Can I run Hydrohot after winterizing?

[Keith Duner]

Hopefully this is an easy question.  Can I run the furnace side of the Hydrohot system after I have winterized (I've already put pink stuff in all the freshwater hot/cold loops).  I'd like to keep warm while putzing in the coach.  I did a quick search on winterizing Hydrohot and didn't see this... sorry if it has already been answered. Thanks

[Bill Sprague]

Yes, you can.  And, it is good for it.  It circulates a little fuel through the important parts.

Another thing I like to do is run the generator with electric heaters plugged in.  The idea is to run it at a half load or more for 30 minutes a month.  Besides the wall outlets, good places to plug in are the washer/dryer and microwave.  The idea is to get 15  to 20 amps on each of the two legs.  I use my Aladdin to get it right.  Another good source for a generator load is the block heater.

On a really cold day, I can go from a very cold motorhome to cozy real fast with both the HydroHot and Onan making heat!

[Keith Duner]

Thanks for the quick response Bill, much appreciated.

[David T. Richelderfer]

Okay... so we have two loops in the coach - a fresh water loop and an engine coolant loop.  The only place where these two loops "talk" to each other is at the heat exchanger located within the Hydrohot.

The engine coolant loop runs through 1> the engine (obviously!), 2> the coach's furnace heating system (its fans are controled by the thermostats in the several zones), and 3> the heat exchanger located in the Hydrohot?

The Hydrohot has three ways to provide heat to its heat exchanger - 1> from the engine, 2> from the Aquahot (electric element), an 3> from the Diesel Burner... with all three of these heat sources warming the engine coolant loop... which in turn provides heated coolant through the heat exchanger to the fresh water loop.  Interestingly, the Hydrohot not only can get heat from an operating engine through the engine coolant loop, but also can provide heated coolant to warm a cold engine before starting on a cold Winter day.

Regardless of whether the fresh water loop was winterized by pink stuff or just blowing out using air pressure (no pink stuff), the Hyrdohot can be used with no limitations to the Aquahot, the Diesel Burner, or the engine.

Do I accrately understand the "programming" of the fresh water loop, the engine coolant loop, etc.?

[David T. Richelderfer]

I found this.  Go read it either in part or in whole.  It reads like there are three loops 1> the fresh water loop, 2> the engine coolant loop, and 3> a separate "Hydrohot loop" that also contains engine coolant.

http://www.rvtechlibrary.com/heatair/hydronic_tips.htm

[Bill Sprague]

........Regardless of whether the fresh water loop was winterized by pink stuff or just blowing out using air pressure (no pink stuff), the Hyrdohot can be used with no limitations to the Aquahot, the Diesel Burner, or the engine.

Blowing the water out is great for traditional propane water heaters.  It is not a good idea for the HydroHot/AquaHot.  Water can settle in the bottom of the coils and you will have to replace the entire unit if it freezes.

[Bill Sprague]

...Do I accurately understand the "programming" of the fresh water loop, the engine coolant loop, etc.?

I think so, except for two parts.

First, as I tried to make clear, don't winterize by blowing out the water.  There is too great a risk you won't get it all.

Second, each loop requires a pump.  All  rigs have a pump to send water to the house heat exchangers.  Some have a pump to send diesel heated coolant to the engine, but not all.

So, everyone has three sources of heat:  a little electric, a lot of diesel and some from the engine.  

Everyone can use that heat for the house and water.  Some can use it for preheating the engine.

Of the various circuits or paths of liquid, the only one that can can freeze is the domestic water.  So, if you can't keep it warm, you fill it with pink stuff.  The other loops have antifreeze in them of one type or the other.

[Joel Ashley]

Do I accrately understand the "programming" of the fresh water loop, the engine coolant loop, etc.?

I suspect you are a bit confused yet, judging by the way you used the terminology.

Vehicle Systems built hydronic systems they called AquaHot and also a smaller version, HydroHot, commonly used in shorter coaches.  As the link you provided re. Tiffin Allegro coaches explains, Vehicle Systems changed their name to reflect their main product, AquaHot.  HydroHot is not a component of a hydronic unit, but rather it is an entire hydronic unit, just a smaller capacity AquaHot.  These days, since the company name change, the smaller units are called AquaHots too, and only older models retain the name HydroHot.

