Location of indoor sensor for outdoor reset system

semma

Hello all,
I have been upgrading an old 1992 radiant system with a new Viega Basic Outdoor Reset control which uses indoor, outdoor, and supply temp sensors. The original design had an indoor sensor located centrally in the middle of the house, in a great room, in an open concept layout. There are two open loops for the great room on a manifold that has zone controllers for other areas. The great room has a two story windo wall and is centrally located in the first floor. I am thinking of moving the indoor sensor to the master bedroom wing which appears to be the highest heat loss room. It has a 12 foot tall, 8 foot wide window and has three walls exposed to the outside. The temperature in this room varies the most and can never quite seem to keep up in very cold weather. It's always three or four degrees short of target air temp. The room is tight. The master bedroom has two loops and I will move the zone valve actuators to the great room loops, swap the sensor for the stat in the master bedroom. My feeling is that the supply water temp isn't hot enough, fast enought, for the heat loss. My odr. Is set to a design water temp of 145f max 150f, design temp of 15f in cold weather, I frequently see 140-150f at the mixing station and 135-140f at the manifold. Do you think I am on the right track?
Thanks!
Sal

kcopp

It is worth a try. Sometimes you need to experiment w trial and error.

bmwpowere36m3

You could put the sensor in that room or increase the supply temps. Depends on how the system is laid out and zoned.

Mark Eatherton

Typically, European designs recommend that the indoor sensor be located in the worst case scenario heat loss zone. This is the "reference" zone, so yes, you are headed in the right direction.
Reference zones, as you noted, do not normally have a flow control device on their hydronic circuits (constant flow).

You may need to readjust your reset once you move the sensor.

ME

semma

Thanks all,
Today, I rewired these zones and moved the zone actuators. I will report back on the results. We have a 60 degree day heading to northern Massachusetts tomorrow and colder weather next week. So far, indoor temps have been within two degrees of set temperatures, but the temp curve has been a moving target this year.