Replace Aquahot heater

Have you made changes to your coach? Improvements? Remodel? New technology? Tell the story and show some pictures here.
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Leigh.Calnek
Posts: 6
Joined: Wed Nov 04, 2020 12:48 am

Replace Aquahot heater

Post by Leigh.Calnek »

Our 1997 Safari Continental came with an AquaHot heater that appeared to not have been serviced for many years. The electrical heater worked but the oil burner was in big trouble. Closest place for service was over a days drive and the estimated cost for repair was going to be in excess of $4K. Further, the heat exchangers did not generate much of an air flow. A previous owner had installed a propane line with a quick-connect into the cabin behind the driver's seat. I assume they used one of the various ventless gas heaters available.

After considerable discussion with a couple of my vary capable friends and relatives, I decided to discard the AquaHot unit and replace it with:
  • a standard RV water heater with electric, gas and engine heat transfer for the coach heating
  • a demand water heater for domestic hot water
  • a vented blue flame heater/fireplace located behind the passenger seat. This was done at the expense of the existing small cabinet
We have spent the last four months in British Columbia, Canada. Temperatures have ranged mostly between 4 and 8 degrees Celsius with several nights dipping to -5C.

I added a HotShot to the coach heater and use it basically to heat the bedroom/bathroom and basement. The front is heated with either the fireplace (blueflame heater) or 2 or 3 ceramic heaters running on 750 watts each.

Since it rains here a lot (understatement), we have purchased a residential size dehumidifier. This has proven very effective in terms of condensation inside the coach. Our windows are clear and moisture free all the time.

All in all, I am pleased with these modifications. I have moved from a heating system that would not have served me in this cold, wet environment. I have new equipment that I can maintain myself (have not needed any yet except replacement of a fuse and maintaining resevoir of heater antifreeze.)

Cost of the two heaters located in the back was ~750CDN each. The vented blueflame heater was $1100CDN. Additional propane lines and connections was ~$500CDN. Taxes added an additional 11%. The work was done by myself and my two very capable friends. One of these friends has gas papers and supervised the work done.

Not sure if anyone else would want to undertake such an upgrade, but it certainly has worked well for me.

-------------------
Leigh & Georgette Calnek
'97 Safari Continental/Sofa Slide
3126B Cat, MD3060 Allison
Toad: 2006 Chev Colorado 4X4

stuplich@ymail.com
Posts: 1007
Joined: Mon Oct 28, 2019 8:51 am

Re: Replace Aquahot heater

Post by stuplich@ymail.com »

Leigh.Calnek wrote:
Tue Feb 16, 2021 11:44 pm
Our 1997 Safari Continental came with an AquaHot heater that appeared to not have been serviced for many years. The electrical heater worked but the oil burner was in big trouble. Closest place for service was over a days drive and the estimated cost for repair was going to be in excess of $4K. Further, the heat exchangers did not generate much of an air flow. A previous owner had installed a propane line with a quick-connect into the cabin behind the driver's seat. I assume they used one of the various ventless gas heaters available.

After considerable discussion with a couple of my vary capable friends and relatives, I decided to discard the AquaHot unit and replace it with:
  • a standard RV water heater with electric, gas and engine heat transfer for the coach heating
  • a demand water heater for domestic hot water
  • a vented blue flame heater/fireplace located behind the passenger seat. This was done at the expense of the existing small cabinet
We have spent the last four months in British Columbia, Canada. Temperatures have ranged mostly between 4 and 8 degrees Celsius with several nights dipping to -5C.
I added a HotShot to the coach heater and use it basically to heat the bedroom/bathroom and basement. The front is heated with either the fireplace (blueflame heater) or 2 or 3 ceramic heaters running on 750 watts each.
Since it rains here a lot (understatement), we have purchased a residential size dehumidifier. This has proven very effective in terms of condensation inside the coach. Our windows are clear and moisture free all the time.
All in all, I am pleased with these modifications. I have moved from a heating system that would not have served me in this cold, wet environment. I have new equipment that I can maintain myself (have not needed any yet except replacement of a fuse and maintaining resevoir of heater antifreeze.
Cost of the two heaters located in the back was ~750CDN each. The vented blueflame heater was $1100CDN. Additional propane lines and connections was ~$500CDN. Taxes added an additional 11%. The work was done by myself and my two very capable friends. One of these friends has gas papers and supervised the work done.
Not sure if anyone else would want to undertake such an upgrade, but it certainly has worked well for me.
-------------------
Leigh & Georgette Calnek
'97 Safari Continental/Sofa Slide
Leigh.Calnek
What was cost of, and the propane BTU rating of, the water water you are using for coach heat?
Mel
'96 Sahara 3530, mine since '01
250 hp 3126 Cat, MD3060 Allison

