Century Boiler Fluid and Aqua Hot and floor heating

[Gary.Jones]

Larry

You are making this more complicated than it needs to be. Bottom line.... AquaHot professionals that I know to be expert in working on these units say to never mix Century Boiler Fluid with Camco Boiler fluid. Now, I along with you have never done the chemical experiments that would be necessary to answer the question, and I'm darn sure that people at Entegra and Spartan have not done the experiments to know one way or the other. So, missing experimental data in real life situations, I personally value the opinion and advice that comes from those working with these devices on a daily basis.

When you say that there is no problem mixing boiler fluids (they are the same ....), you are telling everyone who reads your post that they should go ahead and mix to their heart's content. All I am trying to do is present the other argument. There has been a question on whether this is a major problem or not since the introduction and use of Century Boiler fluid X number of years ago. Until there are real answers, my recommendation will be the same. Mix them at your own risk. That is all I am trying to do.... give what I understand to be good advice and make people aware. I'm not splitting hairs.... to me this issue is very clear.

One guy at one company that probably has never repaired an AquaHot in his life is not the person to be telling other people facts about what is, and is not, good practice, IMO.

Again, I could be wrong.....

Gary

[lwmcguire]

Most all the Aquahot systems I have been around that serious problems such as gunking or sludge had ssplit tube and hard water entering the antifreeze loop

However this should cause an overflow situation which apparently didn't happen

Corrosion and over heating can create serious issues as well including sludge

Propylene glycol is just that however corrosion inhibitors could be added as we know dye is

People have been known to add hard water for dilution

Only distilled or deionized should be added

Pull up the SDS sheets and compare analytes

[garysfb]

Originally Posted by 757driver

Gary,

For the most part the system should burp itself with use. With regards to your rear Aquahot heat (back loop) are there any red lights on the status panel in the basement illuminated? Perhaps the pump is not working. Is the rearmost line coming out of the Aquahot unit (going to the middle pump) hot to the touch? Perhaps the check valve is stuck closed.

Thanks Don. No red lights however their are two red lines coming out of the unit. One is very hot, one slightly warm. Don't know where the check valve is, time to pull out the manual and educate myself better.

Seems I barged into the wrong thread as there is another thread 'zone 3 not working' where you have posted a picture with explanation of the zones and pumps, well sort of. At any rate I believe all my green lights are coming on as they should, can't check pump 3 until the temp down there goes below 55. So it may very well be the check valve. Thanks again!

[jestal]

In the past I have taken great pains to get the detailed MSDS for both Century and Camco boiler fluids. The MSDS info indicates both contain propylene glycol, water and nothing else. Nothing else is listed for either so I question the idea of any corrosion inhibitors or anything else in the fluids. Simply some cheap propylene glycol premixed with water and sold at a substantial profit margin in both cases. And mixed inaccurately with who knows what kind of water......

Mixing Century and Camco should cause no problems since propylene glycol is propylene glycol no matter who mixes it with water and sells it. The idea of the dyes causing a brown rust appearance is valid.

I have found that both the Century and the Camco fluids turn brown with time indicating some corrosion is going on somewhere. Since the boiler is the only rust prone area of the system (plastic lines do not rust) I would expect it to rust particularly in the high heat areas of the fire box or burner enclosure.

I drained my system and refilled with Prestone Lo-Tox automotive coolant. This is also a propylene glycol based coolant which is non-toxic. But, it does contain trace amounts of silicates for corrosion protection. This is non-toxic also. I can also mix it exactly 50/50 since it is not premixed like the Century or Camco.

My system filled, burped and run with 50/50 Lo-Tox for the last 3 years has maintained a bright green color as original with no signs at all of discoloration or sediments forming. Twice yearly I drain a gallon out of the boiler drain and check it for 50/50 concentration and clearity. It is always perfect and I pump it back in the boiler drain to refill the system. No discoloration, no particulates and no sign of corrosion.

The corrosion inhibitors are needed in this type of system as alluded to by Camco, Century and Aquahot but no one seems to provide them.

Additionally, I have checked the concentrations of Century and Camco premix fluid many times. Using two different hydrometers I always get the same results that the Century and Camco are very inconsistent bottle to bottle and generally show as high as 20 F for freeze point indicating they are nowhere near 50/50 PG/H2O. My 50/50 mix of distilled water and Lo-Tox propylene glycol based coolant always shows -50F as the freeze point confirming the 50/50 mix.

Conclusion: if you are using Century or Camco you are getting nowhere near the 50/50 mix mentioned. This just increases the profit margin for them with less than 50% PG and that you have less freeze/boiling protection in the system plus no corrosion iinhibitors.

Since the fire box burning diesel fuel likely runs well above the boiling point of a less than 50/50 mix I suspect nucleate boiling at the surface of the burner and thus the tendency for rust and resulting discoloration of the fluid. Not "right" but that is what is happening. Doesn't happen with the 50/50 Lo-Tox.

Your results may vary and it is solely up to you to put what you want into your Aquahot but the results I have seen offer some interesting conversation points.

This might be a good argument for buying the Century concentrate and mixing it yourself to get a 50/50 mix instead of the roulette method of pouring in what comes out of the premixed jugs.

I would highly recommend everyone serious about their Aquahot longevity to get a refractometer and measure the concentration in the system to see what the freeze/boiling protection (percent propylene glycol) you actually have. I always see way less than 50/50 when I have checked camping neighbors' systems out of curiosity.

The Lo-tox vs. Century/Camco is an argument for another thread...…..

[Renegade RV]

Originally Posted by Gary.Jones

Gene

Your not posting the follow-up is the least disturbing problem i have had today....

