As noted in this post…
…I got a call yesterday from an individual at International Thermal Research (ITR), the company that manufactures the Oasis hydronic heating systems installed by Newmar.
While on the phone with him discussing fuel lines, I noticed some low level noise that appeared to be coming from inside my Oasis unit. My first thought was that Amy or I had inadvertently left an Oasis-related switch on inside the coach when we returned home from our most recent trip. I went inside the coach and verified all the Oasis switches were in their off positions. Checked a number of other things, all to no avail. Tried shutting off shore power to the coach which had no effect (nor did I expect it would).
While trying to figure out what was going on, I noticed a display panel mounted on the forward wall of the basement compartment in which the Oasis unit is located. ITR calls that panel a Zone Board – see the first of the photos below. Looking at my panel, I saw lights illuminated for Power, Summer Loop, Heat Loop 1 and Heat Loop 2. Those lights confirmed my suspicion that what I was hearing was one or more circulation pumps running. The good news is that the pumps are pretty quiet. The bad news is that because they’re so quiet, there is no telling how long this issue would have been present had I not discovered it yesterday.
After shutting off shore power to the coach, I tried powering off the Oasis unit using the Power button on the front of the unit. The power down button seemed to work, but the noise was still present indicting the circulation pumps were still running. And the same lights on the Zone Board were still on. Since all else had failed, I tried shutting off 12-volt power to the coach using the Battery Disconnect switch on the panel above the entry door. At that point the noise stopped and the lights on the Zone Board went out.
While all that was going on, I was exchanging text messages with the individual at ITR who called me about the fuel lines referenced in the post linked above. After I told him I'd been able to stop the noise by killing 12 volt power to the coach, he responded saying he had a strong suspicion as to the cause of my problem and would call me when he had time.
He called this morning (Tuesday 6/21/2022) and told me to locate the “Bypass Switch” on top of the plastic box that houses the Zone Board mentioned above. You can see that switch in the second photo below. He explained that when the Bypass Switch is in the on position, the pumps inside the Oasis unit will run continuously. He went on to say that the coach manufacturers usually turn the Bypass Switch on when filling the system with boiler fluid to ensure the fluid circulates throughout the system, eliminating any air pockets or bubbles. And he added that sometimes the relevant individual forgets to turn the switch off after filling the system.
I was walking our fearless guard dog Grover when he called, but told him I’d check the Bypass Switch as soon as I got home. I did and yes, it was on. Turned it off, restored 12 volt DC and 110 volt AC shore power to the coach, and confirmed the unit was silent; i.e., no circulation pumps running. Also confirmed the Summer Loop, Heat Loop 1 and Heat Loop 2 lights on the Zone Board display were out.
Looking at the location of the Zone Board enclosure box and the Bypass Switch in particular, I concluded there is virtually no way the switch could have been turned on by accident. So the open question is whether:
1) The switch has been on since someone at Newmar turned it on to fill the Oasis system with boiler fluid,
2) Newmar sent the coach out with the Bypass Switch off but someone at our selling dealership (Sport Truck RV here in the Phoenix area) turned it on.
Sport Truck RV is a relatively small dealership and has only one coach-related tech. His primary job is to ensure new coaches are ready for delivery. As such, I highly doubt he would have done anything with the Oasis system other than to turn it on from the panel inside the coach, just to ensure it was working.
As I said to the guy at ITR, if I have ten dollars to bet I’m putting $9.98 of it on Newmar as the party that left the Bypass Switch in the on position. But I am checking with the guys at Sport Truck to see what they may know.
In case any of you are interested in the math, our coach was completed at Newmar on 2/14/2022. Generously assuming that filling the Oasis system was one of the last things they did, the Oasis pumps had been running for over 3,000 (yes, three THOUSAND) hours before I turned the Bypass Switch off this morning. I have no idea what the estimated useful life of an Oasis circulation pump may be, but I’m pretty sure a fair amount of that useful life is down the proverbial drain at this point!