How To Replace a summer loop pump in a ITR OASIS Hydronic heater

[Neal]

@Neal save your old pump, tear it down and look at the bearing.

A little late, that would be in the prior CG dumpster

 

[turbopilot]

A little late, that would be in the prior CG dumpster

Unfortunately someone will get one soon. Simple tear down should answer some questions.

 

[Rich W.]

I think these pumps are magnetic drive. Here is a good source to understand these pumps. In motor homes they operate continuously to provide "always hot" water. I wonder if it would be a good idea to use a cabin motion sensing switch to turn on the pump anytime motion is sensed in the cabin? I suspect these pumps fail with simple bearing wear. @Neal save your old pump, tear it down and look at the bearing.

They don’t have a bearing - the impeller just floats on the magnetic field. So as far as I can tell, when they fail its electrical - a sealed coil of some sort. You can see in the second pic what happened when I tried to bench test a failed pump “motor” with the impeller out.





Edit - correction (great article btw) There is a rotating shaft in the sealed motor which, according to this article, rides on a bearing or bushing. I can see how that could fail and once it does the motor seizes up and pops fuses, or in the case of applying current on the bench it lets the smoke out.


From the article: “Bearing Wear: In mag-drive pumps, the bearings operate close to the magnets, which can cause increased friction and wear and result in increased maintenance requirements.“

 

[turbopilot]

They don’t have a bearing - the impeller just floats on the magnetic field. So as far as I can tell, when they fail its electrical - a sealed coil of some sort. You can see in the second pic what happened when I tried to bench test a failed pump “motor” with the impeller out.

View attachment 21338

View attachment 21337

Or maybe not so sealed and that is the problem. Coolant intrusion into the coil?

 

[Rich W.]

then there is this:

Dry Run Protection

A principal reason for pump malfunction is operating without fluid, often resulting from human errors or system disturbances. In such situations, pumps may continue to function with no fluid, which leads to rapid deterioration or destruction of the pump in many instances. Nevertheless, specific mag-drive pump configurations can withstand dry operation. In industrial settings where pumps do not receive continuous monitoring, this capability to function without fluid can expressively reduce the likelihood of pump breakdowns and related expenses.

 

[J&JD]

when things stop they gum up, corrode, who knows and don't come back on. It's like we hear....lightbulbs don't die when on, it's the turning on and off that kills them.

I don’t know about that. I usually shut my Cummins engine down when I’m not using the coach. Why would you want the Oasis on if your coach is stored & plugged in. Makes no sense to me. I wonder what ITR suggests. I haven’t read anything on turning the unit on/off when not in use.

 

[MemoriesByTheMile]

We have had our coach for 3 years and it is now 10 years old.
Except when we have done maintenance, we have never turned the oasis off at the control box next to the main green unit. We have only turned it to “off” inside the coach on the panel.
I don’t recall if flipping the inside switch to off stops the oasis pumps from running. Would assume so, but don’t recall.
Interesting thread, continuing to follow as we want to learn to avoid unnecessary repairs.

 

[Neal]

I don't have the manual open but I believe ITR addresses "cavitation" in the pump replacement instructions. If for some reason fluid doesn't flow and the pump needs to prime, or whatever this is under, is documented somewhere by ITR.

 

[Joe Hogan]

Oasis Manual see page 49 for pump replacement procedure

https://itrheat.com/wp-content/uploads/2017/07/Oasis_Service_Manual1.pdf

 

[Kevin D Pem]

They don’t have a bearing - the impeller just floats on the magnetic field. So as far as I can tell, when they fail its electrical - a sealed coil of some sort. You can see in the second pic what happened when I tried to bench test a failed pump “motor” with the impeller out.

View attachment 21338

View attachment 21337

Edit - correction (great article btw) There is a rotating shaft in the sealed motor which, according to this article, rides on a bearing or bushing. I can see how that could fail and once it does the motor seizes up and pops fuses, or in the case of applying current on the bench it lets the smoke out.
View attachment 21339

From the article: “Bearing Wear: In mag-drive pumps, the bearings operate close to the magnets, which can cause increased friction and wear and result in increased maintenance requirements.“

So in the last 2 weeks, what have we learned?
1. The fluid in the system changes Ph! It appears to go acidic.

2. The pump runs all the time.

3. The expansion tank can, or is open to the environment (may lead to fluid contamination).

4. Bearings in motor fail.

We have also learned that many articles, and there drawings are not proofed.

What we or I don't know?