On the phone with DirecTV trying to get a working DVR shipped to me on the road.... have not had one that works since Aug 2nd. This company is almost impossible to work with since AT&T bought them out..... Avoid this company if you can.....WHAT A ZOO........! -- -- --

Gary

I switched to dish for our coach. I’d be glad to sell you my DirectTV DVR. PM me if you interested.

[757driver]

Originally Posted by garysfb

Thanks Don. No red lights however their are two red lines coming out of the unit. One is very hot, one slightly warm. Don't know where the check valve is, time to pull out the manual and educate myself better.

Seems I barged into the wrong thread as there is another thread 'zone 3 not working' where you have posted a picture with explanation of the zones and pumps, well sort of. At any rate I believe all my green lights are coming on as they should, can't check pump 3 until the temp down there goes below 55. So it may very well be the check valve. Thanks again!

Gary,

The red line coming out the top of the Aquahot that is only warm may have either a pump that is not working or a stuck check valve. Take the front cover off of the Aquahot and tape the plastic plunger in so the unit will run. The check valve (silver) is located at the bottom of the unit before the pump. Give it a controlled wrap with a tool to unstick it. Feel the pump to see if it is running and check for a red light on the status panel while attempting to run that pump.

[BobG88]

Originally Posted by oneknight

While you're shopping on Amazon, This https://amzn.to/2mU98Mj (with the end of the spout cut off, and a short piece of plastic tubing attached) makes filling the aquahot overflow tank a breeze.

Thanks Jim - I ordered one, and it's definitely an easy/inexpensive way to avoid a mess! Thanks,

BG

[Gary.Jones]

Jestal

Interesting arguments. I will file them away with my other information on this issue. I have a refractometer and will check my concentrations. I have generally bought the pre-mix (think that is all there has been until recently with the new highly concentrated version).

Again, thanks for the insights and observations. Something more to think about...

Gary

[757driver]

I presently have Camco pink in my system which I installed 1.5 years ago when I put in new Buehler pumps. The Century fluid was completely flushed out.

Aquahot recommends a concentration of between 35-50% propylene glycol and distilled water. A 35% mixture will have a freeze point of 1F (-17C). A 50% mixture will have a freeze point point of -29F (-34C). See the table below. The choice is yours depending on your situation and how cold you think your fluid will get while in storage. Keep in mind the greater the concentration the greater the possibility a check valve may stick due to the syrupy solution. I would not go with a concentration greater than 50% or -29F (-34C). The only proper way to check the concentration is with a refractometer. For my situation I have my concentration at 40% propylene glycol which is a freeze point of -6F (-21C). As water evaporates from the system the concentration will increase slightly.

I cannot speak to what is in Century green fluid but the concentrated Camco pink HAS corrosion inhibitors and Dipotassium Hydrogen Phosphate, and inert ingredients. See the picture below.

[jestal]

Thanks for the info Don. Guess my memory of coolant tables failed "remembering" 50/50 PG/H20 was -50. You are correct it is -29 F for 50/50.

In my haste I mis-spoke. I have two refractometers which I use to check the PG concentration NOT hydrometers......duh...should proof read. Both the refractometers correlate so I'm confident of the mix ratios.

I agree that 50/50 begins to be a bit viscous and I would not go any higher on PG concentration because of that. I am not worried about freezing point as much as boiling point. The higher concentration of 50/50 provides more protection against boiling at any hot spots on the burner chamber which is why I chose to run it there. So far flow seems adequate for proper operation.

I need to get new MSDS sheets? Maybe since this conversation went into this depth several years ago Camco was reading and added the corrosion inhibitors because at the time nothing was shown for either on the sheet or the bottle. The Century bottles I have still do not show any corrosion inhibitors. In any case I have a lot of experience with the silicate package the Lo-Tox uses and it is particularily good at plating the hot surfaces and providing excellent corrosion protection against hot spots. So... since the Aquahot is on my own dime now I want to protect the heat exchanger portion as much as possible.

[Flanz]

Some light reading on Hydronic Systems using Propylene Glycol

https://heatinghelp.com/systems-help...ronic-systems/

Heatinghelp.com is a newsgroup for heating and cooling professionals as well as homeowners with questions. The newsgroup, within heatinghelp.com, is called “the wall”. This newsgroup is similar to the Entegra newsgroup but you’ll get questions answered by folks that are actually in the heating and cooling industry.

When I was a homeowner I did a complete redo of our heating system. This included a new boiler and plumbing for multiple zones. This newsgroup answered many questions that helped me design and install our new heating system....

[Magic-carpet]

Originally Posted by 757driver

I presently have Camco pink in my system which I installed 1.5 years ago when I put in new Buehler pumps. The Century fluid was completely flushed out.

Aquahot recommends a concentration of between 35-50% propylene glycol and distilled water. A 35% mixture will have a freeze point of 1F (-17C). A 50% mixture will have a freeze point point of -29F (-34C). See the table below. The choice is yours depending on your situation and how cold you think your fluid will get while in storage. Keep in mind the greater the concentration the greater the possibility a check valve may stick due to the syrupy solution. I would not go with a concentration greater than 50% or -29F (-34C). The only proper way to check the concentration is with a refractometer. For my situation I have my concentration at 40% propylene glycol which is a freeze point of -6F (-21C). As water evaporates from the system the concentration will increase slightly.

I cannot speak to what is in Century green fluid but the concentrated Camco pink HAS corrosion inhibitors and Dipotassium Hydrogen Phosphate, and inert ingredients. See the picture below.

Don, how is the original color of the fluid holding up after 1.5 years?

[757driver]

Originally Posted by Magic-carpet

Don, how is the original color of the fluid holding up after 1.5 years?

Jeanne,

The colour of the fluid is holding up great.

[Magic-carpet]

Originally Posted by 757driver

Jeanne,

The colour of the fluid is holding up great.