All models, regardless of size, have what's called MotorAide and route engine coolant through themselves to take advantage of the "free" heat, but not all models have pumps to push prewarmed coolant back to a cold engine, which is more easily started at 80-100 degrees than at 40.  Hitting the engine preheat switch on a 3-switch panel, about a half hour before you plan to start the engine, depending on outdoor temps, is a good idea;  and if you have an Aladdin you can monitor the engine warmup.  

I prefer not to use the term "furnace" if it's avoidable.  It's one unit, called a Hydronic unit (not a furnace and not a water heater as exclusive entities), that heats by electric or diesel or exchanged engine heat, both water for human use and fluid sent to remote exchangers for heating space, including critical "basement" bays.  Water heating has priority and the space heating will stop during times the hot taps are turned on, in order to achieve that goal.  The diesel burner heats things up vastly faster than the electric element.  And keep in mind that AquaHot, Inc. is not the only manufacturer of hydronic units;  many coaches have systems you will read about in this Forum called Hurricanes.

Joel

[Robert Mathis]

There are actually three "loops" to the system. The main loop circulates heated boiler fluid from the boiler thru the various heat exchangers to heat the coach. Each has a separate thermostat and fan. The second loop circulates cold fresh water thru coils in the burner to supply domestic hot water, and the third loop circulates engine coolant thru the boiler to either heat the boiler fluid while the engine is running, or to preheat the engine, if your unit has that feature. I learned more about this system than I ever wanted to know when our engine was replaced. The shop neglected to secure the line to the bedroom heat exchanger (furnace) and they came into contact with the turbo, which melted the lines and we lost our boiler fluid. We didn't discover the problem until we set up on the Keenai Peninsula. We had to drive back to Anchorage, go to Karen's RV, where the mechanic and I spent the better part of the day correcting the problem.

[David T. Richelderfer]

I am beginning to understand why this Hydrohot system costs $12k to $13k to replace.  I am told IF IF IF you can find a refurbished unit it will cost about $8k and, I suppose, that does not include installation.  Refurbished units are very difficult to find, I am told.

I had my system blown out, did some investigation, and took it back to have pink stuff pumped in.  That $12k to $13k replacement cost is nothing compared to a properly done winterization job... with pink stuff...  even though it can be a pain to get all the pink stuff out next Spring.

[Bill Sprague]

...  even though it can be a pain to get all the pink stuff out next Spring.

True only if it was done by pouring pink stuff into the water storage tank as the method of getting it into the system.  If done properly by going directly to and through the pump,  it flushes out in minutes by opening all the taps.  If you forget the outside shower or washer/washer dryer it can seem that you are not getting it all out.   If you are unsure, drink and cook with bottled water for a day or two next spring when you thaw out.

[David T. Richelderfer]

The pain of getting the pink stuff out includes the washer/dryer, as you said, but the real pain seems to be getting it through the ice maker and perhaps washed through the filters in the kitchen sink faucet and the Insta-Hot.  All the free flow lines, both hot and cold, to the toilet, sinks, shower, etc. is no problem.  Just turn them on and let them flow for 5 or 10 minutes.

When we bought the Marquis this past August, the dealer apologized up front about not being able to get all the pink stuff out of the ice maker.  We let it make enough ice to fill the ice bucket two or three times... and that seemed to do the job.  The dealer had most of the pink stuff out, but not all as evidenced by slightly off color ice cubes.   lol

For this winterization I did not pump pink stuff through the ice maker.  Since I had blown out the whole system before hand, I simply turned off the valve to the ice maker, and left the two water connections open behind the fridge.  The washer/dryer was overlooked for getting pink stuff.  It was blown out for sure. BUT I am told I need to pour 1/2 gallon of pink stuff in it and run the pump.  Pumps in the washer/dryers seem to be notoriously overlooked and often freeze-break over winters.

[Sean Donohue]

This is why I use Whiskey to winterize... Better Ice Cubes...