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soapy

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I would never go open loop again. It almost cost me a whole system once. You can get a small reserve tank with a pressure pump that will keep the system filled with the proper ratio.
 

mjwalsh

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I would never go open loop again. It almost cost me a whole system once. You can get a small reserve tank with a pressure pump that will keep the system filled with the proper ratio.
I have posted previous posts about the use of Spirec Heat Exchangers https://www.spirec.com/ with our facility's modular boiler system. To Soapy's point: Depending on the facility & configuration ... the deicer system can be isolated & a closed loop regardless of the combustion part of a system.

I agree with Soapy that it is not worth risking a deicer system ... having its glycol diluted with autofill water ... creating a potential freeze hazard.
 

Sequoia

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I am in Northern CA. Very cold temperatures might be 10F but that is unusual. More like in the teens as winter time lows.

Cost? I don't know. The propane tank is filled on an irregular schedule, so it's hard to pin that down. The one thing I can tell you is it is very pleasing to visit on a cold night, look at the front panel on the boiler, and see it is operating at only 20% capacity.

btw, I also bought the internet connectivity for the boiler. From my home, I was able to monitor its activity, and tweak a number of parameters for it to be more efficient in my location. While it was running. That was very handy. I watched it very closely after first installation.

I'm glad I didn't try to tackle this one myself. I'm almost exclusively DIY, but this was out of my league. My plumber did a great job.
 

2Biz

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I run Noburst Glycol mixed at 35% glycol 65% distilled water...This gives burst protection down to -50° and freeze (Slush) protection down to about 0°. With Noburst at 35% there is very little pressure loss. My thoughts are I would always let it run below freezing, so no worries on the freezing part. If there was ever a major power outage below freezing, I have a little 17amp 120v Generac Pure Sine Wave Genny that runs about 15 hours on a gallon of gas. More than enough to run the complete system @ 6-7amps....

My system is closed...I would not have an open system that could dilute a glycol mixture with tap water...Also tap water isn't the best thing for a hydronic system. Its best to use distilled water, no minerals....
 

2Biz

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My ER is in the middle of the bays. I was honestly hoping I could copy your setup biz. If I remember correctly the Takagi has to have a minimum of 40psi to operate. How do
you get 40psi when the pumps are only putting out 14-15 each?
My understanding is that the primary loop is operating at a higher PSI than the secondary loop?
Can someone explain to me the differences between a boiler and a tankless heater? They seem to be very similar but boilers are 3-4x the price? Are boilers plumbed with the same primary secondary loop system or are they plumbed directly into manifold?

Sequoia, what part of the country are you in? Do you have any idea what the utility cost is to operate your boiler? $100 a month? Less than that?

Definitely learning a lot. Thanks to all you guys for sharing your knowledge.

You don't have to have 40psi to get a demand heater to work. I think they will work with only a few PSI, but you won't get any volume through it. Every demand heater has a flow chart just like pumps have. The higher the pressure, the more flow you get. The heat exchangers in these heaters have very tiny passages to get the heat transfer. I tried multiple pump configurations starting with a "Takagi Technician Suggested" Taco 009...It only yielded a little over 2 gpm through the heater. Doing the math and more research, I settled on the two 0013's in series and get 40psi with an inline gauge attached. You are right, If a single 0013 puts out 15 psi max, how do I get 40 psi with (2) pumps? Good Question! Is the gage bad? Maybe! But I do know (2) 0013's in series gets me 6.7 gpm through the heater, and that is enough for my system to work properly...If it wasn't for the $125 surcharge on the NG, my monthly bills during normal winter months would be less than $100...That is heating floors, hot water for the bays (Soap and Wax), and heating the ER....

Yes the Primary loop operates at 40psi but misleading...It takes 6.7gpm of glycol from the secondary loop and pressurizes it ahead of the heater to 40psi needed to shove that volume through the heat exchanger then dumps the same amount of glycol, 6.7gpm, back into the secondary loop. So if my secondary loop flows at 15gpm, and the Primary loop is feeding the secondary loop at 6.7gpm, then roughly 8gpm flows through the secondary loop between the closely spaced tee's. Heater set to 105°, mixes with 60-70° return glycol and sends 80-90° glycol back out to the bays... Thats how mine works with loop length and all variables. Yours might vary slightly....But should be very similar. I would recommend you get a digital aquastat to put on the return...I put in a manual one capable of 30° differential. A digital one would be a lot easier to set up...Basically the only thing I would change with my setup...
 

MEP001

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You don't have to have 40psi to get a demand heater to work. I think they will work with only a few PSI, but you won't get any volume through it.
FWIW there are some that require a minimum pressure to heat water without damaging the heat exchanger. I looked into it some time ago when I considered using an on-demand heater with a circulating pump to heat water in an open tank.
 

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Got some bad news last night. Pressure tested my lines. A couple of them would not hold pressure at all. I could never even get enough pressure in them to move the gauge. Another I got up to 15lb but it was back to 0 with 10-15 seconds. I’m assuming this means that’s the leaks are very bad? What are the chances there are more than 1 leak in each line?
 

Noob

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They blow water out the other end when I attempted to pressurize them but would not hold any pressure.
 

Sequoia

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Got some bad news last night. Pressure tested my lines. A couple of them would not hold pressure at all.
That must be very frustrating after all the work and research you have done. Maybe someone here knows of a way to deal with this??
 

soapy

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It does not seem that it gets too cold where you are. I would look into some overhead radiant heaters that would heat the floors from above for the few times you need them per year. Add some exit side doors to keep the wind off the floor. Otherwise you are looking at new concrete and new lines.
 

mjwalsh

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FWIW there are some that require a minimum pressure to heat water without damaging the heat exchanger. I looked into it some time ago when I considered using an on-demand heater with a circulating pump to heat water in an open tank.
Based on actual experience with combustion related devices' heat exchangers' ... I would focus more on minimum maintained GPM flow. Not sure if 2Biz is using them with his on demand instant units but we would not even think of running that part of the "at risk" system without reliable flow switches. Low GPM flow during combustion may not take the heat exchanger out immediately but it will most likely shorten its life!
 

mjwalsh

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That must be very frustrating after all the work and research you have done. Maybe someone here knows of a way to deal with this??
Noob,

For my "more than normal" extensive air lines within our bays ... we use an ultra sound detection air leak phone app with a type of automotive sound amplifier ... neither was too costly. I am thinking that with a little diligence you may find that it is just one repairable leak ... even if you have to break out a small area of concrete!

Other forum members have used infrared detectors like the residual fire inspection people use. With an empty blown out system like yours I am thinking the sound graph - sound probe with one of many phone apps would be your best bet.
 

2Biz

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Based on actual experience with combustion related devices' heat exchangers' ... I would focus more on minimum maintained GPM flow. Not sure if 2Biz is using them with his on demand instant units but we would not even think of running that part of the "at risk" system without reliable flow switches. Low GPM flow during combustion may not take the heat exchanger out immediately but it will most likely shorten its life!

No external flow switches in my system. One is built in to the heater....The Takagi has to have flow before the burner will ignite. Boilers don't have this luxury!
 
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