Winterizing heads with ethylene glycol

[thinwater]

Pre-2000 the bellow was the Jabsco recomendation. Any reason why this is not still so?

(from a 2000 forum post)
"The manufacturer is, I believe, ITT Jabsco. Another name on the first page of the manual is PAR. The direct quote comes under the Maintenance/Service Instructions and is as follows: "If charging the holding tank with anti-freeze by pumping it through the toilet, use only the ethylene glycol based anti-freeze. To use petroleum based anti-freeze may cause damage to the internal rubber toilet parts." The manual came with the Hunter Owner's manual for a 1996 29.5. The Models pertaining to the manual for the head are 29090-0000 and 29120-000."

The 2012 advise is different; draining is recomended.
CAUTION: The use of anti-freeze is NOT RECOMMENDED, as it is impossible to ensure that it penetrates the complete toilet system. If, for any reason, anti-freeze is used it MUST be glycol based.

Of course, if the glycol is pulled in through the suction side, glycol will work well. Why did the wording change? I suspect PG is not good for the pump and EG is not politically correct.

The reason for the EG preference, of course, is that the joker valves and other soft parts in Jabsco heads are neoprene, which is rated for EG but not rated for PG. Other brands (Raritan and Groco) use nitrile soft parts, and the PG compatibility is better. EG could be a hazard if someone drinks the balckwater, but there should be no difference in marine toxicity or POTW treatablity.

I've used EG on the blackwater side for years (PG for potable, of course) for this reason. No problems and good joker valve life.

 

[Peggie Hall HeadMistress]

"If charging the holding tank with anti-freeze by pumping it through the toilet, use only the ethylene glycol based anti-freeze. To use petroleum based anti-freeze may cause damage to the internal rubber toilet parts."

That was a mis-statement that should have been caught during proof reading and corrected to read, "use only potable non-toxic propylene glycol..." Ethylene glycol is a petroleum based antifreeze. It was corrected (sort of anyway) in later instruction sheets. But even then, their so-called technical writers don't seem to be aware that there are two types of propylene glycol...the automotive version (the recommended replacement for ethylene glycol in engines) is NOT the same thing as non toxic propylene glycol, aka "pink stuff." And only the "pink stuff" that should be used in any plumbing, fresh water or sanitation. Ethylene glycol should not be used in any marine application because it's a pollutant.

 

[Mulf]

Peggy!

Nice to see you still drop in. You helped thousands of us over the years. I wish you happy holidays and a healthy new year!

 

[thinwater]

"If charging the holding tank with anti-freeze by pumping it through the toilet, use only the ethylene glycol based anti-freeze. To use petroleum based anti-freeze may cause damage to the internal rubber toilet parts."

That was a mis-statement that should have been caught during proof reading and corrected to read, "use only potable non-toxic propylene glycol..." Ethylene glycol is a petroleum based antifreeze. It was corrected (sort of anyway) in later instruction sheets. But even then, their so-called technical writers don't seem to be aware that there are two types of propylene glycol...the automotive version (the recommended replacement for ethylene glycol in engines) is NOT the same thing as non toxic propylene glycol, aka "pink stuff." And only the "pink stuff" that should be used in any plumbing, fresh water or sanitation. Ethylene glycol should not be used in any marine application because it's a pollutant.

No, it was NOT an error. I have spoken with Jabsco engineering this week and that is still their unpublished position. It turns out that soft parts of the Jabsco heads are neoprene, which is rated for EG but not for PG. Goolgle "glycol + compatibility + neoprene", find a table, and you can confirm that this is true.

The notion that PG is better for plastics and rubber does not withstand close scrutiny and puzzles me. In fact, the aggressive nature of PG towards nylon, neoprene, and certain other seal materials that has kept it out of the OEM automotive market. If there is documentation, I would be interested, but the assertion certainly counter to industrial and commercial expereince.

Both EG and PG are petroleum products. There is, of course bio-source 1, 3-propanediol which is a byproduct of biodiesel, but it is not the PG we are generally familiar with. My company makes both. The reference to petroleum-based was sloppy writing an no one is certain of the meaning.
(Industrially, propylene glycol is produced from propylene oxide,[3] and global capacity in 1990 was 900,000 tonnes per year.[4] Different manufacturers use either non-catalytic high-temperature process at 200 °C (392 °F) to 220 °C (428 °F), or a catalytic method, which proceeds at 150 °C (302 °F) to 180 °C (356 °F) in the presence of ion exchange resin or a small amount of sulfuric acid or alkali.)

There is no measurable difference between EG and PG with regard to marine pollutants. This has been studied re. airport runoff. This can be googled and I have posted links before.

True, there are minor differences between automotive PG and winterizing PG; the additives in automotive PG are selected for corrosion protection and are slightly toxic. Certainly only winterizing/potable water system PG should be used in potable water systems. However, that is NOT what we are talking about; we are talking about blackwater. Assuming what is toxic to people is toxic to marine organisms and bacteria is off target. By that reasoning, people would need to remove zinc from their diet (deadly marine toxin but needed by people and often taken as a dietary supplement).

