FYI What does that green light mean? (OASIS AC I/II)

[Neal]

For those with the panel above the entry stairs with the AC I - OFF - II there is a green LED (diode) next to the switch. Some think that when the green light is ON then OASIS is on and doing it's thing. This is not true and something I believed for a while as well until all of the electrical issues I had with my OASIS which afforded me the opportunity to better understand the system.

Take the scenario of those that want to have the furnace on while driving to provide heat. Some have said to just turn on AC I which will show you the green light and that will provide heat. That is NOT true. What is actually providing heat is the engine heating the hydronic fluid (anti-freeze). In order for AC I / II to work you must have 120V power either from shore power or the GEN.

So what does that green light mean?

In your OASIS "green box" are 3 relays for each electrical element and the diesel burner. A relay allows a low power signal to open a circuit for a higher power path. So in the case of this "green light" the switch up front is only sending a 12V signal to the relay(s) in the OASIS unit closing the bridge per se so that 120V current can pass through, if available. The green light is only indicating that the 12V signal is being sent to the relay to "open" and allow 120V current to pass. It does not indicate anything is running, on, available to provide heat. When OASIS is running and passing current (120V) to the electric elements you will see the other green light on the right side of the panel near the fault light, burner green light, etc.

There are a lot of misconceptions out there and I hope this helps better understand the OASIS system for some. I read a lot of the chat in the RV Facebook groups and it's concerning how many don't really know their RV systems and it took me a long time to learn as well. The education channels are simply not there to learn from and forums like this is one of the better sources of info share.

If you know of a system that is not well understood and you see discussions out there that get your attention, please consider educating others by posting content such as this to help each other better understand their coaches and systems.

 

[Rich W.]

Thanks Neal. I find I have to re-learn a lot of stuff nearly every time I take the coach out since it usually sits a couple months between trips. And I agree about the Facebook RV groups - I’ve tried but there is so much that is so wrong and so many responses to everything that I quickly got overwhelmed. There’s just too much volume that’s too wide of the mark for me to get involved.

But back to the topic, I‘ve been told and was under the impression that you had to have the Oasis system “on” to avail yourself of engine heat while driving and turning on AC (I or both) would close the necessary “bridges” to do so. It sounds from your treatise that you need do nothing but drive and heat will be available. And it makes sense that triggering a relay with 12v dc wont do anything if there isn’t 120v ac to cross that closed bridge. This would also explain why there is always hot water when we arrive somewhere, after doing nothing with the Oaisi as far as I can recall. And of course there is an on/off switch on the unit, so as long as this is on you’ll have heat underway? Am I getting close?

 

[J&JD]

And of course there is an on/off switch on the unit, so as long as this is on you’ll have heat underway? Am I getting close?

Sounds correct to me.

 

[Suburbazine]

It's probably better to describe the green light as the "burner armed" light. Just means the burner is allowed to ignite, not that it is ignited.

AC light indicates AC relay status, but in this case it means the heater in actual heating stage... But not that it's actually heating if there's no AC power to the coils.

Burner light green = burner armed
AC light green = furnace demand active

If a detectable fault exists you get the red fault light.

I've asked ITR to make this less confusing by changing light state so it follows actual operation, but they said it would require reprogramming the burner logic and it's too much trouble. I also wanted to get an electric-only maintenance heat mode (2 stage heating) so the burner doesn't run every time the fluid needs heating but there's no real demand. Maybe if more people ask...

PS: not every Newmar has Oasis plumbed to engine. So some of them do require the furnace to operate for heat.

 

[Neal]

so the burner doesn't run every time the fluid needs heating but there's no real demand

I can only speak for mine but if there is no demand (i.e. hot water running) then the burner/elements will not run. You can see this situation by watching the green light (burner active) on the right side of the control panel. It will not come on unless you run the hot water. You also need to know this to test your electric elements as you won't see the amp rise unless you are triggering a demand by running hot water at the sink.

How To - Verify your ITR OASIS Two Electric Burners are working

In my other thread about AC Heat not working I had a short, a second electrical short in the wiring of my OASIS system. In verifying the wiring ITR Heat had me go to my EMS panel and then turn AC I on and check for an AMP change. I showed +12 AMPS. Then switch to AC I and II and you should see a...

rvforums.com

 

[Suburbazine]

I can only speak for mine but if there is no demand (i.e. hot water running) then the burner/elements will not run. You can see this situation by watching the green light (burner active) on the right side of the control panel. It will not come on unless you run the hot water. You also need to know this to test your electric elements as you won't see the amp rise unless you are triggering a demand by running hot water at the sink.

