Thermostat for In-Floor Radiant Heat

Toby Karlquist

Can someone please advise me if there is a certain type of thermostat that is recommended for in floor heating systems? We have a 1450 Sq. Ft. home with a Crown Boiler (Model ABF-070 EID LP) and a single station for the entire house. The existing thermostat (a Lux T101141/PSM30) is centrally located in the middle of the house. We had a friend over who told us that he didn’t think we had the correct thermostat for in floor heat.

We are about to build a 450 sq. ft. addition and will be adding a 2nd station to our existing boiler and want to make sure that we get the correct thermostat.

Last winter was our first in this house (which was built in June 2001) and the heat worked great. I would ask our builder this question but it seems that he is far too busy to deal with one of his own customers.

Thanks in advance for any help/suggestions that you can offer!

Toby Karlquist

Pagosa Springs, Colorado

John Ruhnke1

Tekmar 510 or 511

Best radiant thermostat on the market!!

JR

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Gregg Jackson

The new Tekmar T-Stats are phenomenal

The only advice I would give, when choosing a thermostat for radiant, is to find one that is very accurate and has a low margin for error. This will reduce temperature swings. I do not know the exact differential on the new Tekmar but I am sure it is tight.

Gregg

BillW@honeywell

Stat

Take a look at the Honeywell PC8900. It controls temperature, humidification, system changeover, monitors filter on AC side, +-1 degree electronic accuracy. Optional telephone module allows access & monitoring from any touch tone phone. It can support up to 9 optional remote sensors in the house for more even temperature control. Lighted dial, outside air sensor, 7day programming, EPA EnergyStar rated product. If you don't have AC or humidification, take a look at the T8665A wireless programmable. It is a 7 day, battery powered stat with all the features you'd like. It requires no wires from the stat to the heating equipment, a receiver module that wires like any thermostat is located in your mechanical room. Visit the website for more information...

www.honeywell.com/yourhome/

These products are only available from your professional heating/cooling contractor.

Chris Maderia

Radiant Therm

For starters my feeling is that a Thermostat in a radiant application is uselesss. If the heat loss was done correctly and the system was designed correctly it has no bearing. The object with radiant is to provide maximum comfort by replacing a BTU for a BTU evenly keeeping your heating space at a continuous even temp while never satisfying that therm. Pretty much all therms offered by radiant manufactures are fine. You cannot use a typical Honeywell Therm for it has a differential of + or - 5 degrees while a radint therm's is + or - 1 degree.

BillW@honeywell

Stats

Hi, Chris. That's exactly why I suggested the PC8900 as the first choice. It is +- 1 degree accurate, and the remote sensors allow it to average among up to 9 remote inputs and the main "stat" itself. Older stats do have a wide differential, but the PC8900 and any of our new Chronotherm 4's are set to 1 cycle per hour for radiant. The use of a stat for radiant is controversial, and the Tekmar is a fine product. I suggested the PC8900 since it controls all hvac functions from one control.

Tim

honeywell Tstat

Hi Bill, I have a model home going in 'Could use a couple demos they sound awesome. What is the price of dem der stats? They also sound expensive. I will check the out.
Tim

Chris Maderia

No Therm is the best Therm

Since we are not heating the air in a radiant application and assuming the heat loss of the bldg is accurate are goal is to replace a btu for a btu providing max comfort. I have about 2 dozens systems running without therms. My heat source for these systems are Buderus, Viessmann and they work totally on warm weather shut down, out door reset, and mod mixing vlvs with continuous circulation. There are no swithcing relays either for the circs. They are all wire in series with my primary loop pump through either boiler manufacuters control.

The key to this design is heatloss accuracy, system balance and loop & maifold design. I cannot stress enough about heat loss and design accuracy.

Tim

Human BTUs

Chris
What do you do when you fill a room with people and the outdoor temp is calling for heat. I feel the tstats are good for high limit switches. The honey well unit could be used for high limit and A/C.
Tim

jpatterson

tstats for radiant

we have had great luck with the Erie T201 (heat onlY) and PSG makes a heat only also