Community Forums

Wayne R · 09-12-2006, 01:31 AM

I just replaced the stir pump on my Hydro Hot 2 weeks after the 2 year warranty was up. There are 4 rigs in our park that have had leaks around the 2 year mark. 2 were stir pumps with the outlet port cracked where the hose attaches and 2 were the pex fitting for the drain. All these rigs were owned by full timers. I suspect using the units 24/7 for about 2 years is causing the plastic to get brittle and crack from heat, the stir pump is not cheap $179. By the way one of the units was an Aqua Hot.

I talked to tech support but they were not aware of any issues, I find that hard to believe since there are 4 rigs in our small park with the problem. I suspect casual user will go years with out having a problem. I plan on changing the drain valve and associated plumbing with brass probably less than $10 worth of parts at Lowes. Not and economical mod until there is a need to drain the unit or a leak develops. The anti freeze is $19 a gallon and hard to find. Tech told me to mix it 2/1 the service manual says 3/1?? The unit takes around 4 ½ gallons.

Wayne R · 09-12-2006, 01:31 AM

I just replaced the stir pump on my Hydro Hot 2 weeks after the 2 year warranty was up. There are 4 rigs in our park that have had leaks around the 2 year mark. 2 were stir pumps with the outlet port cracked where the hose attaches and 2 were the pex fitting for the drain. All these rigs were owned by full timers. I suspect using the units 24/7 for about 2 years is causing the plastic to get brittle and crack from heat, the stir pump is not cheap $179. By the way one of the units was an Aqua Hot.

I talked to tech support but they were not aware of any issues, I find that hard to believe since there are 4 rigs in our small park with the problem. I suspect casual user will go years with out having a problem. I plan on changing the drain valve and associated plumbing with brass probably less than $10 worth of parts at Lowes. Not and economical mod until there is a need to drain the unit or a leak develops. The anti freeze is $19 a gallon and hard to find. Tech told me to mix it 2/1 the service manual says 3/1?? The unit takes around 4 ½ gallons.

Lyle & Cath · 09-12-2006, 06:28 AM

Wayne, that is certainly a cheery note. Speaking of the anti freeze where did you find it? Looks like I need to add a little. I am not having very much luck locally.

Lyle & Cath
Apex 1
DataStorm #3491

Wayne R · 09-12-2006, 08:22 AM

Lyle, I ordered it from Vehicle Systems, its not here yet. I ordered 4 gallons 1 for my buddy and 3 for myself since it will take 2 to refill my system when I determine it is leak free. The pump and drain assembly are just another thing to be aware of as you approach the end of the second year. The Stir Pump is easy to change, about the same as changing one of the old style heater valves on our cars. The other weak spot I am aware of is the drain valve assembly which will be a piece of cake.

BruceJaxn · 09-13-2006, 09:46 AM

Wayne,

Remembering that the HydroHot manual specified that the anti freeze solution required was propylene glycol, I discovered that the solution used for winterizing RV water systems is proplyene glycol. This is an inexpensive pink solution, sold in gallon jugs most everywhere, such as Camping World and Wal-Mart. I have been presuming this solution is suitable as a HydroHot anti freeze. Do I have it wrong? Thanks. Bruce

Wayne R · 09-13-2006, 05:12 PM

Bruce,

Quote from the Aqua Hot Installation Manual, this should also apply to the Hydro hot

"NOTE: Because of the significant impact various types of antifreeze can have on a
Hydronic Heating System - including the level of safety provided, Vehicle Systems, Inc. has recognized a need to provide an explanation regarding two additional prominent types of antifreeze/coolant available. The following information should be utilized as an educational means of ensuring that the proper type of propylene glycol based antifreeze is selected:

RV & Marine Antifreeze: These types of propylene glycol based antifreeze products are formulated specifically for "winterizing" applications only. Although RV & Marine antifreeze is often "Generally Recognized as Safe" by the FDA, it should never be used in the Aqua-Hot's Hydronic Heating System. This type of antifreeze is not formulated to transfer heat, which is essential to the Heating System's functionality and does not contain rust inhibitors.

