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[caper]

does anyone else manipulate your heat, only -3 right now,however we are getting a cold front tonight and tomorrow -25 with wind chill, so im gonna put on my radiant heat now,usually takes 4-5 hrs before zone shuts off, however, then all my slabs will be warm and the boiler wont be working that hard when its -25...usually helps a lot when the temps are frezzzzzzzzn and wood last longer through the night....

[LittleJohn]

I typicall play with pump speed.  I have an Grundfor Alpha and it runs fine in Auto-Adapt mode, unless its going to be below 0F for more than a day or two, I cahnge it to constant pressure and its ale to keep up.

Ran in to an issue last year when outside temps were -20s & -30s for a week straight, the house woudl loose about 1 degree a day, which is not too bad but after a few days it was getting a little TOO refreshing in the house. 

[aries9245]

How often are your temps that low? We normally only get a few days a yr that temps fall below 0 but the past 2 yrs they seem to be more often it's crazy cold ..

[LittleJohn]

How often are your temps that low? We normally only get a few days a yr that temps fall below 0 but the past 2 yrs they seem to be more often it's crazy cold ..

It was an unusual year, we had 10 straight days were the temperature were always below -20F; by end of that stretch the house was about 65, not the normal 70-72

**BTW the house is all in-slab (about 4ooo sf)

But I have noticed that if I leave the pump in constant pressure, versus Auto-Adapt, call for heat are as not as extended.

[aries9245]

Is the slab insulated? Is that we're your radiant is installed

[LittleJohn]

Yes, 4000 sf of heat slab, that is insulated (new contruction, ICF footing and 2" under slab with 6" walls fully insulated.

THERE WAS JUST A TON OF LOAD ON THE SYSTEM WHEN ITS -20 AND BELOW (something like 50 yards of cement, rough calculation on weigh of slab is about 100 tons) and the water was moving pretty slow with the auto-adapt on.  In constant pressure, the temp can right back up in about a day and a half and no problems since.  Also it was not an issue of the stove having enough BTUs, it was an issue of the pump between the FPHE and the radiant field was not pumping fast enough. I wan to say I was in the neighborhood of the delta of about 40f across, supply and return manifolds

[hoardac]

I turn up my mixing valve if it is going to be really cold. but I can turn up all my loops also if that does not do it.