Radiant Heating Problems

Ray M_2

Fred, this boiler should have been set up with primary -secondary piping.NTI's web site has a phone nunber for tech help. LOL




Ray m

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[Deleted User]

Radiant Heating Problems

I am trying to heat a 3000sq. ft. home with radiant heat and I can not get floor temps above 76 degrees. When the contractor installed the tubing it was according to specs. the problem I had with him was the size of the header. The boiler is an NTI, 45000btu to 145000 btu rating, which is more than enough, the piping comming out of the boiler is 34inch and he increased it right away to 1 inch for about 2ft. then increased it to 1 14inch this the main header. Now he put in tees and reduced to 34 and through an mixxing valve then through a pump (taco 007) after the pump he supplies 4 seperate zones with taco zone control, the total feet of pipe is about 1900ft. if all zones call at the same time. (using 12inch pex) That is just the upstairs the same process is used to feed the downstairs but the total length of pipe is about 2000ft. of pipe. He wants me to add heat plates but don't know if I should, the floor is insulated with 12 inch foam board with aluminum backing, I told this should be enough. I am waiting for the manafactur of the pex to send any information on gpm for the pex tubing. Can anyone give any advice. Thanks Fred..

heatboy

Questions.

What is the heat loss for the entire house?

What is the heat loss for each floor?

1.25" will easily carry 16 GPM, which at a 20° Delta T is 160 MBH. So that's not the problem. At 3k sqare feet, your heat loss won't be anymore than 80K BTUH, if you have any insulation at all.

76° floor temp. What is the temperature in the stucture.

What water temperature is in the mixed loops?

How many loops make up that 2000' of tube? Should be at least 7.

There are more questions to come.

hb

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Brian

Radiant

Fred
I agree with Ray the Trinity's should be piped primary/secondary,but I think your problem is with your clip-up.I don't think 1/2" insulation is enough.I think also we need the answers to hb's questions before you will get an informed opinion.

Good Luck
Brian

Frank_3

Doesn't make sense

I just don't see why people are using those units (or similar systems from other manufacturers) for heating. They just don't make sense.

First, regardless of how big you make the supply and return manifolds, the boiler still has only a 3/4" pipe running through it and you're not going to get 16gpm through that size pipe without other problems, if at all.

Second, the marketing folks had a field day with this thing by putting such a high btu/H rating on it. Yeah, it'll put out 130k btu/H but -- read the literature -- at a delta T of 85 degrees, and only 3.1 gpm!!!!

So, what's the actual capacity of the boiler at a more typical 10 to 20 degree delta T that you'd find in a heating system? Hmmmm... the literature doesn't spell that out but doing the math it'd probably be only around 40,000 btu/H, as you'd expect for a 3/4" pipe.

The system is undersized, regardless of whether it's piped primary-seconday or not.

Frank_3

Doesn't make sense

I just don't see why people are using those units (or similar systems from other manufacturers) for heating. They just don't make sense.

First, regardless of how big you make the supply and return manifolds, the boiler still has only a 3/4" pipe running through it and you're not going to get 16gpm through that size pipe without other problems, if at all.

Second, the marketing folks had a field day with this thing by putting such a high btu/H rating on it. Yeah, it'll put out 130k btu/H but -- read the literature -- at a delta T of 85 degrees, and only 3.1 gpm!!!!

So, what's the actual capacity of the boiler at a more typical 10 to 20 degree delta T that you'd find in a heating system? Hmmmm... the literature doesn't spell that out but doing the math it'd probably be only around 40,000 btu/H, as you'd expect for a 3/4" pipe.

The system is undersized, regardless of whether it's piped primary-secondary or not.

heatboy

You mean..........

it's not a boiler? I had no idea since I have never heard of a Trinity. What exactly is it? All of those good questions, too................

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Ray M_2

Trinity

Frank, THat 85 degree delta t is the rating for domestic h2o.The boiler needs min 6gpm passing through it.This is why it needs primary secondary piping.
Raym

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[Deleted User]

Trinity info...

You're not alone HB, I've never heard of one either. Must be one of them East coast phenomenons. Did a Google search and found this http://www.radiantdirect.com/page2.html

Based on what the HO is saying (oo7 pump) and what the web site is saying about the boiler having a stainless steel heat exchanger, my guess is that the pump can't generate enough oompf to move the fluid at a decent velocity to get the fluid through the circuit before it gives up all the btu's to the wrong side of the floor. That compounded by the choked near berler piping, and you got yourself one thermally constipated system. Then, confuse them slowly wandering btu's with some semi reflective wannabe 1/2" insulation and you got yourself a radiant disaster looking for someones house to happen in. Looks like it found a home eh...

