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

[Neal]

I believe this pump in particular never stops running as long as it has 12V power. And maybe that's part of the problem, which of these pumps run non stop until death?

 

[DennisT]

That is how I understand it as well, summer loop pump runs continuously.

Will be interesting to see how long ours lasts being full time in the coach since we picked it up in December last year.

Maybe I should order the replacement now for the inevitable…

@Neal - when you replaced yours, was there enough room to add a couple shutoff valves? Seems like that would make it easier to replace should it happen again. No need to clamp the hoses, etc.

 

[Neal]

As you can see in the picture some hoses are long, some are short and I'm not sure of the various on/off valves but there is going to be fluid in the line regardless. All pumps are off when you disconnect the cable from the electrical panel.

Yes - everyone should definitely carry at least one spare pump. It will fail and you won't be happy without heat or hot water as they know when you need them

 

[Kevin D Pem]

I don't think they can ever run dry - its a sealed system. You always have to clamp both hoses to R&R a pump and you still get coolant spilling out. I think they are always primed just by gravity, running or not.

But something to consider, as replacement could allow formation of an air trap. Just something to consider.
The installation of a valve at any high spot may avoid premature failure!!!

 

[MemoriesByTheMile]

We have not had a pump failure (knock on wood), but after some experience with the oasis, I wonder about the air pocket question.

A few times (2 or 3 years ago) I heard a surging sound. After some investigation found that the fluid level was a little low in the oasis unit. Added some fluid (pumping from the overflow container that was very full) and forced all pumps on until all air bubbles stopped appearing (took 5-10 min).

Had to repeat this a few times over the following months whenever I heard the surging sound.

Finally discovered the “straw” in the overflow container was drawing air. As a result the oasis heating would cause fluid to expand and go into the overflow but when cooling it would not draw fluid back into the main exchanger.
Once I fixed that straw issue we have not heard anymore surging and the fluid level never drops.
I wonder how many units with summer pump failures are due to air in the lines?

 

[Rich W.]

We have not had a pump failure (knock on wood), but after some experience with the oasis, I wonder about the air pocket question.

A few times (2 or 3 years ago) I heard a surging sound. After some investigation found that the fluid level was a little low in the oasis unit. Added some fluid (pumping from the overflow container that was very full) and forced all pumps on until all air bubbles stopped appearing (took 5-10 min).

Had to repeat this a few times over the following months whenever I heard the surging sound.

Finally discovered the “straw” in the overflow container was drawing air. As a result the oasis heating would cause fluid to expand and go into the overflow but when cooling it would not draw fluid back into the main exchanger.
Once I fixed that straw issue we have not heard anymore surging and the fluid level never drops.
I wonder how many units with summer pump failures are due to air in the lines?

Great tip - I’ll have to check that - guess everyone should.

 

[turbopilot]

I believe this pump in particular never stops running as long as it has 12V power. And maybe that's part of the problem, which of these pumps run non stop until death?

Pump is rated at 20,000 hours which is 833 days. I seem to recall there is a way to turn it off with the coach is otherwise powered. I only ran my Summer loop only when the boiler was actually making hot water. Never had a failure.

 

[J&JD]

When not using the rv, stored , not in use etc, turn off the system with the switch on the front of the unit.

 

[Neal]

When not using the rv, stored , not in use etc, turn off the system with the switch on the front of the unit.

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.

 

[turbopilot]

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.

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.

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.