Mod Cons and Glycol

Drew_2

If I rememeber the noise created when glycol is used in some systems is cured by changing the flow. Don't mistake 50% Noburst AL with 50% propylene glycol content.
50% Noburst AL will give you 35% propylene glycol content. A 35% propylene glycol concentration will change your heat transfer by about 3 to 4% Vs water and will protect to zero freeze/-10 flow/-60 burst.

Yes, make sure you use the correct antifreeze for aluminum.

Ragu_5

Opinions?

Going to look at a house next week that is a potential candidate for a mod/con. Renovated old farmhouse, lots of radiators, ancient oil boiler and an illegal chimney.

Unfortunately, there are some severly cold areas in the crawlspaces and if that never gets rectified, then the replacement unit is a strong candidate for glycol; actually, it will be necessary.

Would you guys even consider glycol in a mod/con? Thanks.

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Brad White

Yes, Jack

The only limitations are pressure drop depending on the HEX type and to have the mixture not too rich (30% I think, maybe more).

There is a tendency for micro-boiling at the thin surface where the fluid meets the heat exchanger wall. Isolated pockets of water within that boil rapidly and cause a moaning sound throughout the piping. Heard about that here first. Who knew?

I would guess Drew at Noble (The No-Burst folks) may be able to guide you to more specifics. Others such as ME have heard it themselves and have a much better handle on the concentration in practice.

That post about the HEX freeze through the OA inlet is sobering. It occurred to me but not enough to ask...

Stay warm,

Brad

Guy Woollard

Glycol

Brad is correct in the percentage of glycol for a Mod/Con. Many mfgs will allow up to a 50% mix, however 30% is nearly always sufficient for protection without really having any profound effect on BTU output and flow head pressure.

Be aware that the aluminum HX have specific needs regarding glycol.

Guy Woollard
N.E. Regional Sales Mgr
Triangle Tube Corp.

hr

I would highly recommend

either the Nobel No-Burst or Rhomar Rho-Guard.

Rohmar has spent a lot of money and time to develop a top quality multi metal PG. It is available full strength, 50-50 blend or custom blended. All with DI water. Also sold in 5 gallon containers.

Multi metal glyol is best since your mod con will be either stainless or aluminumu.

If not glycol consider Rhomar 922 conditioner. In either case use their multi metal boiler cleaner first.

Here is a system I flushed, cleaned and treated with 922 and Rho-Guard yesterday. It's a snowmenl and recieving bay system at Watts.

hot rod

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chris_86

Other posters!!!!!!!

Feel free to post the brands of "heaters" that allow any substance other than water in their mod/cons!

Your looking at a heat exchanger or do the right thing in the first place and add insulation where it belongs!

hr

wrong side of the bed today, Chris

seems like a lot of angry posts.

Actually some of the mod con manufacures are not listing names of products, both glycols and treatments that are acceptable in their equipment.

It took some time for the manufactures to test and approve various products. Not something to rush into. Some have discovered products that are actually harmful to certain HX materials.

I believe Weil, Slant fin, Buderus, are some that have this info in the latest installation packets. I'm sure more will follow when the see the results of proper cleaning and treatment.

Or lack of!

hot rod

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chris_86

No, I got out of bed period,...

Another construction related death in New England...

Ragu_5

I asked, and I have received....

Thanks, you guys. This is where I come when I want to get beyond sales hype/ brand hype etc. I have some mental digesting to do.

I would be specifying a Vitodens with a stainless steel heat exchanger; aluminum is not for me at this time.

Brad: What can I say? You are a truthful man.

Hot Rod: You have done more than most of us.

Drew: You are not scared (as a Manufacturer) to step up.