1. What kind of Bearing are used (ceramic would offer longest life)?

2. Is the motor brushless(if brushed no hope)?

3. How often is the fluid replaced?

To avoid misinformation, I would like to dispel, and get us back on track!!! The common refrigerator is constantly turned on and off, and many have seen lives well over 20 years. This is made possible using closed systems. An electric motor has one weak link, the Bearings. In the case of a sealed compressor there are no brushes, and the Bearings are not lubricated with grease. Ceramic Bearing when used require little lubricant.

So how can we increase the life of our system?
With the system as it sits. Check the Ph of the fluid on a schedule. Make sure there are no airlocks. Only run the system when aboard the vessel, or when required. I the pump has any of the above shortcomings, only two things you can do! Find a commercial pump, or reduce the hours you put on it!!! I agree with @Neemer or was that @J&JD there is no reason cycling should reduce it's life.

 

[J&JD]

From page 11 of the ITR troubleshooting manual:

Domestic Hot Water
The call for domestic Hot water is automatic. There is a temperature sensor mounted on the domestic water inlet pipe to the heat exchanger. Once the hot water tap is opened, the domestic water will begin circulating through this heat exchanger. Once the inlet pipe cools below a pre determined temperature range, the distribution module zone board will respond to a call for domestic hot water, as long as it detects that heat is available inside of the Oasis Heating Module. In this situation, the distribution module zone board will turn on the summer pump and will circulate hot coolant through a small loop (summer loop) that goes through the heat exchanger and back to the Oasis. This will allow a constant supply of hot water, whenever the domestic hot water is used.

if I read this correctly, the zone board turns on the summer loop pump only when the domestic water supply temp drops a certain amount thus giving a constant supply of hot water when called for. It does NOT run continuously.

 

[AbdRahim]

That is a good idea, however, there is the counter to that when things stop they gum up, corrode, who knows and don't come back on. It's like we hear....lightbulbs don't die when on, it's the turning on and off that kills them.

Hmm 9 out of ten of my marker lights. Not using Newmar’s anymore.

 

[J&JD]

Here is a copy of a seminar on the Oasis system that might be useful easy reading for many users:

https://www.irv2.com/forums/attachment.php?attachmentid=80983

 

[Neal]

Had a good presentation by ITR (OASIS) at the Newmar Hoots rally. A few items of note:

1. I'm not sure why they call it the summer loop, it is the "hot water" loop. Zone 1 is the forward heating pump, Zone 2 is the aft heating pump, summer loop is for hot water and we should never call it summer loop again and stop enabling this stupidity. ITR - please rename this!
2. I asked the question brought up above about turning off the OASIS at the unit in the basement when in storage. Not necessary, when you turn it off at the panel (AC I/II and burner) then that is all that is needed for storage. Pumps won't run unless there is a need.
3. It may not always be a pump but if you're not getting hot water for example, open the unit with the pumps and in the upper section are check valves, hit them gently with something to cause them to open if they are yucked up. He actually fixed one here that had this very issue. I've never heard of this situation, interesting. Typically a bad pump is associated by a blown fuse so if something is not working and no fuses are blown, try the above.
4. Run your burner to exercise it and don't let it go for extended periods without use. O-rings, etc.
5. You can delay service intervals but should keep a service kit on board if you need something such as an igniter or something when it goes bad.
6. No difference in the orange vs. yellow heater fluid other than the dye they use to color it.

Here is a quick link to the ITR resources on THIS site.

Search results for query: itr

rvforums.com

 

[Neal]

US solar pumps out of stock! Thanks y'all

 

[Just George]

Well, if you need to order a pump now you could go here.

 

[Neal]

Naaah, thanks, I have one more. Was going to hoard some more. I think I may know what my issue is...we'll see how things go tomorrow. Not a pump issue.

 

[Texas Clodhopper]

I think I may know what my issue is...we'll see how things go tomorrow. Not a pump issue.

Hang on Trigger! What are you surmising the issue being?

 

[Neal]

I think the issue going on with my system of late is probably a bad summer loop pump that I replaced two weeks ago. Not touching anything for now but continuing to figure out what's going on with my intermittent hot water. I have another spare I may try if this keeps up. I put in a call to ITR yesterday 3:30 PM their time and have yet to hear back from my voicemail requesting help troubleshooting.

 

[Texas Clodhopper]

I'm not sure why they call it the summer loop, it is the "hot water" loop. Zone 1 is the forward heating pump, Zone 2 is the aft heating pump, summer loop is for hot water and we should never call it summer loop again and stop enabling this stupidity.

O man of exactness, according to your prior post you are perpetuating stupidity. Now, even after chastising you for not following your on rule, it sounds more like a sticking check valve. Is it doing the same thing it was doing before you replaced the "hot water loop" pump?