Leigh.Calnek
Posts: 6
Joined: Wed Nov 04, 2020 12:48 am

Re: Replace Aquahot heater

Post by Leigh.Calnek »

To clarify, the heating components I used in this conversion were:
1. Martin Direct Vent Propane Wall Heater; sourced amazon.ca; current price $1265.99CAD; rating 20,000 Btu; used in main coach

2. Atwood Mobile Products 96163 Direct Spark Ignition Water Heater (energy input source electric 120V, propane, engine); sourced amazon.ca; current price $739.95; rating 8,800 Btu from 1400 watt (estimate 12,000 Btu with added HotShot); used to heat bathroom, bedroom and basement. This operates as a closed system containing standard boiler antifreeze.

3. Girard 2GWHAM On-Demand Tankless Water Heater; sourced amazon.ca, current price $783.04CAD; rating 42,000Btu; used for domestic hotwater.

Leigh & Georgette Calnek
'97 Safari Continental/Sofa Slide
3126B Cat, MD3060 Allison
Toad: 2006 Chev Colorado 4X4

TDJohn
Posts: 199
Joined: Sun Oct 27, 2019 11:34 pm

Re: Replace Aquahot heater

Post by TDJohn »

Thank you for the informative post. If you can, please post some pictures, that would be even a bigger help.

Did you try calling Hurricane factory to see what the issue was and how much the repair would have been, they are located in western Canada.
Do you still have the system, or did you end up discarding it?

The sight info for the Martin heater you installed says that minimal wall thickness for the direct vent is 4.5 inches. The coach walls are usually around 2 to 2.5 inches, how did you get around that minimal spec requirement, and was it a fuss to install the direct vent?
Did the Martin Heater give you specs on BTU input and output? (I'm trying to figure out the rough efficiency of this heater and they don't list those specs)

Did you reuse the heat registers in the bathroom, bedroom and basement from the original Hurricane heating registers?
What did you use for a circulator pump?

How much propane a month do you use during the coldest months, when not using electric heaters?
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.

Leigh.Calnek
Posts: 6
Joined: Wed Nov 04, 2020 12:48 am

Re: Replace Aquahot heater

Post by Leigh.Calnek »

I talked to a repair shop outside Edmonton. At the time I felt the costs of repair would be about the same or more than the change I decided to make. Undersand that the existing AquaHot system was not working well. The electric heater part sort of worked, but output from the vents was very poor. The oil burner was totally non-functional and was going to require major rebuild. Repairing the unit would still have left me with a heating unit that had been marginal if I interpreted the quick-connect propane line into the coach. I just decided I would prefer to try something different and more current. Having to take the unit on a 3 day round trip to get the old heater serviced was another factor. I felt that with the equipment I was planning to use, I would be able to do any service required myself.

In the end, I had the service man in Alberta remove the old heater. I return for removing it, he could keep it.

To get around the problem of the required 2.5 inch wall for the Martin heater, we built a frame 3 inches deep and fastened a piece of 3/4 inch plywood to that. The heater was then mounted to the plywood. I had removed a small cabinet to make space for the heater. Built into the cabinet were two duplex plugs. I fastened those in the space below the heater. We did have to drill a hole for the vent. The area was below the window, and fortunately we encountered no upright supports that would have been a major problem.

I don't recall seeing any information pertaining to the BTU input and output so I can't really make any comment. I do know that when I crank up the thermostat, it gives good heat. My only experience this winter has been when we would return later in the evening and the temp in the coach was down to 15C, it didn't take long to bring the comfort level up.

