Tankless aquastat

keith123

If repurposing a tankless coil on a steam boiler for space heating, which a Honeywell aquastat would you use

mikeg2015

I used a RANCO digital aquastat on my tankless and I’m pretty happy with it. You get adjustable differentials and it displays the current temperature. Also used one for my DHW recirculation pump.

It was cheaper than most of the aquastats too.

Otherwise I’d use one with an adjustable differential.

Ron Jr._3

Space heating , meaning the coil will run a separate zone ?

I'd use a triple aquastat type if that's the case. We've been using the Hydrolevel 3450 with very little issues. You might need to add an isoltation relay to it to run with the steam zone too

keith123

Separate heating zone is correct

EdTheHeaterMan

L6006 or L4006 in the aquastat tapping on the coil. Set at 180 or lower. This will keep the boiler from steaming on a call from the hydronic coil zone.

set up the circulator relay as indicated in the diagram



1 and 2 are L1 and L2 or common

T T is from the zone thermostat
jump 1 to 3

power circulator with 4 (power) and 2 (L2 or common)

keith123

Thank you sooo much !!