Can high water pressure confuse your Hydronic heater?

donfrump wrote:
...the big AH 600 series has dual 120V heaters and one almost never needs diesel for heat or long shower unless boondocking

My Oasis has dual 120V electric heaters as well. I never use the diesel and don't see a difference with the AH.

DSDP Don wrote:
I was new to hydronic heating (Oasis) when we bought our 2014 Newmar. It had a little bit of a learning curve. I've learned that the water temperature and furnace use have a big impact on how the unit performs. My unit has two 120 volt electric heaters and the diesel burner. If the water is reasonably warm, the two electric units will give a good hot shower. If the water is cold, the two electric units will not do the job and I have to turn on the diesel burner.

When the water isn't too cold, but we're running the furnace, (radiators are being heated) the shower will again need the extra diesel burner. If the diesel burner is left on, along with the electric burners, we never have an issue, but I don't like to run the burner unless it's necessary, especially when in close proximity to other campers. Mine has no odor, but can be loud. In warm weather, the two electric burners work well.

I know nothing about the AquaHot system, but the ones I've seen are much larger than the Oasis unit in my coach. I'm guessing the AquaHot units are more powerful and probably take less management than my Oasis unit.

that is one thing oasis is known for * odorless* verses the AH
the big AH 600 series has dual 120V heaters and one almost never needs diesel for heat or long shower unless boondocking

I was new to hydronic heating (Oasis) when we bought our 2014 Newmar. It had a little bit of a learning curve. I've learned that the water temperature and furnace use have a big impact on how the unit performs. My unit has two 120 volt electric heaters and the diesel burner. If the water is reasonably warm, the two electric units will give a good hot shower. If the water is cold, the two electric units will not do the job and I have to turn on the diesel burner.

When the water isn't too cold, but we're running the furnace, (radiators are being heated) the shower will again need the extra diesel burner. If the diesel burner is left on, along with the electric burners, we never have an issue, but I don't like to run the burner unless it's necessary, especially when in close proximity to other campers. Mine has no odor, but can be loud. In warm weather, the two electric burners work well.

I know nothing about the AquaHot system, but the ones I've seen are much larger than the Oasis unit in my coach. I'm guessing the AquaHot units are more powerful and probably take less management than my Oasis unit.

holstein13 wrote:

dougrainer wrote:
I believe the tech at Oasis is not correct. I went to the service manual for Oasis units and found that while I am certified on Aqua hot and not Oasis, the systems are very similar in controls. There is NO pressure switch and NO system of any kind that will let the Oasis unit know what the fresh water pressure is. Just like Aqua hot units. In the operating manual and the Service Manual, there is NO spec or anything that brings up pressure for malfunctions. I could find NO spec for minimum water pressure or maximum water pressure requirements. The 120 and Diesel both function from their respective tstats and nothing else will stop their function. I would remove that regulator and test if it still functions. I would also call Oasis and talk to another Tech and ask if the water pressure is true and to e mail the documentation for their statement. The reason I would do this is because something caused your system to fail and I doubt it was water pressure. It was a coincidence that it worked after you installed the regulator. Doug

That's exactly what I suspect. I'm leaving the regulator on for now but if it happens again, I'll know to look further. This is the first campground in 5 years I've ever been to that had decent water pressure.

But, I've noticed that the water is much hotter now that I've installed the pressure regulator. So there may be something to the tech's analysis. I don't think it has anything to do with the pressure, but maybe more to do with water flow from either the water pump or city water connection confusing the tstats.

ALL on demand Hot water systems---the slower the water passes thru the copper heating coil in the tank the MORE heat it receives and brings to you. So 45 PSI is the "norm" for water systems. That is what the non adjustable regulators are set at. So, yes, you will see hotter production and leaving the regulator in place is the right thing to do. Doug

dougrainer wrote:
I believe the tech at Oasis is not correct. I went to the service manual for Oasis units and found that while I am certified on Aqua hot and not Oasis, the systems are very similar in controls. There is NO pressure switch and NO system of any kind that will let the Oasis unit know what the fresh water pressure is. Just like Aqua hot units. In the operating manual and the Service Manual, there is NO spec or anything that brings up pressure for malfunctions. I could find NO spec for minimum water pressure or maximum water pressure requirements. The 120 and Diesel both function from their respective tstats and nothing else will stop their function. I would remove that regulator and test if it still functions. I would also call Oasis and talk to another Tech and ask if the water pressure is true and to e mail the documentation for their statement. The reason I would do this is because something caused your system to fail and I doubt it was water pressure. It was a coincidence that it worked after you installed the regulator. Doug

That's exactly what I suspect. I'm leaving the regulator on for now but if it happens again, I'll know to look further. This is the first campground in 5 years I've ever been to that had decent water pressure.

