Setting up new NTI TFTN Boiler....

[spf8298]

We just installed a new NTI TFTN Boiler with a touch-screen interface. I have no faith that the contractor that installed it set it up correctly. When I logged into the interface, it was all set at factory defaults. We use the boiler for trough heat and floor heat and it is charged with glycol. Does anyone else have a boiler like this? If so, can you give me some input on how you have it programmed? I would guess that you want it set up as 'central heat' and not 'domestic hot water.' I'm particularly curious as to what outdoor temperature you have the boiler set to kick on at, and also what heating temps you have it set at for the glycol? I see a lot of guys have the outdoor temp set at 32-38 degrees and the boiler temp at 105 with an aquatstat set at 55-70 degrees. Hope I'm making sense. I'm learning as I go.

We do have an aqua stat on the incoming glycol line and also have an outdoor temp sensor on the north side of the building.

 

[soapy]

My floor heat boilers are set to 140 degrees both on my munchkin and Raypak boilers. I only kick mine at slab temperature sensors. I do not care how cold the air temp is just that no ice forms on the slabs.

 

[Rudy]

You want to set your circulator to start just (barely) above freezing...ie, 33F. Think of it this way, if it's 34F ALL day, do you want to spend a dime on gas or electricity when there can't be any icing?

We moved the "floor stat" to a "return stat" setup. The floor stat only senses only ONE particular spot on your floor. A return stat senses the temperature of the returning glycol from the entire slab. It should be more accurate.

If you go with the return stat, you'll have to play around with it, to determine what setting keeps the floor deiced. At our wash, 77-78F is the number that keeps the coldest area of concrete just above freezing.

 

[Eric H]

Check to make sure that the outdoor temp sensor is hooked up. Then call tech support and tell them you are using the boiler of ice melt.
I was lucky enough to get a tech support guy (at HTP) that understood what I was trying to do. He got the settings pretty close to what I needed.
I have my on temp set fairly low at 33
Degrees. You don’t want it running for no reason. My competitor’s boilers aren’t set up correctly. His boiler runs in the 40’s and heats the floor to mid 60 degrees. My floor temp is set to about 40 when it is running.

 

[2Biz]

If its not set right, you're wasting $$$$. Back when I upgraded to a wall type demand heater from the old dinasour 350k btu Jarco Boiler, I used the return temp of the glycol to control the pumps to the demand heater. I have the primary/secondary plumbing...With a variable/diferential aquastat on the return, it makes the whole system more adjustable. I have my aquastat set with a 15° differential (55°/70°) and 105° output on my demand heater. Output to the bays and trough is about 90°. Every system will be different based on circulator GPM and GPM output of the heater. The system and pumps are activated off the secondary output of the weepmiser at 32°. At 32° both bay circulator and circulator's to the demand heater turns on. The heater circulators cycle on/off 15minutes on/15minutes off. When it gets colder, the cycle automatically changes to take on the load. But ALWAYS has a 30 minute cycle. 0° the cycle is 20 minutes on 10 minutes off. Using an infrared gun when I initially set it up 10 years ago, I tried to get an average of 40° slab temp. I made minor adjustments the first winter, but easily dialed in the aquastat a few degrees either way to get the exact sweet spot to keep the bays ice free. I haven't adjusted the system since. One of the better modifications to wash that I made. Another valuable addition to the system, I installed inline switches to the pumps. My slabs will easily stay ice free as long as daytime temps are above 40 and night-time temps down to about 27°. The switches makes it easy to micro manage the system based on forcasted temps. Link below to learn more...

Tankless Water Heater For Floor Heat | Car Wash Forum

 

[GoBuckeyes]

I I have my aquastat set with a 15° differential (55°/70°) and 105° output on my demand heater. ...............The system and pumps are activated off the secondary output of the weepmiser at 32°. At 32° both bay circulator and circulator's to the demand heater turns on. The heater circulators cycle on/off 15minutes on/15minutes off. When it gets colder, the cycle automatically changes to take on the load. But ALWAYS has a 30 minute cycle. 0° the cycle is 20 minutes on 10 minutes off.