So, if manufacture statements and marine toxicity (unless there is a study I have not seen) are not reasons, is there another.

 

[Peggie Hall HeadMistress]

I guess all the other toilet mfrs are wrong, then.

 

[thinwater]

I guess all the other toilet mfrs are wrong, then.

No, they are not wrong. I did not say they were and did not mean to imply that. They have different requirements. The OP specifically asked if EG was still the better choice in a Jabsco head, nothing more.

Jabsco makes soft parts from neoprene, Groco and Raritan use nitrile. I stated this in the OP. Neoprene is better in some regards, nitrile better in others.

I asked an honest question and have provided verifiable information.

 

[RichH]

Chemical compatibility is not as simple as looking up in a chart for the listed components.

The compounding of such polymers includes fillers, stabilizers, etc. Every manufacturer has different 'recipes' for such 'auxiliary' compounds and components in these materials. Over time the components of the compounding may change simply due to changing of the component suppliers.

Chemical compatibility also depends on the concentration ('strength" or potency) of chemical and 'mixtures' used. Many times chemicals that are diluted (with water, etc.) become 'more aggressive' vs. certain polymers. Temperature of the chemical or mixture affects the efficiency chemical compatibility and/or the "rate of reaction".

For example two major manufacturers of NEOPRENE O-rings; ColeParmer lists compatibility vs. Ethylene Propylene as only FAIR (softens, swells and deforms under long term exposure) while Parker lists the compatibility is Excellent .... probably the result of different compounding and additives/fillers. They are BOTH 'correct'.

In the final analysis, technical users of these polymer seals/rubbers/O-rings usually do stability studies of the compounds versus the target chemical mixtures ... and simply select the 'manufacturer' who produces the 'best' chemical resistance based on 'practical testing' and evaluation under actual physical test or actual service conditions. Lets hope that the 'toilet makers' have a single source supplier for their 'neoprene' and make their recommendations based on long term usage of these suppliers ... and thats why 'toilet manufacturers' etc. stock these parts and components ... so you don't fall into the trap of 'unknowledgeably' reading a generalized chemical compatibility chart on the internet and simply make the wrong selection. Either trust the OEM manufacturer, or take your OWN risk.

Sinple speak: just because a chemical compatibility chart shows a certain resistance, DOES NOT mean that 100% of the time that the expected results will be 100% correct. (And thats why chemists and chemical engineers are needed, to constantly evaluate and monitor). Manufacturers usually have gone through the trouble and have 'product service history', etc. all worked out, and thats why they keep in stock these components.

This is all like getting information from "internet experts" who many have absolutely NO practical or scientific basis .... thank them; but, take the info but then VERIFY through your own usage conditions or practical analysis. Use your eyes and brain to Verify for the EXACT conditions, the exact temperatures and chemical concentrations of the mixtures for long term service after making a 'selection' ... or simply purchase the components direct from the manufacturer who hopefully has already 'worked this out'.

;-)

 

[catsailor]

Sinple speak: just because a chemical compatibility chart shows a certain resistance, DOES NOT mean that 100% of the time that the expected results will be 100% correct. (And thats why chemists and chemical engineers are needed, to constantly evaluate and monitor). Manufacturers usually have gone through the trouble and have 'product service history', etc. all worked out, and thats why they keep in stock these components.

This is all like getting information from "internet experts" who many have absolutely NO practical or scientific basis .... thank them; but, take the info but then VERIFY through your own usage conditions or practical analysis. Use your eyes and brain to Verify for the EXACT conditions, the exact temperatures and chemical concentrations of the mixtures for long term service after making a 'selection' ... or simply purchase the components direct from the manufacturer who hopefully has already 'worked this out'.

;-)

All very true. I have 30 years in the chemical and refining industry and agree with every word. If I added every explanation, disclaimer and engineer's caveat to every post they would get a trifle long winded.

However, I only used general compatibility tables to support the determination the manufacturer had already made based upon their practical experience. I used general expereince to explain why Jabsco made a recommendation that was contrary to those made by 2 other makers using different materials. I have also soaked joker valves in an appropriate concentration of EG and PG while restrained by a flange in the appropriate temperature range, and there are observable differences. How do these translate into longevity? As you've stated, such simple tests tell only a limited part of the story and so I did not mention them and won't detail them here. But I believe Jabsco engineering does have long expereince with this, in just the way you suggested. I have not contradicted any statement by any manufacturer.

So my single question remains unanswered; is there some reason--other than manufacturer recommendations as they have already made it clear in writing that it is preferred--not to use EG in a Jabsco head?

____________

The use of a phrase in quotes is generally trite. I'm not trying to prove I'm smart, I've not posted incorrect information, and I'm not running anyone down. I have not taken another's words beyond what they have written. And I AM an expert in the testing or glycol based engine coolant for cars and trucks; I have been on those ASTM committees for 20 years, produced the products including the development of some significant proprietary long-life innovations, have done the lab testing, and have done the field testing. We are an OEM supplier. Yes, this is different and I understand testing of this sort well enough to be mindful of practical limitations. But all of that is off the original question, since I am not second guessing the manufacturer, I am agreeing with them.