated with anything else. JMHO. (I've been known to be wrong before). Chris

brucewo1b

JCA Can you remember the last

time you were wrong except according to the wife. Said with tongue firmly planted in cheek.