Tankless Water Heater

Anyone install the Precision Temp RV500 in a park model RV??? 

No, but I'm interested to know more if you go that route.  I think it's a fabulous idea to use those in a house or an RV, and Europe is already making tankless water heaters the standard.  Might be something to look into for my 89 Winnebago.  Do you know how it would compare to a regular tank heater?  (Is there a limit on how long the water runs hot?)  I'm new to all this.

Margot

Karmabytz said:

Do you know how it would compare to a regular tank heater?  (Is there a limit on how long the water runs hot?)  I'm new to all this.
Margot

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I have a tankless water heater in my South San Francisco home, but cannot have one at my Reno home because there it gets too cold for a tankless. You do NOT want to use them if there is a chance for the water in the tankless "tank" to turn to ice. They really do have a tank to hold about one gallon or so. You don't want that to turn to ice. It can ruin the tankless water heater. There is no warm water when it is NOT being used. However, some (such as mine) have an electric heater that comes on when it gets below 40F or so. But it is NOT enough to help if it gets well below freezing as it does often in Reno's Winter.

A tankless water heater NEVER runs out of hot water. You can keep the hot water on all day and it will stay at about  the same temperature, regardless of how many faucets are on. There is a computer in the better ones to set the temperature. Smaller cheaper ones will have limits. Some work much better than others. There's been a lot of problems with older smaller units. Perhaps these days, they all work a lot better. I am very happy with mine which is about two years old. It is a Takagi T-K3 See here:http://www.google.com/products/catalog?q=tankless+water+heater&oe=utf-8&rls=org.mozilla:en-USfficial&client=firefox-a&um=1&ie=UTF-8&cid=367915684068575199&ei=rm_yS-DmOYPMsgOzxuiUDA&sa=X&oi=product_catalog_result&ct=result&resnum=5&ved=0CEEQ8wIwBA#

One disadvantage is that when you first  turn on the hot water it takes a lot longer for the water  to get hot when compared to a tanked type, unless it was just used in the last few minutes. This is because it's all starting with cold water, not only in the tankless "tank", but also has to warm up the  hot water pipes. Also, there is about a six second delay for the water heater to even start when the hot water is first turned on. In my house, I have to have the hot water on for at least a full minute before I start to get some  warm water. This will be less of a problem in a RV because you probably won't have as much pipe to warm up. But when you once have the hot water, you can keep it on for a week and you will not run out of hot water.

This link was in today's RV newsletter....

http://rvnow.rvtravel.com/2010/05/optional-replacement-for-rv-water.html

That tankless water heater shown in the link is a 120 AC type heater, 12.5 amps/1500 watts to run that baby!

You'll be committed to AC power to get your hot water - no propane options using just that unit alone!

Don't know if I'd like to have to fire up the genny every time I need some hot water... :-[

There are tankless, propane water heaters designed just for RVs, but they are pricey, over $2,000 for smaller units, I believe...

Ray

The RV500 is LPG fired by 12VDC igniter, and DOES have a defrost feature in that as long it has LPG & 12VDC it will turn on if water gets too cold to prevent freezing. their customer service is awesome as well and they provide service manuals free for your downloading pleasure and they are very simple to work on!

love mine!

The RV500 looks like a neat product. Cost is around $1000 plus installation, though.

http://www.houseneeds.com/shop/HeatingProducts/WaterHeating/rv/rv500waterheatermainpage.htm

I am assuming there are no concerns about the draw. Will these units exceed the available amperage on some sites?

No concern with the RV500 - it is propane fired.  But if using an electric demand heater, power draw is a major concern, with the trailer's own electrical system capacity as well as the campsite.  Many Rvs are limited to 30A @120v, for a total of 3600 watts for all purposes. Larger RVs often have 50A @220v, so less of a constraint.

The site power will match the RV power system, though a 30A site may also have a 50A outlet.

Tankless water heaters designed for homes usually cannot be installed in RVs without voiding the warranty. The smaller electric units (like the one linked above) would be suitable only for supplying one fixture at a time. As Gary pointed out, the electric units are power hogs.

As far as I know, there are only two tankless water heaters designed and recommended to replace the tank type water heaters in RVs: the Girard and the RV-500. Both are propane fired only and use 12v only for the ignition and control circuits. The Girard is a less expensive, bare bones unit that will fit in the hole previously occupied by a six or ten gallon water heater (because of the lower cost, it is the one most commonly being installed in high end RVs by  RV manufacturers). The RV-500 will only fit where a ten gallon water heater originally was unless there is room to do some surgery on the sidewall of the RV. Both will put out enough hot water for a shower (I saw a demonstration of the Girard earlier this year and it does put out plenty of hot water).

