Oasis Issues Resolved!!

Main Controller Unit
Main Controller Unit

If you have been following along you will remember that we have been having problems with the Oasis system on the Ventana.  Oasis is the brand name for the hydronic heating and hot water system on the all electric coach.  It not only provides hot water but also baseboard heat as a furnace once it gets too cold for the heat pumps to function efficiently.  It is a great idea and for most folks, I understand it to be fairly trouble free.  Well, not for us.

Since we took delivery of the rig in October, I felt that something with the system was not working properly.  When I used the furnace, it seemed like the fans ran a long time and would blow cold air on occasion.  I mentioned it to the techs at Newmar, but when they tried it it worked fine.  Well, the almost continuous fan running and occasional blowing of cold air continued so I took it to the dealer in Jacksonville.  They kept it for a few days and couldn’t find a problem.  They told me that I was too impatient and that I needed to give the fans time to cycle off once the heat turned off.  I told them I disagreed, but they just looked at me as if I had two heads.  During this time we always had hot water for the shower, dishwasher, etc.

We then left on our trip to Ft. Meyers before Christmas and since the weather was warm we never tried the Oasis furnace.  Once we got to Texas and had some cold nights we used the furnace and again the same thing happened with the fans running almost continuously.  We did get heat and since we were 300 miles from the closest dealer, I told Liz we would just work through the problem and address it once we got back home.  Most of the time we could use our heat pumps anyway.  Well, then all of a sudden we lost all our hot water.  Not Good!!  The problem now became more serious.  I went to the control box and flipped the pump bypass switch which turned all the pumps on and we had hot water.  The only problem was that it also circulated hot water through the heat exchangers inside the coach.  If i didn’t call for heat the fans never came on so it wasn’t too much of an issue as far as getting the inside of the coach too hot.  We just turned the bypass on when we needed hot water for a shower, etc.

Distribution Module
Distribution Module

Newmar was closed as it was late afternoon so I called Oasis directly.  I have to say that these folks are extremely helpful.  I talked to Kevin and explained the hot water problem and he walked me through some diagnostics that led him to believe that it was a faulty auquastat sensor on the summer loop which provides hot water when the furnace loops aren’t active.  He said that it was easy to change and that he would send me a new sensor.  At that point I didn’t bring up the fan issue.  I thought one problem at a time was enough.  I just wanted to get the hot water working properly again.

Auquastat Sensor
Auquastat Sensor

I got the part a few days later and knew that it needed to go in the “distribution module” which is buried in the middle of the coach behind one of the pull out trays.  A carpeted partition board needed to be removed to allow access to the front panel of the module.  It couldn’t be accessed directly from the bay it was in because of the slide out tray which could not be removed.  Consequently, we pulled the adjoining bay tray out the opposite side of the coach which allowed access to the module from the side.  Then it was possible to squeeze

Zip Tie Sensor
Zip Tie Sensor

into the appropriate bay behind the other tray which was pulled out.  Sounds complicated, but it wasn’t.  Unfortunately, I quickly discovered that with the trays in, I couldn’t squeeze my rotund body in close enough to get the screws out of the front panel of the module.  As much as I tried, i just couldn’t get close enough to reach all the screws.  I won’t post a picture of the bruises the “squeezing” created on my chest and stomach.  Just trust me – it was bad.  Thank goodness Liz was able and willing to squeeze into the space.  With me coaching and her using the screw driver we got the panel off and identified the sensor location.  I won’t go into all the details, but we got the sensor off and replaced.  The connections were extremely tight and required the use of two sets of pliers to pull the wires apart.  The sensor is secured with a zip tie, believe it or not, and we needed to be careful to get it on properly so it wouldn’t slip off.  Once the sensor was on, we had hot water again!!  It was a total team effort.

Since I had such success, I decided to call Kevin back and see if I could solve the problem of the heat exchanger fans running so long and the fact that they would blow cold air much of the time.  Before I called, I did a test where I turned each zone on individually and then

Liz at Work
Liz at Work
Distribution Module Pumps
Distribution Module Pumps

both zones on together.  I found that when I turned zone 1 or 2 on individually via the thermostat, the fans would come on but there would be no heat.  the fans would not shut off either since there was no heat and the temperature never increased to satisfy the thermostat.  However, when I turned both zones on together, I would get heat.  I explained this to Kevin and he thought for a minute and said, “Let me call you back after I ask a couple people here what they think”.  He called back in about 15 minutes and said that they think that the zone loop pumps are wired backwards.  He says that when I am asking for heat in zone 1 the fans are coming on in 1, but the hot water is being circulated in zone 2 and vice versa.  So when I ask for heat in only one zone, I get cold air, but when I ask for it in both zones both pumps are working so I end up getting heat.  However since the fans are synched with the thermostat and not the loop pumps the heat in one zone goes off, but the fans keep running as the thermostat is telling it it still needs heat.  Kevin said that all we need to do is switch the wires on the two loop pumps and everything should be ok.  Easy for him to say as that means another trip down under for Liz!

Well, we went through the process again of getting in the bays and changing the wires.  It was a little harder that just switching them as they were extremely tight and needed the use of pliers again.  I was worried that we would end up pulling a wire out of a connector and then we would have another issue to deal with.  Luck was on our side and the switch worked.  Voila!! The heat is now working as designed an the world is once right again.

 

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