Four-way mixing valve circulator question

Eric Johnson

Note: This is lifted from a thread I tried (and failed) to hijack. If it's an inappropriate question for this forum, please let me know.

I have a hot water system with four (pumped) zones, one of which has 11 ci radiators on it (the original house, circa 1865). The other 3 zones, serving additions, have 2 ci rads each. I'm thinking about putting a four-way mixing valve on the big zone and running the circulator (Grundfos 20-42) 24/7. I think it's possible to regulate the mixing valve with the thermostat that currently controls the circulator, though I'd certainly put in a dedicated stat if that made more sense. My primary heat source is a wood-fired boiler, with a separate gas boiler for backup.

Is it that simple, or are there other considerations I need to take into account?

I'd like to do this for a couple of reasons. First, I've heard that it's a better way to heat a house, with more even heat, greater responsiveness and less wear & tear on the circulator. Plus, I'd like to use the large amount of water in the system for heat storage from the wood-fired (gasification) boiler.

Bill_17

4-way mixing valve question

Motorized 4-way valves are power to open and power to close, so you will need more than just a standard 2 wire thermostat that closes a switch on a call for heat. Any 4-way valve supplier should be able to suggest several thermostats that will meet your needs.

Eric Johnson

Thanks Bill

I see that Honeywell has a valve, motor and stat all matched to each other. Presumably Taco and other mfgr have similar offerings.

Is it safe to assume that if the zone works fine with a room stat/circulator arrangement that the same zone would work with a four-way valve and constant circulation?