The back end uses the the existing registers in the bedroom, bathroom and basement. The basement register is off the hot lines to the main coach, and I have throttled that back to less than a quarter flow. I have temp sensors located at the front of the basement sitting at mid high (sits on a cargo tub). A second sensor is located behind the water control panel, behind the register. A third sensor is located in the compartment where the heaters are. It sits on the floor in amongst the hoses. In general, the temps in the basement have consistently been 10 to 12 degrees Celsius above the indicated outside sensor. For example, tonight it is windy and raining with an outside temperature of 9C. The basement temps are 15, 17, 19 C front to back.

I used the existing circulation pump in the beginning. However, it quit a year ago and pricing a replacement as per AquaHot, it was going to cost $500CAD. I was unhappy with the input/output configuration with the stock pump, so I purchased an electric pump used for automotive cooling. It has performed well this winter. I believe my cost was ~$250USD

I can't really comment on what my propane would cost as I have not used the Martin heater very much. We did use it more on the few nights where the temp went to -5, but it was always used in conjunction with the electric heaters. WE are on a 50 amp service and we have found we can run our ceramic heaters on 750w to keep us warm. Turns out it is better to have more running at 750w than fewer running at 1500W. At least that has been my experience this winter.

I will take a picture of my heating compartment when the rain quits and send it off for you.

Hope this is helpful.

TDJohn
Posts: 199
Joined: Sun Oct 27, 2019 11:34 pm

Re: Replace Aquahot heater

Post by TDJohn »

Leigh,

Thanks for the detailed description, it is a big help. I'm looking forward to the photos. If you can, please also include the photo of your Martin Heater and the box frame that you built for the direct vent.

The key reason why your old system was marginal on electric mode, is because you only have a 1500W electric element in the aqua hot, which was designed to provide hot water without needing to burn diesel. It could also be used on mildly cool days to take the chill out of the air. Being that it is only 1500W, that is only 5,118 BTUs, which is the equivalent of one, household type, electric box heater, which is not even close to enough heat output to heat the whole coach on a frigid day. If the Aqua Hot worked correctly, it would have put out approximately 40 to 50K BTUs.

Do you find that the 8K BTU propane heater puts out enough heat on the really cold days?
When time comes to replace my HWH, I'm considering of getting the model that includes engine heat. This way I can use the HWH for the intended domestic hot water and use the engine heat loop of the HWH for heating the coach from the HWH. This way the domestic hot water and the heating loop are completely separate. The Suburban brand puts out 12K BTU plus another 4.9K BTU electric element. These are all good options for me to consider. I really like the Martin heater option, I just wish it was the orange radiant glow, instead of the blue flame. At this point, Martin does not offer that option.

Can you please post the part number and the site you got the circulator pump from.

You stated that you connected the heating loop with the engine coolant, so the engine could provide heat. I don't know if you have any need for this, but you could install a second circulator pump in the engine coolant loop. This would allow your heating system to warm up your engine block.

Again, thank you for all your input.
John
'95 Serengeti, Cummins C8.3-300
Allison 6spd.

chuckster
Posts: 59
Joined: Thu Aug 27, 2020 4:53 pm
Location: Meridian, ID

Re: Replace Aquahot heater

Post by chuckster »

Great idea! :idea:
Chuck in Meridian, ID
'01 Safari Zanzibar 3646 (side entry)
Cat 3126B / Allison MD3060
Magnum M-Series "Blue Max" chassis
Owner since 8/2020

Leigh.Calnek
Posts: 6
Joined: Wed Nov 04, 2020 12:48 am

Re: Replace Aquahot heater

Post by Leigh.Calnek »

I need to confess this is the first, and probably the only winter I will spend the winter in the MH. Usually we winter in Mesa AZ or Melaque Mexico. This winter experience is a reaction to Covid, and I am expecting to get my vacination before departure time next fall. Having said that, I would not hesitate a moment to do again what we have done this year. We are currently parked at the Harrison River RV park in British Columbia. We have a 50 amp connection and have only had a few nights where the temp dipped below 0C, and the lowest was -8C. At no time have we been cold, and have used the hydronic heating system the full time for heating the backend of the coach. It has maintained the temp close to 18/19. I do have a ceramic heater in the bathroom that I turn on low on the coldest nights or when we use the shower. The front end is heated by a 1500 watt oil heater and a 750 watt ceramic heater. If we feel cool at night, we use the Martin heater as well. The biggest issue we have had has been condensation on the walls and windows which we solved by purchase of a residential de-humidifier. By placing the output fan on the de-humidifier, it provides a great air movement through the oil heater. In addition to the builtin propane tank on the MH, I carry two 20 pound tanks that are connected through the line at the back feeding the rear heaters. That is, I have a line from the main tank leading to the back where I installed a 4 way connector, one as input, one for each water heater and one to feed an outside cooker or alternatively a line in to back feed the entire system. On the coldest nights (minus 5-8C), we used one 20 pound tank in 5 days