Got pictures???

Here's what the web site has to say about it.


THE TRINITY

All-new, ultra-compact, high-efficiency boiler and water heater

We feel this the best boiler available in the world!!

Ten Year warranty Five year full, next five pro-rated.


1. Available in both Natural Gas and Propane versions with a modulation system that eliminates additional models.
2. State-of-the-art sealed modulation combustion system with hot surface ignition.
3. Innovative condensing heat exchanger provides ultimate efficiencies.
4. All connections are conveniently located for ease of installation.
5. Wall mount configuration saves valuable floor space.
6. Vents easily with conventional ABS or CPVC plastic piping.
7. Condenser does not use aluminum but is constructed totally from stainless steel, which is a proven material for condensing appliances.
8. The distinctive casing design reduces costly standby losses, while virtually eliminating combustion noises.
9. High-capacity heat exchanger provides ample domestic hot water.
10. The Trinity is certified, designed and rated to CSA and AGA codes

This is not a instantaneous water heater

All instantaneous water heaters are below 80% efficient and drop much lower when used for heating.

This is a stainless steel, wall hung boiler that is 94%+ efficient.

It has a modulating burner that can heat from 80,000 to 200,000 Btu's

It is a very very quite, full condensing, sealed combustion, direct vent, boiler with a built in indirect water heater.





The all-new NTI combustion system
NTI's new state-of-the-art combustion system allows the TRINITY to modulate the burner to the exact size required to meet the conditions of the system. The TRINITY incorporates an electronic state-of-the-art combustion system to reduce the amount of gas that is injected into the burner, to ensure proper combustion throughout the full range of modulation. This system also compensates for extended venting; therefore, adjustments are not required between short and long vent runs. The TRINITY is a totally sealed combustion system: all combustion air is drawn from outside, used for combustion and then expelled. This eliminates any need for fresh air intake into the room, thereby decreasing heating costs. Exclusive NTI heat exchanger
NTI has developed a sophisticated heat exchanger that provides virtually endless hot water, at unheard-of efficiencies. The condenser does not use aluminum but is constructed totally from stainless steel, which is a proven material for condensing appliances.





ME

[Deleted User]

More 411 from the Horses Mouth...

http://www.nythermal.com/Media/Docs/Pdfs/NTI_Trinity_Brochure.pdf

The boiler has a 6 foot pressure drop.

Let's see, 6 foot for the boiler, plus 4 feet of head for 250 circuits, plus distribution piping of approximately 4 feet equals 14 feet of head.

And a 007 can move 4 to 5 GPM at that head...

5 GPM at a 20 degree delta T = 50,000 BTUH.

50,000 BTUH divided by 3,000 square feet = 16.6666666 btu's per square foot per hour... I don't know, if it's a real well insulated home, it should work...

Ya don't think that maybe the fact that it's suspended tube has anything to do with it do ya?

Let's look at it backwards. He says he gets no more than 76 degree F floor temps. For each one degree difference in floor versus room temperature, radiant floors deliver 2 btu/square foot per hour.

So, 76 minus 70 equals 6.

6 times 2 = 12.

So the floor is actually delivering 12 btus per square foot per hour. It could be delivering a whopping 16 btus per square foot per hour. Whats the back loss for 1/2 thick insulation with reflective surface?

Use plates with REAL insulation and see what happens.

By the way, did any body perform a heat loss calculation prior to specifying/designing this system?

Just curious.

ME

[Deleted User]

Radiant Heat Problem!!!!

2000' at about 250' there is 8 loops, 1900' at about 250' there is 6 loops. Boiler output temp is at 170 and the mixxing valve is at 160 degrees, I have to run this temp just to get 76 on the floor. The basement is at about 55 degrees, it was well over 70 before I insulated the floor. The return temp is 140, but it takes awhile to get that temp. I tried this, to pump 1 zone with 2 loops at 250' a loop, close one loop and it takes about 6 mins. to cir. hot water 250'. To get 70 degrees in the space it takes well over 5 hours, the zone will shut off and not call again for 3.5 to 4 hours. I am trying to get information from the contractor on the heat loss on house. Again I thank you all for your help.. Fred

Brian