Mixing valves and gypcrete

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
  • Super Cedar firestarters 30% discount Use code Hearth2024 Click here
Status
Not open for further replies.

SteveJ

Member
Hearth Supporter
Nov 19, 2007
221
CO 9000ft
With radiant floors using gypcre under carpet and hardwood floors, how important is it to keep the water temp entering the floor around 110?

What happens with a higher temp?

I currently have the water going straight from the wood boiler in series with a propane boiler going into the floor - temps around 170F.

For efficiency and power consumption, would it be best to use a mixing valve (tempering) or to use four way mixing with another circulator?

Eric - you mentioned four way mixing in this thread. Could you provide a quick diagram or detailed description? Would it be something like this?

Thanks,
Steve
 
That looks like a 3-way valve, but it's too early in the morning for me to focus on the details, especially since my understanding is a big hazy to begin with.

Craig told me about 4-way mixing valves. Here's my basic understanding, though I've never used one. Funny thing about that webpage: They say to oversize the valve by one size, but a heating pro told me to undersize a 4-way valve by one size to keep it from "hunting."

Anyway, as I understand it, 4-way valves work best on big zones with continuous circulation. A thermostat on that zone constantly adjusts the valve to maintain a water temp in the baseboards or floor radiant or cast iron radiators, etc. that keeps the living space at the desired temp. So instead of pumping 180-degree water into the house radiant periodically to keep the temp within the range, the four-way valve keeps, say, 130-degree water circulating through the zone at all times to maintain room temp. As the outside temps drop, the valve creeps open a little more, allowing the temp in the circulating water to rise accordingly.

The results, as I understand it, are twofold: First, you get more consistent, even heating and your radiators are always warm enough--but not too warm--to keep the house at the set temp. Secondly, especially with zones with big water capacities, such as those with cast iron radiators, you can store more heat, because it's spreading it throughout the system and maintaining it. It's no substitute for a storage tank, but it does allow you to keep more heat in your system than a conventional "bang, bang" arrangement.

Four way valves are big in Europe. When I was pricing them, you could get a new Honeywell 1 1/4-inch 4-way mixing valve for around $100 (valve body and actuator) plus another $100 or so for the thermostat. You can also use an outdoor stat with these valves.

That's about all I know. You'd probably want to get someone like Craig, who really understands the topic, to correct or elaborate on what I've said.
 
Eric,

Thanks for the info and thanks for sugar coating RTFM ;-)

Steve
 
SteveJ said:
Eric,

Thanks for the info and thanks for sugar coating RTFM ;-)

Steve

It's one of the many services we provide.

BTW, in this business, I've found that most of the FMs are NFG.
 
Status
Not open for further replies.