How To - Verify your ITR OASIS Two Electric Burners are working

In my other thread about AC Heat not working I had a short, a second electrical short in the wiring of my OASIS system. In verifying the wiring ITR Heat had me go to my EMS panel and then turn AC I on and check for an AMP change. I showed +12 AMPS. Then switch to AC I and II and you should see a...

rvforums.com

If you leave the unit on, it will cycle intermittently to maintain fluid temperature. Hot water is dependent on hot fluid, it's not heated directly by burner or electrics. These intermittent heating cycles mean if the diesel burner is armed, it runs every time the fluid needs to reheat.

 

[Neal]

Makes sense, I think there has to be some threshold of keeping the heater fluid from getting too cool. But a demand such as turning hot water on or furnace running triggers it.

 

[Rd1]

.......
But back to the topic, I‘ve been told and was under the impression that you had to have the Oasis system “on” to avail yourself of engine heat while driving .........

If I understand your question, you are stating with the engine running would the oasis produce heat? The simple answer is NO, unless the burner is turned ON. ACI or ACII ON will not produce heat.

Now, you state you have hot water with engine running. That is true. The engine coolant will heat the oasis heat exchanger (no matter what state the oasis is), so there will be some temporary hot water, even with the oasis burner OFF. However, if you took a shower, you'll quickly find out the water will turn cold in short order.

The heat exchanger hold 1 qt of water more or less and remains hot for a period of time. However, as more cold water run thru, it'll turn cold.

The oasis burner must be on for oasis to produde continious hot water as well as heat inside the coach. If the engine coolant is not hot enough, the burner will run. Once the coolant is hot enough, the burner will not be running anymore.

 

[MemoriesByTheMile]

The oasis burner must be on for oasis to produce continuous hot water as well as heat inside the coach. If the engine coolant is not hot enough, the burner will run. Once the coolant is hot enough, the burner will not be running anymore.

I haven’t tried this scenario to see if the Coach engine running can make the oasis produce heat.

Seems that when the engine is running - and if you have the loop pump for preheating the engine — that the engine coolant would be hot enough to make the oasis produce heat. This has me curious and will need to test this out the next time we hit the road, but that isn’t planned to happen for a few months.

How many have the loop pump for the “engine preheat”? Is this common or relatively obscure?

 

[team bradfield]

How many have the loop pump for the “engine preheat”? Is this common or relatively obscure?

Mine has a space for a rocker marked engine heat, but has a blank cover, no switch, so I assume mine does not have the preheat option

 

[Rich W.]

Mine has a space for a rocker marked engine heat, but has a blank cover, no switch, so I assume mine does not have the preheat option

That is correct and also typical. You can add it but if you have a block heater its not needed.

 

[MemoriesByTheMile]

That is correct and also typical. You can add it but if you have a block heater its not needed.

Cool part about this feature, the engine can be heated pretty quickly, without having to leave the coach and plug in a block heater. And when driving, the oasis heats up the domestic water very quickly. So quickly that it raised this question in my mind if the coach engine heat would be enough to heat the coach while driving. Will test it at the end of March on our next planned trip.

But agree it isn’t needed just another nice feature.

 

[Rich W.]

I’ll test it tomorrow. Got a little over 600 miles to drive in the next two days. So. We’ll see what we see.

 

[Rd1]

I haven’t tried this scenario to see if the Coach engine running can make the oasis produce heat.

Seems that when the engine is running - and if you have the loop pump for preheating the engine — that the engine coolant would be hot enough to make the oasis produce heat.

The engine coolant is designed to heat the oasis heat exchanger, provided the oasis burner is ON. On the left side of the oasis distribution box you have the heat exchanger. The brick sized copper unit. It has 3 chambers. One for fresh water, next to it is the chamber for oasis fluid, which is nonpoisonous, the far away chamber is for the engine coolant, which is poisonous. The 2 red hoses on the left side are IN/OUT hoses for the oasis fluid. The 2 black hoses on left behind the red hoses are the engine coolant IN/OUT. Hard to see in the pic.

As for the oasis loop pump to preheat the engine. That is an option, which most do not have. There already is an engine block heater. For higher models, there is just a button on the Silverleaf to activate the block heater, no need to go outside.
To use the oasis loop pump to preheat the engine block, you need to have the oasis running, so you already have heat in the oasis. The optional oasis block heater is a 2 way system. Use oasis to pre-heat the block, and once the engine is running hot enough, then use it to heat the oasis.