But, I've noticed that the water is much hotter now that I've installed the pressure regulator. So there may be something to the tech's analysis. I don't think it has anything to do with the pressure, but maybe more to do with water flow from either the water pump or city water connection confusing the tstats.

holstein13 wrote:
I've got an Oasis hydronic heater in my coach and today it malfunctioned. I went to take a shower and I had no hot water.

I got out of the shower and checked to see if the burner was turned on. Both the electric heating elements and the burner were set to come on but were not coming on despite the low temperature of the water. So I called Oasis.

When I got tech support on the line, the guy on the other line first had me describe the problem for him then he asked me to turn on the summer bypass loop and see if that would fire up the heater. Sure enough, it did.

Then he asked me if I was hooked up to city water. When I told him that I was, he immediately said my water pressure is too high. According to him, the Oasis is designed for water pressures under 55 PSI and if the pressure is too high, it confuses the heater.

Therefore, I screwed on my pressure regulator and have crossed my fingers to see if he was correct. So far, so good. Have any of you ever heard of such a thing?

I believe the tech at Oasis is not correct. I went to the service manual for Oasis units and found that while I am certified on Aqua hot and not Oasis, the systems are very similar in controls. There is NO pressure switch and NO system of any kind that will let the Oasis unit know what the fresh water pressure is. Just like Aqua hot units. In the operating manual and the Service Manual, there is NO spec or anything that brings up pressure for malfunctions. I could find NO spec for minimum water pressure or maximum water pressure requirements. The 120 and Diesel both function from their respective tstats and nothing else will stop their function. I would remove that regulator and test if it still functions. I would also call Oasis and talk to another Tech and ask if the water pressure is true and to e mail the documentation for their statement. The reason I would do this is because something caused your system to fail and I doubt it was water pressure. It was a coincidence that it worked after you installed the regulator. Doug

bullydogs1 wrote:
The complexities of all these systems never ceases to amaze me...see if under 55 and it stays good...then if you have some time, try it over 55 ....and if same symptoms, then they are right...while I have good friends with an Entegra I've helped with an aqua hot..your unit is different..at least you got help when you needed it...Safe travels.

Never worked on an Oasis unit. But, from the Oasis response, it MUST have a internal pressure sensor that senses hi water pressure and shuts down the unit. The reason it will do this is like the Aqua Hot systems(they do not have such a sensor), if you flow the water too fast thru the Heater copper coil, it will not pick up the heat transfer and you will get cool water. Aqua hot you will just get cool/cold water. Oasis, obviously will not function until you fix the supply problem. I personally do NOT like built in water pressure regulators. Much better to use your OWN and install at the water spigot to prevent hi pressure from ruining your own supply hose. Doug

holstein13 wrote:

DSDP Don wrote:
Okay, my Dutch Star didn't come with a water regulator and I added an adjustable one......but your King Aire didn't come with a built in regulator???

Nope, no built in regulator.

I'm also surprised you didn't have a regulator but now you do! Probably 99% of the time shore water is not super high.... it's just the 1% of the time that it could cause a problem.

We had such a problem when we had our '08 Dynasty. The shore water at a Utah campground must have been super high. Even though we had a regulator, I was getting water forced passed the 'red hat' valve and it was filling up my fresh water tank making it over-flow. I also found a couple of leaks at the screw-on piping, so I tightened them and it stopped. Not sure how the pressure got beyond the regulator but it apparently did.

The Liberty uses water from the fresh water tank only. Maybe that's not a bad thing as I'll never have a high pressure issue. The only time shore water is used is when we need to refill the fresh water tank. The negative would be if my water pump went on the blink, we couldn't pull in water from the shore connection.

Glad that you got it worked out!

Have a fun, prosperous New Year and safe travels!
MM.

The complexities of all these systems never ceases to amaze me...see if under 55 and it stays good...then if you have some time, try it over 55 ....and if same symptoms, then they are right...while I have good friends with an Entegra I've helped with an aqua hot..your unit is different..at least you got help when you needed it...Safe travels.

DSDP Don wrote:
Okay, my Dutch Star didn't come with a water regulator and I added an adjustable one......but your King Aire didn't come with a built in regulator???

Nope, no built in regulator.