2Biz, just out of curiosity, what is this 30 minute timing cycle and what is dictating the percentage of on-time/off-time? I thought you were simply controlling flow to your heaters with the Aquastat once the system is powered up at 32F, flow to heaters at 55F until return temp reaches 70F?

 

[2Biz]

You are on the right track. With the aquastat (with Differential) on the return from the bay loops AND the ability to adjust temperature on the demand heater, you have an infinate amount of variables that control cycle (on/off) timing. I think I remember starting with a 5° differential and 140° heater outlet temperature. The heater short cycled which I didn't like...I then changed the differential to 10° and the cycle doubled in timing 10 minutes on, 10 minutes off. I settled on the 15° differential which powered on the heater pumps 15 minutes on/15 minutes off. It seemed to be directly proportional! I then found that 105° output on the heater was all I needed to keep the bay floors at roughly 40°. The colder it gets from 32°, the longer the On cycle is and the shorter the off cycle is, but is always a combination of 30 minutes. Even down to -16° (below Zero), it still cycles on and off, meaning I still have capacity to go on the heater at these settings and temperature. Even at -16°, it keeps the bays ice free. I have experimented and kept one bay open to this temp with weep flowing across the floor to the drain and it stayed ice free. Once I settled on the settings above, I don't have to adjust anything, it self regulates based on load. Hope this helps...

Every system is different based on pump/zone flow rates and heater flow rates. 105° on my Takagi 199kbtu with (2) Taco 013's feeding it in series at 40psi gives me 6gpm flow output on the heater. When you dial in more heat, say 140°, it restricts flow to about 4gpm to achieve the higher temperature and also modulates to a higher heat setting....So this will change all the dynamics. The single Taco 013 for my (4) bay loops and (1) trough loop is calculated at about 2 gpm flow rates for each loop, which is right in the sweet spot, according to all the documents I read. Flow rates of either the primary or secondary loops will affect the cycle timing and aslo how the loops transfer heat to the slab. Mine just happens to be most efficient at the settings stated above. I have helped others with a system similar to mine, even heating floor loops in the living space of their house along with driveway snow melt, all on the same system utilizing (2) demand heaters. Every project I've helped with seemed to be most efficient once dialed in to the 15 minutes on 15 minutes off cycles.

Here is a link that explains primary/secondary plumbing in case you don't know what it means:

Primary/Secondary plumbing | | DIY Radiant Floor Heating | Radiant Floor Company (radiantcompany.com)

 

[GoBuckeyes]

Thanks for the explanation 2biz. I finally got my hands dirty with a Takagi. I’m using two 199k units in parallel fed by two Taco 013’s in series to heat water held in a 120 gal storage tank. Units are set at 120F and my tank aquastat which controls the pumps is set at 115F. Have had it in service since November and so far so good.



I looked into using another HTK Phoenix but the prices have gone through the roof.

 

[MEP001]

I looked into using another HTK Phoenix but the prices have gone through the roof.

Looks good, you have the same storage and twice the recovery as an HTP Phoenix for about half the price.

Side note: The HTK Phoenix is a ship.

 

[2Biz]

Thanks for the explanation 2biz. I finally got my hands dirty with a Takagi. I’m using two 199k units in parallel fed by two Taco 013’s in series to heat water held in a 120 gal storage tank. Units are set at 120F and my tank aquastat which controls the pumps is set at 115F. Have had it in service since November and so far so good.

View attachment 7690

I looked into using another HTK Phoenix but the prices have gone through the roof.

Nice looking setup!! I considered doing the same with one heater to do both a storage tank and floor heat, but made more sense to split it up and go with the HTP for hot water....I'm glad I bought my HTP before the price hike! At todays prices, it would be way cheaper to do it the way you did, even with 2 Takagis!

 

[GoBuckeyes]

I have to say I was impressed with the Takagi’s today. Last night we lost power at the wash and the power company didn’t get us working again until about 10am. When I fired them up the incoming water temp was 37° and the output temp was 121° with a combined flow of 7 gpm.

2Biz would you change or adjust any settings?

 

[2Biz]

Nope! Totally happy with the way it works and how efficient it is!. Cost to operate is 1/10 of the old 350k boiler.