How hot should water be in Radiant pipes?

DABegley

Under floor system.  Insulated from basement. PEX tubing stapled to joists, not to wood sub-floor.  Water temp in the pipes varies with outside temp from less than100 to 165.  That is the temp as it leaves the boiler, temp is likely lower when it hits the pex tubing as it flows through anywhere from 20 to 40 feet of copper tubing to get to the manifolds that feed the pex tubing.  The high end is when the outside temp is below zero.  I can grip and hold the pex tubing. at least for a bit, at it's hottest.  Normally it is less than120.  Is that too hot?  Thanks.

kcopp

in a staple...

up w/o plates generally the temps are in the 150-160 range. From your description I am surprised that the system works....or does it?

JPCCEM

Temp of Radiant Water

Just was involved in a design for a radiant floor design for the first time.  I'm not the expert here, but I did get a thorough briefing from a solid applications engineering rep for Upanor.

Key factor in the floor temperature is to not have too big of temperature gradiant in the floor that will cause the floor to warp, crack, or otherwise fail.  Generally, the temps are set up to allow a floor surface temperature of no more than 80 deg.  That generally translates to 130 deg water temp for hardwood. 

The good suppliers and reps can tell you the water temp for the type of floor.  It doesn't happen too often, but one of the more frequent failure modes for this type of system is to "collapse" the floor with water that is too hot.

JPCCEM

Temp of Radiant Water

Just was involved in a design for a radiant floor design for the first time.  I'm not the expert here, but I did get a thorough briefing from a solid applications engineering rep for Upanor.

Key factor in the floor temperature is to not have too big of temperature gradiant in the floor that will cause the floor to warp, crack, or otherwise fail.  Generally, the temps are set up to allow a floor surface temperature of no more than 80 deg.  That generally translates to 130 deg water temp for hardwood. 

The good suppliers and reps can tell you the water temp for the type of floor.  It doesn't happen too often, but one of the more frequent failure modes for this type of system is to "collapse" the floor with water that is too hot.