Infloor heat set-up

[ketas47]

Just started my system Thurs. for my 26x38x10 fully insulated garage.Use a lochinvar copper fin non-condensing, 84% eff. boiler.(45000btu).Use a ball valve to recirculate water to boiler. I have a heat exchanger(fan off) before water goes to floor to lower my water temp.(drops about 30 degrees). Also can shut-off water going into floor and just run through heat exchanger and turn fan on to warm up garage quickly if needed. I leave pump on all the time to get all the heat into floor(was told it cost about $20 to run pump for the season).When boiler starts up water is approx. 60*, as boiler water temp comes up return water is approx. 20*-30* cooler. Takes about 8-10 min. to get return water to 125-135* range.Then boiler settles out to about 150-160* going out to 135-145*return. Runs for about 10 min more before room thermostat shuts down boiler(Total 16-23 min cycle).(Water going into floor starts @ 60* and goes as high as 120*by the time boiler stops.) Boiler runs every 2-4 hours depending on outside temp.I know the return temp should probably come up quicker so I dont possible harm boiler but during the warm up time the boiler is running most eff.( paid $200 for boiler) When and if boiler fails I plan on buying condensing boiler. This was fairly cheap route! Comments are appreciated. THANKS P.S. Live in central Wi.

 

[thooks]

1. Use the return/enter key for some paragraph breaks. Thanks.

2. If the 150 to 160F leaving water temperature is 120F in the floor, you are losing some serious heat to something. It should be within 2 degrees entering the floor as leaving the boiler...with proper insulation. Yes, a 20 degree delta T from the leaving to return temp is good. You should be leaving the boiler at 120F or so and coming back at 100F.

You want a lower hot water temp for in-floor heating than normal boiler/hot water heating operation (180-160F).

 

[VairKing]

You want a lower hot water temp for in-floor heating than normal boiler/hot water heating operation (180-160F).

Whats the rhyme and reason for this? Efficiency? It seems to me if it got the floor hotter than necessary the extra heat would make the room warmer therefor delaying the time until the next cycle. (a good thing I think?) I have no knowledge in this area but am learning more everyday!

 

[CARS]

My boiler's high limit is 180 because I have rads and exchangers

BUT, I temper the in-floor to enter at 110 and my return is about 100-105.

I was warned about heating the floor too hot. So treat the in-floor as a separate system from my rads/exchangers which need a hotter boiler.

 

[ketas47]

I am keeping my water going into the floor 120 or lower, Im running the hot boiler water through the (Dayton) heat exchanger before the floor to drop the temp so it is not to hot when it enters the floor and the heat from my exchanger is going into the air, so not really losing any energy? I am mixing the out going water with the return to try to keep a 20 degree difference. I cant run a Non Condensing boiler very long without having a return temp 135- 140 without doing damage to my boiler. So I cant set my boiler @ 110 and return it at 90

 

[CARS]

I am keeping my water going into the floor 120 or lower, Im running the hot boiler water through the (Dayton) heat exchanger before the floor to drop the temp so it is not to hot when it enters the floor and the heat from my exchanger is going into the air, so not really losing any energy? I am mixing the out going water with the return to try to keep a 20 degree difference. I cant run a Non Condensing boiler very long without having a return temp 135- 140 without doing damage to my boiler. So I cant set my boiler @ 110 and return it at 90

I got the lowering of temp through the exchanger, but what makes you think it is the same every time. Are you running the exchanger everytime the floor calls for heat?? If so your slab is never really going to get "saturated" and actually radiate heat. I just use mine when I need a quick heat after my booth ***** all the hear out of the shop.

Are you running a "hot" boiler?

 

[thooks]

I think you need to run a constant temp through the floor (120°F) and a higher temp through the fan coil (180°F).

You probably need a primary/secondary pumping system for this with 3-way valves.

 

[sneezer41]

Primary Secondary piping would be great for your system.

I do not think you are hurting your boiler as long as it does come up to temp during the cycle[and thus boils off the condensation]

If the system is doing what you want, it does not sound too bad.

Yes you should run cooler water through the slab

 

[thooks]

Whats the rhyme and reason for this? Efficiency? It seems to me if it got the floor hotter than necessary the extra heat would make the room warmer therefor delaying the time until the next cycle. (a good thing I think?) I have no knowledge in this area but am learning more everyday!

You want more of a low-n-slow, constant heat sink in the in-floor heating systems, not a HOT floor that cools and re-heats.

You want about a 95°F floor temp that stays that way during the heating season.


I will admit I love his setup of having in-floor heating and a hot water fan coil. The best of both worlds. It's just got to be done right.

 

[VairKing]

I use a wood boiler to heat my house and shop. I have been using boiler temperature water (160ish) to heat the floor in the shop. I have no idea how to lower the water temp just in the shop, as I need 160 water for the heat exchanger in my house. Thoughts?

 

[swvega]

I've been told that if you run that kind of temp in the floor it will destroy your concrete. Makes it fall apart. Temp of floor should stay about 80-90.

 

[CARS]

I use a wood boiler to heat my house and shop. I have been using boiler temperature water (160ish) to heat the floor in the shop. I have no idea how to lower the water temp just in the shop, as I need 160 water for the heat exchanger in my house. Thoughts?

The valve (the name escapes me) that is on the branch that feeds my in-floor system is alot like your faucet/shower at home. It takes as much of the boiler's water as needed and mixes in return water to keep a certain temp.
Mixing hot and cold basically.

 

[CARS]

I guess it's just called a mixing valve... lol
Thought it was something more elaborate!

http://www.pexsupply.com/Watts-Thermostatic-Mixing-Valves-609000

 

[VairKing]

I will install one! Don't want to wreck anything! I will plumb it so it mixes with cold returned water. I was confused how it lowered the temperature but now I see the light!