Radiant Heat Balancing Issue

NoSmoke · Post by **NoSmoke** » Sun. Nov. 23, 2014 8:11 am

I have an interesting problem that I cannot seem to figure out, my radiant floor heating system...within a concrete slab...is unable to heat my house to the desired settings of 70 degrees...despite having done so well for the last 8 years.

The boiler is cycling as it should and producing 100-150 degree water on the main loop

No circulators are burned out

The mixing valve is delivering the desired temperature to the floor that the system calls for based on the temperature sensor outside

The temp sensor outside is functioning and accurate

The Thermostats in the various zones are accurate and working and kicking on the zone valves

The temperature drop from the water going into the floor to what is returning is at the proper 15 degree drop

None of the flow controls are broken and are adjustable (currently set for 1/4 gpm flow to get said 15 degree drop in each loop)

In short it seems I have a perfectly functioning system that just does not seem to be able to keep my well insulated and new home warm whether it is 11 degrees outside or 36. It is a constant 66 degrees inside when the thermostats are set at 70. What am I missing and why did it work fine the last 8 years and this year it cannot maintain the desired temp?

Can anyone help me figure out what is amiss?

scoobydoo · Post by **scoobydoo** » Sun. Nov. 23, 2014 8:17 am

Did you do any air sealing to the house this summer?

NoSmoke · Post by **NoSmoke** » Sun. Nov. 23, 2014 8:49 am

No we didn't.

Pauliewog · Post by **Pauliewog** » Sun. Nov. 23, 2014 9:03 am

If you set your room temperature to 75 degrees .... does the temperature rise over 66 degrees?
Paul

titleist1 · Post by **titleist1** » Sun. Nov. 23, 2014 9:09 am

Do the thermostats seem to be 'satisfied' with the room temp of 66*?

The reason I ask is that you say the thermostats are 'accurate and kicking on the zone valves' which doesn't sound correct if they are set to 70* and the room is only getting to 66*. Shouldn't the zone valves always be open if the temp is below 70*? What would cause them to close if the temp isn't 70*?

I'm not a boiler guy but that didn't seem right to me?

Pauliewog · Post by **Pauliewog** » Sun. Nov. 23, 2014 9:39 am

titleist1 wrote:Do the thermostats seem to be 'satisfied' with the room temp of 66*?

The reason I ask is that you say the thermostats are 'accurate and kicking on the zone valves' which doesn't sound correct if they are set to 70* and the room is only getting to 66*. Shouldn't the zone valves always be open if the temp is below 70*? What would cause them to close if the temp isn't 70*?

I'm not a boiler guy but that didn't seem right to me?

That is the same direction I was heading. If the system maintains a constant 66 degrees regardless of the outside temp......... it sounds like the zone valves are closing .
Are your thermostats satisfied at 66 degreesm
Paul

waldo lemieux · Post by **waldo lemieux** » Sun. Nov. 23, 2014 10:15 am

Are the floor loops full of air?

windyhill4.2 · Post by **windyhill4.2** » Sun. Nov. 23, 2014 5:42 pm

Set the thermostat to 74* & see if you get the desired 70*.Keep It Sensibly Simple,start with the easy things & work toward the complicated.

NoSmoke · Post by **NoSmoke** » Sun. Nov. 23, 2014 5:54 pm

titleist1 wrote:Do the thermostats seem to be 'satisfied' with the room temp of 66*?

The reason I ask is that you say the thermostats are 'accurate and kicking on the zone valves' which doesn't sound correct if they are set to 70* and the room is only getting to 66*. Shouldn't the zone valves always be open if the temp is below 70*? What would cause them to close if the temp isn't 70*?

I'm not a boiler guy but that didn't seem right to me?

Sorry, bad wording on my part. I meant when you turn the thermostats to "on" they open up the zone valve. In an attempt to economize words, I confused you. (These technical issues can get wordy when you try to explain every detail of what is happening).

Today the zones got up pat 70 degrees due to it being warm outside, and the sun shining through the windows so I heard the thermostats shutting off. What I am wondering is, I just turned the radiant floor heat on starting Monday night (11/17/2014) and it only reached 66 degrees inside by Friday (11/21/2014). By Wednesday you could feel the floor warming up, but I am wondering if it took longer for the radiant aspect of this type of heat to warm the objects in the room as well as the woodwork and stuff.

???

NoSmoke · Post by **NoSmoke** » Sun. Nov. 23, 2014 6:01 pm

BTW: Funny little thing happened during all of this. You guys know me, I am CHEAP so I wait until the last possible day to turn on my heat. Some days we got up and it was 51 degrees in the house and 16 degrees outside. After enduring a few showers where I stepped out onto an ice cold floor, I still held out...after all, every day a person can wait is just one day closer to Spring when you can shut your heat off.

Every man has his breaking point though, and mine happens to be my wife who got tired of wrapping the baby in 20 blankets and having her teeth chatter when our daughter woke up. So I turned the heat on...and yes 66 degrees is better then 51, but now the temp is suppose to go up to 50 degrees outside for the rest of the week!! If I had only waited I could have shaved another 10 days off my heating season!!

I cannot win!