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outdoor reset with conventional boiler multi-tem

Brad White
Brad White Member Posts: 2,398
Instead, ask yourself, "What is the advantage of running a higher temperature for the high temperature zones and not maximizing efficiency to the extent that the boiler can tolerate it?"

You certainly can and should use ODR on your high temperature emitters and still be high enough to govern your low temperature radiant areas.

The notion of ODR in radiant has more variables such as mass (recovery time) and the type of floor application (staple-up takes higher temperatures than thin-slab or sub-floor plates for example).

If you run your floor as a baseline with limits to monitor and maintain floor temperature with anticipation, you could still use ODR to a degree. That depends on how good your controls are at responding to changes ahead of the curve.

Another facet of ODR with radiant is that you are already probably running relatively low water temperatures (maybe, maybe not), so there is not a whole lot of range of motion.

The other side is, once warmed, it takes very little adjustment to maintain it.

Bottom line: I would use ODR on the higher temperature side first ("where the fuel is burned") and then tweak the radiant side to the extent that your controls allow.
"If you do not know the answer, say, "I do not know the answer", and you will be correct!"

-Ernie White, my Dad


  • NRTDave
    NRTDave Member Posts: 48

    What is saved by using outdoor reset and a electronically controlled mixing valve for radiant floors under wood in the case of a conventional boiler which is serving other high-temperature (radiators) zones?

    Outdoor reset makes sense to me if it allows you to lower the overall water temperature of the system, but if it is just tied to a mixing valve I don't understand the advantage.

    I guess the flow would be more continuous since the water temperature could be lower during periods of low demand. But would there be any efficiency advantage if you have to mix it down from the higher temperature?


  • [Deleted User]


    I have a staple system. Temp supply to the manifold is about 115-120 degs. Is there less of a benefit of ODR with radiant floors? I planning on replacing a 50 yr old boiler w/ a 3 pass CI boiler. ODR adds about $400 to the install price. Is there less of a payback when the system is running at lower temps to begin with?
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