Part 9187231 in the continuing saga, last post here
https://forum.mrmoneymustache.com/do-it-yourself-forum!/hydronic-heating-update-and-request-for-sanity-check/msg2168077/#msg2168077Brief recap: I have a single-room hydronic heat system for a converted garage. The PEX, baked into the concrete, only holds about 5 gallons of water. I need to heat up 5, circulating gallons of water. As an added catch, I only have a 120V, 15A circuit available at the place where I can add a heater. This system used to work when it was open looped through the house's water heater, but when I bought it the inspector told me this is quite unorthodox and I agreed, so it was disconnected before we bought the house and we replaced the main water heater for the house. I would later discover a lot of gross gunk in the water of the hydronic system, which confirms I made the right choice, and decided to redo the system with a separate, dedicated heat source.
I selected this Aquapower AQM 2-1 tankless, point-of-use water heater for the heat source:
https://www.homedepot.com/p/AquaPower-120-Volt-1-8-kW-0-27-GPM-Compact-Point-of-Use-Tankless-Electric-Water-Heater-AQM-2-1/206642687because my rough mental estimate was that it should work.
Frustratingly, it almost works. It heats the water in the system up to about 70 degrees (I'm in the Pacific Northwest, so that's more than the ambient temperature) and then it stops climbing. It's not enough to change the temperature in the room.
The problem is that the machine is configured to output water between 90-100 max, and then it stops increasing it above that. That is, the water gets put out at 90-something degrees and then by the time it circulates back, it's dropped to about 70 degrees. I looked more closely at the box and manual and it seems very much like it does this on purpose, and that it's not configurable by the user.
So, I need to replace my heat source. Any thoughts on what I could use here?
Again, the whole system only circulates 5 gallons of water. Given the fact that I can use an electric kettle to boil a liter of water for tea in a minute or two, this seems like it should be possible. I feel like the AQM 2-1 would have worked if not for a specific configured safety limit.
Product recommendations for what to use here? :)