Mixing valve for radiant-baseboard combo

Dave_16

I have inherited a hot water heating system where the previous owner added a (staple-up, under-floor) radiant loop on to a baseboard system via it's own circulator. To get the temp down to 120F, he used a 1-inch manual mixing valve on the radiant return line. The boiler is new, with outdoor reset, so it generates up to 190F water. So far, the manual valve works nicely as long as I check the temperature gauge on the radiant loop every couple of weeks, although I haven't yet had to change it since I got it dialed in to 120.

However (surprise, surprise) I don't the guy installed it right, because it leaks almost constantly and he globbed on a ton of thread sealant on. It threads on to some sort of copper sweat-to-thread fittings - looks like NPT, but I can't tell yet.

So, before I replace it and install it correctly, should I consider an automatic valve with a temperature feedback controller? Like I said, so far I seem to be able to control it to 120F - but I'm not sure about transient temps, whether it heats up fast or not.

BobM.

mix vlv

Mixing valves work very well with radiant heat. The leaks might be that the home owner left out the gaskets between the valve and tne cop x ips fittings. ??