The Martin heater I used was the Martin MDV12. It is advertised as a 12-20KBTU unit with dimensions that would fit the space where the cabinet was located.

The replacement circulation pump I purchased was the Meziere WP136S. I selected this because the input/output are horizontally aligned which was a much better fit given where I wanted to locate the pump. I purchased it from Amazon US and at the time paid $248.39USD and brought it back with me in the spring. We don't use the MH in the states. I see it is available from Amazon on both the CA and US sites, but significantly more if you order in Canada. I found it worth my while to purchase from US and pay the exchange myself.

I love the Girard 2GWHAM on-demand tankless water heater I installed. We basically leave it set at 106F for showering or incidental hand washing. I like long showers and never worry about running out of hat water. On the coldest days, i upped the temp to 107F.

I tried a Suburban (6 gal I think) water heater but it was too deep to fit the space available. Even the Atwood was a very tight fit, and as I recall we had to solder elbows on the input and output lines. I thought about the additional pump for heating the engine, however at the time I didn't see me out in that cold and by the time all the water lines were installed, it was getting too tight.

I hope the above provides a clarification and answers most of your questions. I will post another two messages with some pictures and explanation. I am not certain how many pictures I can attach but we will give it a try.

Leigh.Calnek
Posts: 6
Joined: Wed Nov 04, 2020 12:48 am

Re: Replace Aquahot heater

Post by Leigh.Calnek »

So, it appears I am limited to four pictures in a posting. There is much discussion could develop from these, but I am not sure how useful they are in helping one understand how we did what we did.

After previewing this post, I should reduce the density of the photos which I will do tomorrow. I like the size but would like them to load quicker. So tomorrow I will post some pictures of the Martin heater installation.
Attachments
Not a whole lot to see here.  At the bottom I installed a heat guage so I could monitor the temperature of the heater fluid.  You can also see the hot water line out U which feeds to the front or the back. Clearly, this could have been done better although there is a lot of hoses and wires that were required.
Not a whole lot to see here. At the bottom I installed a heat guage so I could monitor the temperature of the heater fluid. You can also see the hot water line out U which feeds to the front or the back. Clearly, this could have been done better although there is a lot of hoses and wires that were required.
4-LeftCompartment.jpg (4.64 MiB) Viewed 22 times
This is the inside of the left compartment door.  This is where the control connections for all devices and components are found.  For example, on the left and the right are the two relays that control the heater register fans in the front and back of the coach.  The thermostatsfeed the fans through these relays.
This is the inside of the left compartment door. This is where the control connections for all devices and components are found. For example, on the left and the right are the two relays that control the heater register fans in the front and back of the coach. The thermostatsfeed the fans through these relays.
3-LeftDoor.jpg (4.62 MiB) Viewed 22 times
This compartment is directly below the heater units.  You can see the circulation pump located on the left.  Each of the hoses has a turnoff valve on each.
This compartment is directly below the heater units. You can see the circulation pump located on the left. Each of the hoses has a turnoff valve on each.
2B-LowerHeaterCompartment.jpg (5.3 MiB) Viewed 22 times
The full compartment where the AquaHot had been The compartment was lined with sheet metal and lined with cement board.  The Girard Tankless is on the right and the Atwood for the hydronic heating on the left.  At the extreme left is a plywood door covering the compartment where hoses and connections are found.
The full compartment where the AquaHot had been The compartment was lined with sheet metal and lined with cement board. The Girard Tankless is on the right and the Atwood for the hydronic heating on the left. At the extreme left is a plywood door covering the compartment where hoses and connections are found.
2A-UpperHeaterCompartment.jpg (4.96 MiB) Viewed 22 times

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