There are lots of threads on Oasis pump changes which helped me a LOT in recently having to change my summer loop and zone 2 pumps. But one thing I did not understand going in was the hydronic fluid flow directions or how fluid flowed through the system to be sure I knew what to clamp off, etc. So I thought I would post a few pictures of my recent change out to illustrate to anyone who, like me, might be a little timid on attacking this project, to help alleviate the fears. It really is not too bad of a project, except for being jammed into a "cave" while you do the work!
I am not going into diagnosis of pump failures since that is covered already in many other posts.
The pictures are of a CH50M model Distribution Module with two zones.
This first picture is of my system with the hydronic fluid flow directions noted, which pumps are for which operation, and three backflow preventers to will keep fluid pushed from the pumps from draining back.
Those preventers help a LOT when changing the summer loop and zone 2 pumps as the outbound connector hose is VERY short and cannot really be clamped off, but it doesn't need to be because the backflow preventer will keep fluid from draining from above the pump. While the zone 1 pump also has the feature, the connecting hose is significantly longer, so to minimize a mess, I will clamp that one off if I ever need to change that pump. That said, you could change a pump without much fluid loss with only one tool to clamp off the hoses carrying fluid into the pump.
Before I started my project, I used a tip someone else posted to run the system for a while to get the hoses warm. This will greatly aid in getting hoses off the pump nipples and clamping the inbound hoses off to prevent fluid loss. Be careful though as the hydronic fluid is HOT. I ran the system, then let is cool a bit until I could feel the hoses were still warm, but not hot.
NOTE: Once heated, turn off the system and TURN OFF THE SALESMAN SWITCH TO CUT DC POWER TO THE UNIT. PUMPS CAN CONTINUE TO RUN IF THERE IS POWER.
Many posts talk about how expensive the ITR OEM pumps are and that they tend to fail rather rapidly. I followed the suggestion of others and ordered my pumps from US Solar for about 1/3 of the cost of the pumps from ITR.
One note of interest. ITR uses two different pump part numbers. Not being too bright, mechanically, I failed to see the difference until I was into my project. On the ITR pumps, the summer loop pump has the outflow nipple on the opposite side from the way the zone pumps are. While this doesn't affect function, it does make the zone 2 pump replacement with the US Solar pump a bit more difficult as it moves the pump further into the box which creates interference with other hoses in the distribution box.
Here is a picture of two ITR pumps and the US Solar pump to show the nipple placement difference.
The top pump is the ITR Summer loop pump and the bottom pump is the US Solar pump. They are identical as to the outflow nipple position (the one sticking up) on the pump side.
The middle pump is the ITR zone pump. Note the outflow nipple is on the other side of the pump. The picture is as that pump would be mounted in the box picture shown above. The nipple position to the inboard side move the pump "out" toward the front of the distribution module and provides an amount of clearance from the other hoses in the box. Further pictures will show that I had to change the short piece of connecting hose on that pump to a little longer piece to allow it to be bent outward some to make clearance. I think this would be much less of an issue on the zone 1 pump and it's certainly not a deal-breaker issue from using the US Solar pumps all the way around.
I always love that Newmar nor many of its vendors attempt to keep a consistent wire color coding system. The 12V US Solar pump will have a red and black. The ITR distribution box has a number of colors that don't match the colors from their pumps. The connectors, however, were done so that you can't connect to the wrong wire. Just make sure you duplicate that when you install connectors on the US Solar pump, which only comes with a bare wire end since they have no idea what kind of connector may be needed. I took a picture in advance to make sure I put the connectors on correctly since I can't even remember why I got up from my easy chair to go to the kitchen anymore!
I chose to just reuse the connectors already on the ITR pumps. I just clipped them off, stripped insulation, and used small wire nuts and an electrical tape covering to connect them to my US Solar Pumps.
Removing and reattaching pumps:
Removing the pumps with the hoses warm was really much easier than I thought it would be.
First I clamped off the incoming fluid hose. I happen to have a SIL who has every tool imaginable from his 20 year experience with diesel repair (and anything else that moves). I borrowed his hose pincher clamps. But if you have to buy them, low cost ones with enough functionality to do the job can be had.
I used a bunch of old rags to capture the very small amount of fluid that came out as I first removed the outflow nipple from the short hose that is attached to the backflow preventer. In my case a little side to side wiggling and it came right off. Then I pulled it off the inflow hose.
Backing out of the "cave" I was working in, it was a relief to my aching back to take the removed pump to my workbench to do the wiring connector work!
I then crawled back into the "cave" and reinstalled the hoses and connected the wiring. In my case, the hoses there still looked good, so I did not change hoses. Original clamps also used. One pump done!
The Zone Pumps are mounted to brackets but I was advised that for the US Solar pumps those could just be removed.
The zone 2 pump has screws through the side to hold the mounting bracket, as seen in the first pic below. The pump then has two screws with nylok nuts on them holding the pump to the bracket. I'll leave it up to you which order you want to do removal. I removed the pump from the bracket first (that back nylok was a treat to get out), then removed the bracket screws and pulled it out, then pulled out the pump (after clamping off the incoming line). There isn't a lot of room between the bottom of the bracket and that zone 1 pump so I wanted to get that out of the way to allow a bit more space to pull down the pump. Just the way I did it, not saying it was the best.
Note different wiring color....
Also note how that nipple position has the pump out a ways to provide clearance from other hoses for the inbound hose to this pump.
After giving my back another break and getting the wiring connectors installed on that pump, I crawled back into the "cave" and found out that the original short piece of hose would not allow installation of the US Solar pump as the inbound hose to the pump could not be bent around the other hoses and connect.
I removed that short piece and fortunately I had pre-purchased a small length of 1/2" ID Gates Green Stripe HD heater hose as a Just-in-Case I needed to replace any hose. I cut a piece a bit longer so it could provide some flexibility to bend the pump out and provide some clearance for the inbound hose. Back in the cave...new piece too long....back out of the cave to recut.
After a little finagling, the fit was there. The hose clamps were changed because the Gates hose was just a tad larger in OD than the original hose and no matter how hard I tried, even grinding down the little tab on the clamps, they would not fit on the gates hose.
Now...one potential issue is these hoses rubbing together and abrading. The picture doesn't have it, but I have since installed some heater hose protective loom to avoid future issues.
With the install done I fired the system back up and VIOLA! Zone 2 heat and hot water and best of all NO LEAKS! Yee-haw!!!!!
Hopefully my experiences with this project and the pictures will help anyone that wants to tackle this project on their own. The two pumps cost $165 vs what would have been $500 from ITR. Labor cost....some advil and a Mich Golden Light chaser for my back vs waiting six months for a service appointment in today's environment plus what would have probably been several hours of charged labor time from a shop. Net...a HUGE savings in the relatively easy DIY project.