The advantages of the Girard are it is less expensive, has fewer parts to break, and will fit where the RV-500 will not without surgery. The downside is it doesn't have a variable gas valve so water temperature regulation is done by regulating the flow of water instead of by mixing the hot water with cold water (the more water flow, the lower the water temperature). Because of this, most consumer reviews I've read did not favor the Girard. It is an option when space and cost are a concern.

The RV-500 costs between 50-100% more than the Girard but will put out a bit more hot water than the Girard. It also has a variable gas valve and more sophisticated electronic controls so the water temperature is pretty much constant. Temperature control at the point of use is by the conventional mixing of hot and cold water. It can be ordered with optional high wind and freezing weather protection.

The main advantage of a tankless water heater is a supply of hot water that is limited only by the amount of fuel and water available. Lesser advantages include less weight when full of water and no bypass plumbing needed for winterizing which simplifies winterizing. It also doesn't have to be drained for maintenance, cleaning, or winterizing (the antifreeze one runs through the hot water lines will protect it from freezing). The main downside is they run on propane only. No more essentially free hot water when staying at a CG that charges a flat rate per night for electricity plus one would have the hassle of having to replace the propane burned. The lesser downside is the higher initial cost.

Boondockers would probably not like a tankless unit (especially the Girard since it is likely to use more water). People who stay where there are full hookups are more likely to like them. Personally, I feel the advantage of essentially endless hot water far outweighs the disadvantages but it is an individual decision.

Not sepcific to tankless water heaters in RV's, but germaine.  There is no possibility that a tankless water heater, properly installed inside a home, would freeze if the pipes inside your home do not freeze.  These systems were designed specifically for cold climates to reduce the fuel used to keep 40-gallons of water at a useable temperature and are extremely popular as retrofits in the coldest of our northern regions.

I think a propane-fired tankless in an RV is a great idea; didn't want anyone to be needlessly afraid that they could freeze-up.

I'm a little late to the party, but want to thank everyone in this thread for great information.  A couple of years have gone by now.  Anyone have some longer term experience with one of these water heaters?

Bob.n.Carolyn said:

I'm a little late to the party, but want to thank everyone in this thread for great information.  A couple of years have gone by now.  Anyone have some longer term experience with one of these water heaters?

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Around ten years, but in a home, not in a RV.    But I have NO complaints with my Takagi T-K2 here in SSF.

I have had the Garrard Gen2 for a year and a gen 1 for a year before. The ten 2 is much improved and I would recommend it. I had issues with the gen 1 and Forest River replaced it with no charge to me. I have a 2011 Forest River Berkshire RB 390.As for freezing they both have a auto circulate when the temp gets below 40.

I have used the propane model tankless for about 2 months now. So far the reviews are positive. It fires up fast, provides lots of hot water, and the pressure at the faucet seems to be much improved. The previous rigs have had the 10 gal propane/electric models. While they worked OK, the pressure would often leave a lot to be desired. The tankless has been a real pleasure.

Dumb question here, but I am less than a day into owning my first rig, so do not quite have a handle on the systems yet.

Does my current hot water heater run off propane or electricity like the fridge? (2004 Montana).

Has anyone run across an rv tankless system that can run off both?
could I install one of each (electric and propane) with some sort of bypass switch?

My guess is your Montana is like my 02 Montana.  The water heater is gas and electric and both can be used at the same time.  There is a circuit breaker for the electric side of the WH and a rocker switch on the heater itself.  Both must be turned on for the electric to work.  Just make sure you have water in the tank or the element will burn out in minutes.  Your refer automatically will switch to electric when you are plugged in and have it set to auto, otherwise it stays on gas.  Your  recovery time is faster if both gas and electric are used at the same time on the water heater.  Boondocking is gas only on both.

kjansen said:

My guess is your Montana is like my 02 Montana.  The water heater is gas and electric and both can be used at the same time.  There is a circuit breaker for the electric side of the WH and a rocker switch on the heater itself.  Both must be turned on for the electric to work.  Just make sure you have water in the tank or the element will burn out in minutes.  Your refer automatically will switch to electric when you are plugged in and have it set to auto, otherwise it stays on gas.  Your  recovery time is faster if both gas and electric are used at the same time on the water heater.  Boondocking is gas only on both.

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that is what I thought. I love the idea of a tankless heater, but would hate to lose the multi fuel option. I wonder if there are logistical issues with doing a dual option in a tankless, or if there just has not been enough demand?

We've had our motorhome for 12 years now and the only time we run out of hot water is when I forget to turn the water heater on.  It is a standard 6 gallon propane unit.  We don't take Navy showers.  We just don't dilly-dally in the shower and I don't turn the water on full-blast.