Hydro hot coolant

[Jerry Emert]

Is the green coolant in the hydro hot the same as antifreeze you put in a car?  If not what is it called and anyone know where it is usually sold. Need some today if possible. Also what's the secret to getting the radiator cap off?  I've been trying but am afraid to break it. Thanks. And thanks to Orman for earlier help.
Jerry

[Tic Wilson]

Jerry, do you have green coolant in your hydro-hot now?  The green coolant is dangerous poison.  It is not used in the event of a leak between the fresh water and coolant exchanger.  You should be using a red coolant containing (Propylene Glycol) such as that from Camco, Walmart or most places that sell RV supplies.  Do not mix the two.  You may need to have that system drained and flushed.

On my system, fluid is added to the overflow bottle when the fluid is cold.

Boiler Antifreeze Concentrate is a specially formulated antifreeze for use in RV Aqua-Hot and Hydro-Hot heating systems.
The product contains Propylene Glycol and an inhibitor system for use in this type of small boiler system. All ingredients are on the FDA list for approved food additives and the product is generally regarded as safe (GRAS) per FDA guidelines. The concentration of Boiler Antifreeze Concentrate requires the product to be mixed with two parts purified or distilled water to one part product for normal usage.

The product utilizes a special inhibitor system to prevent any bacterial or algae growth in the heating unit and prevents system corrosion for extended periods of time. Also, Boiler Antifreeze Concentrate protects from freeze damage and prevents system corrosion when used as directed.
 

[Jerry Emert]

Thanks. The pipes have a green tint but the overflow tank is empty and I can't get the radiator cap off. Tried but afraid to break it. Is the green the same as used in a car?  I would like it to work tonight and tomorrow the. I can get it in to be looked at.

[Tic Wilson]

Definitely not the same!

[Steve Huber Co-Admin]

Jerry,
Green antifreeze is same as in your car. Probably a 50/50 mix. Hydro Hot folks told me a few years ago that any brand (i.e. Prestone) is OK except NAPA. (not sure why). Tic is right that you can have real problems if this fluid contaminates your water. This is a concern with Aquahot system. Thus the boiler fluid is spec'ed. On a Hydrohot, the antifreeze and water systems are totally separate so chances of contamination are very remote. But if you run the red, you're adding insurance.

The cap can be tough to get off. Mine had the large cap and I had to have someone push down on it while I used a long screwdriver to get enough leverage to get it to turn. If it's not leaking, I'd leave it be. Removing it may damage the cap/gasket. Add antifreeze to the expansion tank and it will eventually fill the system.
Steve

[Joel Ashley]

I see Steve posted here before I completed my spiel, and made similar comments, but I'll throw mine in the ring anyway:

Some True Value stores and other hardware outlets and Camping World or some RV dealers carry the fluid Tic is talking about, Camco Boiler -100 fluid.  It is the generally prescribed stuff, and if you have translucent hoses to your heat exchangers, you should see pink fluid inside them where they are visible in bays and behind cabinet drawers, etc.  But I understand some have used regular automotive antifreeze in their units, that it is not an uncommon practice, and it apparently isn't harmful to the system.  As Tic mentions, however, using the two types of antifreezes together is probably not a good idea.

It sounds like someone used automotive antifreeze in yours, your hoses likely display a green hue, and so I'd stick with that;  but others here can probably offer more clarification, such as Gerald, Ed, or Orman, especially as to draining and switching over to boiler antifreeze if you opt to do so.

Do not confuse RV water systems winterizing antifreeze with the Camco Boiler antifreeze.  They are both pink.  Make sure the container says Boiler antifreeze that protects to -100 degrees.  Winterizing antifreeze (-50) is not for contained boiler systems like hydronics.

-Joel

[Jerry Emert]

Thank you all!  That's what I need to get it going and not be afraid it will burn something up. Thanks again!!!

[Edward Buker]

Steve,

My understanding of the Aquahot unit, if you have one, is that it is safe to run 50/50 Automotive Prestone given the tankless coil is wound on the outside of the tank and never has any contact with the boiler solution. Mine is a 100 series unit and I cannot speak to all models but I believe that is correct for mine.

My message is to research the unit you have and see what the owners and service manual says before draining and replacing fluids.

Later Ed

[Steve Huber Co-Admin]

Ed,
You are correct. See Orman's response from a few years ago; http://beaveramb.org/forum/index.php/topic,539.msg2948.html#msg2948

Not sure why  Hydro Hot factory told me when I asked specifically about use of ethylene glycol that it was OK to use??? My HH had it in when I bought the 01 Contessa (2nd owner) and from condition at the time, I doubt it had ever been serviced.
Steve

[Bill Sprague]

The coolant required depends entirely on the model you have.  There is a chart that tells what was recommended.  Fear over being poisoned has confused many AquaHot and HYdroHot owners.  My suspicion is that some coaches have a mixture of the two types and it is unclear what that does or does not do.

Here is the chart:  http://rvhydronicheaterrepair.com/RVHYDModelInfo.htm   Look in the right hand column.

[Steve Huber Co-Admin]

Bill,
Thanks! That clears up a lot of confusion (at least on my part). I took the liberty of condensing Roger's material to focus on coolant type. May make looking it up a bit easier.
Steve

[Stan Simpson]

I can't get the radiator cap off. Tried but afraid to break it.

I see that no one has answered this. I hope you got the cap off. Generally, you have to push down, hard, and then twist. On mine, and others that I've seen, the hose clamp coming in to the neck (that the cover is on) blocks you from pushing it down hard enough. I loosened the hose clamp, then slid it out of the way, temporarily, and was able to push the cap down enough so that it would twist off. Reverse for putting it back on.

Stan

[Jerry Emert]

update and many Thanks for all your responses.  It was pretty cold this weekend, for me anyway, in the 30s.  The first night we were pretty cold so I was determined to get the HH going.  I could not get the cover off so I put prestone 50/50 in the surge tank.  I was 90% sure because of the color that it was what was in it.  I filled the surge tank to between the cold and hot marks.  I turned it on and everything seemed to work with the exception of two registers, fans I think.  After it heated up I checked it and the level was higher than when I had filled it.  This indicates to me that it is working and has enough coolant.  It ran a lot the last 2 nights which gave me dreams of diesel dollar signs flying out the windows but we were warm!  The cap will have to wait for awhile.  Its due for service so I'll get it checked at that time.  Thanks again for your help.
Jerry

[LaMonte Monnell]

On mine I have had to use a screwdriver between the sides of the cap handle and turn the cap that way to remove it..Tighten it back the same way.

[Steve Huber Co-Admin]

From my earlier post;
The cap can be tough to get off. Mine had the large cap and I had to have someone push down on it while I used a long screwdriver to get enough leverage to get it to turn. If it's not leaking, I'd leave it be. Removing it may damage the cap/gasket.
Steve