Automotive Antifreeze/Coolant: These type of propylene glycol based antifreeze products are formulated specifically to protect automotive engines against corrosion, freezing temperatures, and overheating. They also have excellent heat transfer and thermal conductivity characteristics. Although these types of antifreeze products are considered less toxic and safer than ethylene glycol for people, pets, and the
environment, they are not "GRAS" (Generally Recognized as Safe) rated by the FDA. Therefore, they must be marked with a "harmful if swallowed warning. This additional warning is required because these types of antifreeze products contain high levels of chemical rust inhibitors. Due to their potentially hazardous properties, they should never be used in the Aqua-Hot's Hydronic Heating System. "

Snuggery · 10-25-2006, 05:23 AM

I have been researching this and have identified 3 brands of PG-based antifreeze that have rust-inhibitors, good heat-transfer characteristics, and are GRAS (in case a leak gets some into your drinking water) and are thus suitable for AquaHot and HydroHot systems.

Dow Dowfrost
Union Carbide (now owned by Dow) UCar Foodfreeze
Camco Boiler Antifreeze - 100

Where can you buy this stuff? It appears to cost about 10x what regular antifreeze costs or around $20 a gallon plus shipping. Also, I can't find a supplier unless I want 55 gallon drum quantities.

Wayne R · 10-25-2006, 05:50 AM

I ordered mine from Vehicle Systems, they will sell and ship 1 gallon.

anthem4us · 11-10-2006, 05:16 PM

Wayne

Did you have to keep putting antifreeze in the overflow tank? I can't see any leaks around the Hydro Hot so I don't know where the fluid is going. Which pump is the stir pump and how hard was it to change? I have changed the nozzle and fuel filter and it was not that difficult. Also changed one of the temperture sensors.

Thanks Larry

Wayne R · 11-10-2006, 07:57 PM

You won't have any trouble changing it sense you have done the nozzle. The stir pump is to the right of the burner unit. Easy to change expensive part $170. Most of the leaks I am aware of (6) have been where the drain valve connects to the storage tank. The easy fix for the drain is to replace the fittings and valve with brass and iron parts from Lowes or Home Depot. I spent about $10 to change mine while I was in there. Cheaper than a gallon of anti freeze latter. My stir pump cracked where the rubber heater hose connects to the plastic inlet up next to the pump. I suspect this is accelerated by being hot 24/7 it also could have been stressed when installed. Remove the burner and the job is a lot easier.

Yes I was adding anti freeze to the overflow tank. At first there was no sign of the leak. It probably was evaporating before I would check it. Eventually it got bad enough that I could see it drip.

Also if you haven't done it, down load the Service, Parts and Installation manuals from their web site.

PS: in a pinch, waiting on parts the stir pump could be disconnected and by passed. With little ill affect except maybe not as much continuous hot water when the heat was on.

Ted III · 11-12-2006, 01:15 PM

Out of curiousity does it bother you that all of the problems you seem to be having with your Hydro Hot are in relatively new motor homes. We had it in our 96 Monaco and never encountered any problems at all in the 4 years we had it and we bought it used.

Wayne R · 11-12-2006, 01:52 PM

Ted III,

Yes it bothers me, and it is across all MH manufactures and also applies to the Aqua Hot. Using plastic fittings in a boiler environment exposed to hot temperature 24/7 is not good. The circulation pumps are also made of plastic.

PS: Did you use your Hydro Hot and or Aqua hot 24/7 for the 4 years. I suspect the plastic will hold up when not heated 24/7.

Ted III · 11-12-2006, 02:03 PM

Wayne, no, in all sincerity I did not use the unit anywhere to that extent, but I do know the previous owners did and I had a pretty substantial record of their maintenance and the Hydro Hot was not one of them.

Cruzer · 11-12-2006, 03:29 PM

I checked with Vehicle Systems regarding this when I got my HydroHot. They told me NOT to use regular antifreeze nor the winterizing stuff. Just having Propylene Glycol versus Ethylene Glycol is not enough. The PG stuff is merely non-toxic, while the EG stuff is. What you really need is 100 degree boiler antifreeze to prevent damage to the HydroHot boiler. They recommended Camco boiler antifreeze. Here's A Link to the Camco site. The good part is that any RV dealer has access to Camco products through their distribution channels because they make sewer house, etc. My dealer quoted me about $8.00 a gallon and he could have it within a week.