I thank you all. Jack


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Unknown

From The Knight I&O Manual -
Freeze protection fluids –
"• NEVER use automotive antifreeze. Use only inhibited
propylene glycol solutions, which are specifically
formulated for hydronic systems. Ethylene glycol is
toxic and can attack gaskets and seals used in hydronic
systems."
I believe that I read in W/M's manual that you have to use special antifreeze for aluminum but they certainly allow antifreeze.
"Munchkins'" I&O also allows antifreeze.
I'm not aware of any mfr of a modcon that specifically states that you shouldn't use antifreeze.
I'd suggest that you choose the boiler you want to use and check with the manufacturer.
The only concerns I would have is to be aware of the pumping characteristics and allow for the decrease in heat transfer.

bob_50

Not sure

if this is relevant. On the Amana HTM's we had a lot of trouble with anti freeze breakdown, it would turn acid. I think this was caused by small heat transfer surface area and high local temps in heat-x. I think I would keep a close eye on ph.

PointBlueBullet

Super freeze conditions...

I'm building a seasonally use house near Lake Superior in Wisconsin - thus house will be subjected to weeks where the high temp will be below zero - with no heat. Considering spec'n Vitodens 200 due to SS HX - is there any issue with glycol in these units?

Pump sizing calcs land exactly on GPM / Head curves for Grunfos UPS15-58 pumps -

Are there any "learnings" as one approaches the boundaries of sane construction techniques with respect to boilers, glycol, pumps?

Thanks

chris_86

It's worse than that,...

If you carefully paruse the manuals many refer to piping "in parallel." That's manufacturer speak for heat exchanger. Most warn about the redux in efficency. And all never name a particular brand, wheather it by cryoteck, insluguard, polyprotect, or whatever. But you can be assured that whatever you pick if anything goes wrong the manufacturer will want a site visit before any warranty compensation. The only other certianty is if you add chemicals, now you will need a "testable" backflow device and according to the latest codes that's a rpz, not the chhepest plumbing apurtanance on the block. In Boston they don't care if you hang the little hercules tag that says non-toxic YOU NEED A RPZ period. And even if the heater manufacturers booklet says it's ok your tubing manufacturer has a say as well, onix has a few quirks about what type of freezz protection runs thru that glorified radiator tube. Actually except for the price and it's heavy in the larger sizes it's great stuff, just don't put any alcohol based liquids as one example.

chris_86

You might consider a wood, or pellet fireplace, and solar based design for the home. It dosen't make sense to do what your doing.

PointBlueBullet

Glycol system..

We considered alternate heat sources, but need to transfer heat throughout structure better than blowing air around. The building design doesn't bode well for airflow, so we had to put radiant on-floor system. I would consider using a wood/pellet furnace as a supplemental energy source. With radiant, glycol is the only option as water would freeze by Oct.

It sounds from reading the posts on this thread, that glycol does break down in mod con boilers? Are certain brands better than others?

hr

glycol doesn't go bad without a cause

usually from prolonged overheating. Glycol is used sucessfully nin many heating and solar systems. You jneed to use it as directed and test it ocassionally.

Mod cons have overtemperature protection, you should be fine with a properly glycoled mod con, stainless or aluminum.

hot rod

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ALH_4

glycol & failures

I do not think I have ever seen a glycol-caused failure, and regular maintenance to the glycol is almost never actually performed. How many people have their heating company come out and test their glycol each year? How many people test it themselves? Though, I have never worked with aluminum boilers, and if I did I would insist on annual maintenance. A thorough flushing of the system is a good idea to clean away any extra flux inside the pipes, which is quite acidic.

There is no problem at all with 50% solution of propylene glycol. It does increase the head loss and decrease the heat capacity of the fluid, but this is not a problem as long as the flow rates are adjusted accordingly and the circulators are sized correctly. This booklet by Grundfos is a handy reference for the hydraulic calculations.

Bernie Riddle_2

In the ball park

There were post before that stated the avg newly construtced home home is in the 25-35btu X per sg ft, range
you seem to fall there [very eff built is under 25]

My "New" home came in at 32K-39K btuh... currently running an Ultra80> In the low 20°'s, I run constant circ at 1300 RPM or 16K btu input>> DD of 0° had me around 28-32K btuh
Also Running AL-glycol, so no huge loss there

ALH_4

-

Mitch_4

Dunkirk

The manual specifically mentions that Intercool NFP 50 is approved. That is for a cast aluminum boiler BTW