Coleman SaluSpa Lay-Z-Spa Pump Casing

Updates
2026-06-06
I got sidetracked working on other projects and since I qualified for a replacement pump I never went back to this project. I recently got a question about the parts so I found my heater casing design and decided to upload it, as is, in case it is of any help to anyone else.
I did redesign the part to print more easily but it required a complete change in water line placement and I do not remember how I was going to alter my hose layout to work. I believe I might have planned to just use the large tubing to create the 90 degree turn using a plastic elbow but I don't recall. I will also upload the new design which replaces the heater end including the flow sensor portion in case it might be helpful for anyone as well. The new design requires the flow sensor flap to have a small neodymium magnet to be glue and sealed on the top as well as a pivot pin to be inserted to hold the flap in place. Then the end hole needs to be sealed to stop water leaking. Ensure the flap moves properly before sealing the pin in place. These parts have not been tested so it is really a design concept rather than a working part. The parts need to be positioned in the casing so gravity will close the flap or the flow sensor will not operate.
In the process of redesigning I came up with single piece design which I did not quite finish. I still have to locate the STL for that design but I have uploaded a photo that shows the new design. I believe the flow sensor flap and magnetic switch attachment were not yet completed for that last design. When I locate my files for that one I will try and upload it as well.

2025-06-20
I am still struggling with the main heater flow cartridge. I have tested the silicone gaskets I made on the return end of the heater and they seal it pretty well. The problem I am running into is the large ABS print that attached to the other end of the heater. I have been able to print a couple of tests in ABS but they warp too much and then are unable to seal against the aluminum extrusion. I am currently printing without a good enclosure (just covered my printer sides with some cardboard) and I notice the part warping and pulling away from the build plate. I tried redesigning the part to work as a single print but so far I have not had success at getting a print that will work so far. I may end up moving my printer and building a proper enclosure for it. That may help. An alternative is to do a test print in PETG and then seal it like I did the pump cover. I am also thinking that the easiest gasket seal method would be to use some silicone gasket material (automotive or high temp) and just apply it to the surfaces before tightening them together. That would probably handle the imperfections in the surfaces. I think the only problem with this would be applying too much and having it forced into the water chambers. I have also designed a new descaling tank that has a bottom drain and has the threads for the connectors built in. Still need to make a closed plug for the drain hole. I'll upload those when I have them completed.

2025-06-08
I have made a few silicone gaskets but I have not been able to test them yet. I have also completed my heater flow cartridge prototype and printed it in ABS. I made it in two parts that get glued together in order to ensure that the sides where there are seals are as flat and accurate as possible. I split the model so that the base that attaches to the heated can be printed flat on the build plate to retain its fine detail. I also wanted to limit the amount of supports so the design has that built in along with the print orientation. Once I have tested it I'll upload the STLs. For now I have included a photo.

2025-06-05
Just playing around while I work on my heater cartridge design and have a couple of untested parts. The first is a heater gasket mould for liquid silicone. I have no idea if it will work or not but thought it would be fun to experiment with. I have ordered some silicone for testing it out but waiting for it to arrive. The other is a 3D printed container for the de-scaler. I did print one using ABS which printed well except for a few layers where slight warping split them apart. I did repair them by sealing the part with ABS juice and I did attach the connectors and fill it with water. It does not appear to leak. You can actually see one of the split lines in the white portion of the print.

2025-06-01 #2
I just tried using one of my TPU gaskets on the recirc end of the heater block. I found that 2 sets of the channels held water but the one set, on the outside, leaked. I believe it is due to the amount of corrosion on the surface where the gasket mates with the aluminum case. I will try to smooth it down but I think the pitting is way too deep. I am also wondering how the TPU will handle the heat from the ceramic heaters in the aluminum extrusion. I am not sure how hot they would get at the ends. I might have to use some high heat silicone liquid gasket material. I could also make silicone gaskets by creating a mould from my gaskets. I did something similar to make silicone socks for my printers.
I am pretty sure that the original gaskets had been leaking for some time based on the residue on the heater and the plastic ends.

2025-06-01
I was working on a new design for the heater cartridge and was thinking that I would need some way to test the system without having the actual tub available. I saw that some people had de-scaler tanks which you attach in place of the tub and fill with water and some descaling chemicals. It then just recirculates through the heater unit.
I thought that one of those de-scalers would work nicely but found that it would cost me over $60 to buy one. Instead I designed and printed a 2 couplers that I could attach to some kind of flat sided plastic container. I was sure I had something lying around that could use. Just cut two holes in the side of the container at the proper spacing and remove the top (so you can get your hand inside,) slide the couplers in place and then tighten them in, using some gaskets (I used some 'O' rings I had)
When I went to look for a container large enough all I could find was an old Kirkland Olive Oil container in the recycling.
I printed the couplings out of ABS ( I stuck some cardboard around my printer to make a quick enclosure so I am able to print ABS now.) I checked the unit for leakage and everything worked fine. I still have to get my other part printed before I can actually test this out, so let me know how it works if you make one.
Since the container is just thin plastic its a little flexible. I might just print a slightly thicker container out of ABS if I end up not liking the thin plastic. I made the connectors long enough so they can fit a thicker walled container. The couplers are designed to be printed without supports and are designed to fit in a specific direction. It should be pretty obvious.
I am currently doing a test print of the new heater cartridge so I am crossing my fingers. I am also printing it using ABS.

