Reset Question

J.Prisby

Wirsbo's ProMix 311 control. It can reset and control your High Temp Boiler/Joist System and give you the Mix Temp Control/Reset to keep your Slab System in check. The 311 also gives you the option to control a DHW Tank all in the same Box.

J.Prisby

JimmyJam

Reset Question

I will be installing a two temp radiant heating system (low temp slab and higher temp joist) and will be using a Munchkin 80M. My question is what outdoor reset stategy should I propose? I have only installed a handful of resets and all are Wirsbo 201 duomix injection systems. To accomplish outdoor reset with the Munchkin is there a way to reset without injection?

Thanks for any help!

Jim

Ken Wickre_6

tekmar 363

Not being familiar with your system as designed or the Munchkin boiler, I propose this as something to investigate. You know you need two temperatures, say 100°F at the slab and 160°F at the joist; which means you will have to reduce and regulate the lower temperture requirement anyway. If you select the tekmar 363 (an injection mixing control), it will provide boiler reset (for the high temperature side) and mixing reset (for the low temperature side). Each system is monitored and controlled individually from each other (and DHW control is available if desired).

Another option would be to consider a single boiler reset, such as a tekmar 256, to reset the boiler side which the joist heating is connected to. Then utilize proportional reset as described in Modern Hydronic Heating by John Siegenthaler. This is simply a manually adjusted primary-secondary pumping arrangement eliminating fixed temperture mixing valves, controlled mixing valves, or injection systems. The reset water temperature is "proportionally" transfered to the lower temperature side.

I would lean towards the 363 for these reasons: It is simple and quick to set up; it offers excellent control; it provides each side with its own reset curve for comfort and efficiency; and your involvement after installation and start-up is minimized.

kf_2

reset...

don't use an injection pump for reset on a condensing boiler, it will elevate the water temp back to the boiler. Use a control that will reset the boiler only, and use 3-way manual or motorized mixing valves. Do not use 4-way valves.

kf

tim from Reed Wright

reset of munchking, I agree, use a tekmar 260 control and a manual mix valve for lower temp slab. I have the same scenario I am working with right now and trying to correct all the mistakes made by others.