Aqua Hot Coolant?

[Summersgal]

I have been searching today here on the forum and have been trying to find out what everyone is using for coolant when you change the system out? Jeff has changed out the filters and etc that needs to be done but we aren't sure which coolant everyone has been using and would appreciate any input on this.

Thanks
Pam:thumbsup:

[RussWhite]

Hi Jeff and Pam,

While I can't speak for everyone I will be glad to give you my thoughts and will assume you have the same vintage AquaHot as I do :
Model 431XE/12
S/N 98487XE

First I am not sure what you are contemplating as there is no recommendation to replace the coolant based on age or hours. It does not come into contact with any engine or burner contaminates and should last a very long time. There have been reports of the ph getting out of range. It should be above 7.5 and not alkaline according to Roger Berke - kind of a AquaHot guru. If you are considering a wholesale change, just beware there is a lot of it in the system and it is very difficult to get all the air out later. If you are just wanting to top off the overflow bottle, that is much easier. The coolant used is a 50/50 mix of ethylene glycol and water ( distilled would be best ). Hope that helps.

Russ

[Richard and Rhonda]

Ethylene Glycol does not go bad and lose it's freeze resistance. As Russ said the ph can get out of whack and turn it into a base or acid. Neither is good for your system. The most common problem is that the coolant loses its rust inhibitors over time. They are consumed.

You can add a quart of coolant rust preventative to the system rather than change it out.

[Summersgal]

The main reason I had for changing out the coolant is I have no history of previous owners actually maintaining a 50/50 mix. Did they add just water when coolant bottle was low, or did they add just straight coolant? Was the same type/brand used each time? My coolant level is fine, just unsure if correct ratio/type has been maintained.

Jeff

[RussWhite]

Jeff,

Okay - makes sense. If you plan on going ahead I think the quantity is around 16 gallons. I have the bleeding procedure and if you PM me your email I will get it to you. Good luck. Russ

[busnut]

You can use a hygometer to test the strength of the mixture. A 50/50 will give you about -40F or -40C.

You can get PH strips also to test acidity level.

[Lewis and Clark]

Hello Russ,
I have a 1996 #410 and I just removed my Aqua Hot inorder to change my fresh water tank (leak). Would you please send me the bleeding procedure @ meo721@hotmail.com

Thanks,
Nando Garbarino

[prairieschooner]

Makes sense to use a Hydrometer to check the Coolant then check the PH. This ould be a simpler and less expensive approach. Not sure if this will help you know if the PO used Distilled Water though. I use Distilled water as a regular course of action, this would help keep down corrosion issues. Now the Chemist, Richard may have another idea but we all have elbows!

[Chester B. Stone, Jr.]

I am curious regarding the above recommendation to use ethylene glycol vs Aqua-Hot web page which specifies propylene glycol which is GRAS approved.

[RussWhite]

Chester,

I think you will find the original poster has an AquaHot model 431 vintage. Those were designed for ethylene glycol.

Here is a quotation from Roger Berke's great AquaHot forum:

"Your Aqua-Hot model 431 uses standard ethylene glycol coolant (Prestone or equal).

Any automotive supply or big box store sells ethylene glycol coolant that "is compatible with all coolants". You do not need to use the propylene glycol (Camco) coolant in your Aqua-Hot"

At some point the design changed and those new units are clearly tagged as requiring propylene glycol.

Roger runs two forums. One is free and the other is premium. You get two years on the premium forum just for purcahsing any part from him. If you just want to join the premium I thinks it's only five dollars. Here is a link to the free one:

http://forum.rvhydronicheaterrepair.com/forum.php

Hope this helps. Russ

[rheavn]

I believe Newell made the change around '04 or '05.

[tuga]

Checking and adding coolant rust inhibitors is very important. A couple of years ago Richard and I (mostly Richard) tore into my Aqua Hot. I had a leak in the tank; after removing it we found that the tank was corroded and needed to be replaced.

I contacted Aqua Hot and they informed me that they would only sell a new tank to an authorized Aqua Hot dealer. So I contacted Newell and had them do the job. $5,000 to replace the tank, parts and labor. The tank was $2,700. My coach was about 10 years old at the time.