Radiant Floor Heat- Circulator Runs too much?

Cyclist77

I will start by saying I read an older discussion where the fellow was wanting a system where the circulator runs continuously.

My circulator, for the main living area, tends to run almost continuously. Even now as I write this the room and my feet are very comfortable. But the circulator is running. I think my "problem " might be the type of thermostat. It is not sensing the floor temp just the air.

Am I on the correct though process?

kcopp

No. I think you are over thinking this.

If it works dont mess w/ it.

LRCCBJ

If a radiant system can hold room temperature on these quite cold days, the occupant should be extraordinarily pleased. Your circulator is running continuously because every bit of energy is used to maintain temperature. If you don't want it to run continuously, just lower the thermostat to 60 F. It will stop!

Cyclist77

I hear what you are saying but my brain is not cooperating! Maybe more coffee is required!

It seems to me if the floor is comfortable the circulator could be turn off. This is why the floor sensor type thermostat is interesting.

LRCCBJ

If the floor is comfortable, turn the 'stat down by 1 degree. Try it for 24 hours.

The circulator WILL shutoff if the ambient temperature climbs a bit.

DCContrarian

I never understood the logic of floor temperature sensors.

The output of the floor is entirely determined by the temperature difference between the surface of the floor and the air in the room. You want the output of the floor to vary depending on the heating load. You don't want the room temperature to vary. The only way that is possible is if the floor temperature varies.

You can vary the floor temperature by varying the water temperature or the flow rate. The flow rate can be varied by varying the duty cycle of the circulator, or its speed. Without knowing what else is going on, a high duty cycle is not by itself reason for concern.

Even with no temperature modulation or speed modulation, the duty cycle should approach 100% as the outside temperature approaches the design temperature.

psb75

This is why we now use ECM circulators. Constant circulation—not "bang" ON, "bang" OFF. This is commonly referred to as "Bang Bang" technology and is old-fashioned. It is certainly and largely associated with "scorched air" heating systems. It is really good if your slab loses no more than 1 or 2 degrees on the T-stat once it is up to the desired "air" or "slab" temperature.

hot_rod

with a common ECM type circ you are looking at 7- 40w, so it is not expensive to let them run.

The floor temperature stays consistent, and any solar gain will be moved throughout the entire system.

I use floor sensor in bathroom zones. So in summer months, even with AC running you could maintain a warm floor. Either set it as a not to exceed temperature or not to drop below.

They can be useful in snowmelts also

bjohnhy

https://forum.heatinghelp.com/discussion/200456/radiant-floor-heat-circulator-runs-too-much

I don't see a problem. Floor sensor is not needed IMHO.

Does your system use Outdoor Reset to vary supply water temp?

Jamie Hall

In an ideal floor radiant system, the circulator will run constantly. An outdoor reset will be used to vary the circulating water temperature as needed, with a room temperature sensor to trim the water temperature. How that is accomplished varies with the system — but in any case the floor circuits are running all the time.