radiant adjustment

losthope

the first floor of my home is radiant that is controlled by an taco i valve. how do you guys setup water temp? do i set it up with the lowest possible water temperature that will still heat the house(longer circulation time)?... or do i turn the water temp up a little to shorten circulation/run time?

kpc_59

the latter...

get er done asap.

losthope

so i will use less oil with hotter water temps?

losthope

do i turn it up, as long as it doesnt heat the house past the thermostat set point?

Rich L.

Minimum temp to heat the space

I disagree with KPC. I set up all my radiant jobs with the lowest possible water temps that will heat the space to the desired temperature. I ALWAYS recommend outdoor reset to automatically accomplish this.

Radiant is not like forced air. You don't want to see temperature swings with the unit cycling on and off. The general philosophy with radiant that I use is lowest water temps that will allow the circ pumps to operate for the longest periods possible.

Think of it this way. If you run higher water temps, you heat up the space and the floor cycles off. Now the floor cools off even though the space temp is ok. Now we have a cool floor and that generally is acompanied by an unhappy customer that thought this radiant stuff was always going to mean "toasty warm floors". It's the opposite of what you usually want.

Lower water temps, longer cycle times, more comfortable floors.

Rich L.

Less oil

You COULD wind up using less oil because you're not putting as much heat/ energy into the water to get the higher temps.

jp_2

maybe, maybe not

depends on if your boiler is set up to be able to run the load for long periods without short cycling or cycling on high limit.

losthope

ya the Ivalve i have has outdoor reset. and my aquastat has a high limit differential of 30 degrees so short cycling isnt a problem. any other thoughts?

kpc_62

need more info.

it need to heat the space in a reasonable amount of time... if it takes 6 hours to raise it 2 degrees that will not save you much. What are the numbers? what is the application? staple up ? slab? plates? no plates? are we talking 140 design temps or 90? I have used the I valve a number of times. it gives you a number of options and choses depending on the boiler and design....