Another Hydro Hot question

[Bill Jourdain]

I had to make a trip to Tampa a few weeks ago and decided to have the Hydro Hot serviced at Lazy Days while we were there.  They are an authorized Hydro Hot service center.  We were very busy while we were in Tampa and I did not have an opportunity to look in the Hydro Hot bay before we left.  I opened the bay yesterday and noticed that the plastic bottle mounted above the Hydro Hot system in the bay (overflow bottle?) had the cap unscrewed and sitting off to the side.  That bottle has lines for "hot" and "cold" fluid levels, but I did not see any fluid in the bottle at the cold level.  Is this the fill container for the ethelyne glycol solution?  If so, I'm concerned that perhaps the service tech perhaps forgot to place fluid in the container, or maybe he just forgot to replace the lid.

Should fluid always show at the "cold" line on the container?  How do I go about confirming that the level in the system is correct?

Thanks.

Bill

[Steve Huber Co-Admin]

Bill,
The plastic container is the expansion tank for the antifreeze solution. If Lazy Days drained and replaced the solution, they would have probably removed the large "radiator cap" on the top of the unit for re-fill. I think this would have been shown on the bill as a complete refill takes a significant amount of anti-freeze. In this case, it follows that the tech failed to refill the expansion tank to the Cold level. You can open the Radiator Cap to see if they refilled the unit (Make sure unit is cold) or add solution to the expansion tank as it drain into the unit. Since you said it's been a few weeks since the work was done and assuming you've used the heaters in the coach, my guess is that they failed to refill/recap the expansion tank as a system shouldn't have heat if there was no/little anti-freeze. Solution in the expansion tank should be at the Cold level. I found that after draining, I had to add solution to the expansion tank a number of times until the unit was finally "full".
Steve

[Bill Jourdain]

I ran the system before I discovered the cap off and it produced plenty of heat.  Is that indicative of a sufficient amount of solution in the system?

[Steve Huber Co-Admin]

Yes, but I would add solution to get expansion tank level correct.
Steve

[Bill Jourdain]

Thanks, Steve.  Is this the same solution we use for winterizing - the pink antifreeze?

[Steve Huber Co-Admin]

Bill
NO! Aqua Hot uses a boiler antifreeze. If you don't have any, I would first call Lazy Days where you had it serviced and ask them what they used to refill the system and obtain same. Aqua Hot's web page shows service centers nation wide if you need to obtain some.

After talking to Aqua Hot, I switched mine to a 50/50 Prestone/distilled water mix a few years ago and have had no problems but sticky valves might be in my future (see the other Hydro Hot thread). In any case it certainly makes topping off a lot simpler. Only caveat from Aqua Hot was NOT to use NAPA brand antifreeze. Don't know why but suspect it may have to do with lubricant properties addressed in mentioned thread.

Strongly recommend you stay with antifreeze that Lazy Days used and do not mix types.

Steve

[Bill Jourdain]

Thanks.  I will check with them and find out.

[Joel Ashley]

http://www.amazon.com/Camco-35116-Boiler-Antifreeze-Concentrate/dp/B004804N7E/ref=sr_1_1?ie=UTF8&qid=1351841705&sr=8-1&keywords=Camco+boiler

I've found it at some True Value stores and Camping World in one gallon jugs around $15-18.  Amazon has gallon jugs, but in a 6-pack, which would be for a full system replacement I reckon.  The 32 oz concentrate diluted with equal part water would be adequate for topping off our surge tanks occasionally, and easily carried in a bay.

Amazon also has this,  http://www.amazon.com/gp/product/B006JRKQ48/ref=pd_lpo_k2_dp_sr_3?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B004804N7E&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1FC8MQPE7XYJ6KTNPY3Q

Joel

[Bill Sprague]

NO! Aqua Hot uses a boiler antifreeze.

Not necessarily.  It depends on the model and year.  Somewhere around 2005 they changed to using "Boiler Antifreeze" which is the same chemical as the pink stuff, but at a higher concentration.

Ours is an "old style" HydroHot in our 2004.  It uses standard automotive antifreeze like Prestone.  

There is a low fluid cutoff switch below the "radiator cap".  If there is fluid above that switch, the system will run.  The expansion tank makes operation less messy and servicing easier.    The fluid will rise when hot and fall when cold if the radiator cap does not leak and the unit itself is full.

[Steve Huber Co-Admin]

Bill,
You may be right. My statement was based on what I was told by the Aqua Hot rep when I drained my system in 2006 so he may have been referring to the newer units. In any case, I've always avoided mixing anti-freezes.
Steve

[Bill Jourdain]

Given that my coach is a 2002, I assume it uses the older stuff, but I will check to be sure.  It's possible LD put the newer pink fluid in as well.  Thanks for all of the input.

Bill

[George H. Wall]

If it's GREEN colored, it's REGULAR AUTO antifreeze!!!    Henry

[Bill Sprague]

Go to this website:  http://www.rvhydronicheaterrepair.com/RVHYDModelInfo.htm.  Scroll down to see all the models.  To the right of the model number the antifreeze type is listed.  Many use the green ethylene glycol automotive antifreeze.  The switch to propylene glycol based "boiler antifreeze" has to do with failure types.  My understanding is that in the models where antifreeze could leak into the water, the more expensive and harder to find boiler antifreeze is recommended or required by AquaHot.  On the units that would could leak and not enter the water system the cheaper automotive type is used.

In some cases, the same model will use a different type, depending on date of manufacture and serial number.

[Steve Huber Co-Admin]

Bill,
Good info.
THX! Steve

[Bill Sprague]

Bill,
THX! Steve

You are very welcome!