Is a mixing valve nessesary?

[The_Hun]

I am in the process of hooking up my natural gas HTP boiler, I was wondering what the consensus was on putting a mixing valve in to regulate the temperature entering the boiler. Is it nessesary and what are the advantages and disadvantages to it? Thanks.

 

[anthony666]

I am in the process of hooking up my natural gas HTP boiler, I was wondering what the consensus was on putting a mixing valve in to regulate the temperature entering the boiler. Is it nessesary and what are the advantages and disadvantages to it? Thanks.

mixing valves aren't used to regulate temperature going into your boiler .. they regulate the temperature going into the floor .. we use them when the output temperature of the boiler is not adjustable & is too high for the slab or the floor covering selected, or when there are multiple temperature requirements for a system, for example, if you had an air handler that requires 150 degrees input and a slab that needed 120 .. its works by taking some of the water that's already been through the slab, and therefore cooler & mixing it with the hot water from the boiler, hence 'mixing' valve

they typically have a screened gasket because they're very susceptible to crud and old glycol can gum them up .. often a cause of hydronic headaches

you don't need one

 

[ket-tek]

If you decide you do need one, I have an extra one for sale..

http://www.garagejournal.com/forum/showthread.php?t=216891

 

[The_Hun]

Thanks Anthony, I guess I will not bother to put the mixing valve in my setup if it's not needed. I wish in the boiler instruction manual it would have more setups to follow. Appreciate the help

 

[anthony666]

anytime

 

[koditten]

When you are referring to "mixing valve" are referring to the automatic versions, or just a gate valve that you can use to adjust your temps of your primary and secondary loops?

My hi temp boiler uses a manual gate valve and it seems to work just fine. The water circulating around the boiler stays at or near 140*f and my loop or zone to my floor is kept at or near 105*f.

I would like to know more about the boiler. Is this a hi temperature boiler? If so you need to keep the temps in and out of the boiler elevated to keep any condensation issues in check.