2025-05-28
When the impeller arrived I installed the new unit and did a quick leak test. Water started dripping so I thought it was my new part. On closer inspection it looked like the new casing was not the issue.
I found that not only had my pump casing cracked but also the heating unit feed casing. I will have to see if I can either seal it or design and print a new one. I believe it is an injection moulded part made out of polypropylene. I am hoping that I might be able to print something using ABS. When I took the heater apart I saw that the seals for the two end pieces are pretty well shot so I designed some replacements. I printed them in TPU but I don't know if that will hold up to chlorine very well. Most of the seals on this unit look like they have had trouble dealing with the chlorine.
I have added the heater seal for anyone that might need it.
Time to start looking at repairing the heater assembly.

Summary
2025-05-27
My daughter's hot tub began showing the E02 Error so, after following all the troubleshooting directions and not finding a solution, she asked me to look at. I checked online first before disassembling and found the most common issue is a damaged impeller. Before ordering a replacement I asked her to give me the complete pump unit. When she went to disconnect it she realized that most of the water in the spa had drained out. I figured that there must be a leak in the unit somewhere which could also be the problem. After dismantling the unit I found that not only was the impeller unit damaged but also that the outer pump casing was cracked. It must have been a freezing issue that caused the initial damage.
Next step was to order the parts. Impeller and seals, no problem. Easy to find on line and relatively inexpensive (under $30.) Finding a replacement pump casing was not so easy. I couldn't find anything and neither could AI.
My only alternative was to replace the whole pump unit, #P4097 (other number I found on line was 58113) The pump appears to be the same for Coleman, Saluspa, Lay-Z-spa, Bestway etc. and should be widely available as these hot tub units appear to be sold world wide. I couldn't find any matching replacements but for several hundred dollars I could purchase a complete replacement pump heater unit.

Note:
I did locate a post on Reddit that said that there are a bunch of these units that are under recall. You should go to the site and check before bothering trying to repair the pump. https://www.bestwaycorp.ca/recallandsafety
My guess is that the impeller fix solves the overheating problem but if the pump runs with the impeller stuck in place the pump unit would begin to overheat. I expect that it is easier for Bestway to just replace the whole unit rather than having units shipped back and forth to be repaired.

If your unit is not under recall you can continue with the steps that I did to fix your pump.

My next option was to try and design and 3D print my own casing. The only issue I figured I'd have would be how water tight it would be. I assumed that the pressure would be relatively low since its just a recirc pump but I didn't want to have the unit continually dripping water. I thought I would print it in ABS (the original casing appears to be ABS) but my printer that has an enclosure is too small to handle the print so I opted to print in PETG and try and seal it. I figured that if it worked but still leaked I could try and have it resin printed for me since I don't currently have a resin printer.

I printed it in carbon fibre PETG because that was the only PETG I had readily available. I redesigned it slightly to print a little cleaner and make the walls a little thicker, especially where the clamp had to tighten to hold the PVC hoses.

I used a 0.6 nozzle, printed with 100% infill using tree supports at a 45 degree angle. Printing at an angle minimized the support that was required. It is about a 5 hour print on my setup. Keep in mind that you need to make sure all mating surfaces are smooth before assembling the parts. I used a small round diamond file to smooth the O ring slots and block sanded the mating base to ensure that it was also smooth (removed the filament lines.) The inner gasket may be enough but I expect that water would find its way along the filament lines. I suppose a thin layer of liquid gasket on the surfaces would help seal it but I will wait to see how it works without it.

Just to check out the water tightness of the material I printed up a few test connectors that I attached to my garden hose and tested with around 50 psi of pressure. The thinner portions leaked both air and water quite a bit and even the thick portions sweated water that would then continuously drip. I decide to try and seal the units but I didn't have any epoxy resin so I opted to try some home made ABS slurry. I coated the parts liberally and tested again. There was a very small amount of sweating and the parts actually held air at the closed end. I will probably try this method of sealing on the main part if it needs it.

Before I go to the trouble of sealing the whole part I will do a test run just to see how it will hold up without any sealant.

I am still waiting for the new impeller so I have not yet reinstalled the unit. I don't know if this will actually work but crossing my fingers. I am also waiting to find out how much a resin print will cost since that may be the better way to go.

If you do have a resin printer and test it out please comment back with your findings.