Pump will only operate at low speed not high speed

[JWL]

Have an Arctic Spa hot tub. Replaced the motor 5 years ago with a Massage Master XLT PF-45-2N22C.

Tub was shut down and winterized for the winter. Flushed, filled and fired it up. At first use high speed didn't work. I think I tried it when the tub was filling and high speed worked but now it doesn't. 

When I switch from low speed to high speed it just goes back to circulation speed (because it is currently heating the tub up from a fill).

Any suggestions are appreciated.

[RDspaguy]

So, it goes on to high speed but immediately turns back to low? How cold is the water?

[JWL]

23 minutes ago, RDspaguy said:

So, it goes on to high speed but immediately turns back to low? How cold is the water?

Because I just filled the tub it is circulating water and heating it.

When I press the low speed button it sounds like it is working but there really isn't much of an increase in circulation.

When I press the button again to go to high speed it just drops back to circulation (below low speed). It does not go to high speed.

Just through circulation it does heat the spa up.

I did remove the pump and checked that the impeller moved freely (I thought maybe it was broken but it seems ok).

[RDspaguy]

I am not sure what you have there, but if your control is set up for a low amp mode, or 120v, the heater can't run if the pump is on high. If the water is cold, the heater may override the high speed pump and turn it off. So I ask again, how cold is it?

The pump running but not moving water could be an air lock, closed or stuck valve, or any number of things. Did you fill through the filter pipe? Are all of your valves open?

[CanadianSpaTech]

 

9 hours ago, JWL said:

Because I just filled the tub it is circulating water and heating it.

When I press the low speed button it sounds like it is working but there really isn't much of an increase in circulation.

When I press the button again to go to high speed it just drops back to circulation (below low speed). It does not go to high speed.

Just through circulation it does heat the spa up.

I did remove the pump and checked that the impeller moved freely (I thought maybe it was broken but it seems ok).

There is no "Below low speed". It's a 2 speed pump hi and low. If it is heating without an error code it is running in low speed.

Observe the pump shaft when you press it into high speed does it speed up?

Also remove the filter until you get this figured out.

 

[JWL]

Sorry about that. I guess I skipped chapter 1 of the story which would have been helpful.

The tub had been winterized and not used over the winter. Tub is in Kingston Ontario, we were in Florida for the winter.

I had previously filled the tub, switched on the breaker and left it for hours. It heated up to 103*

On our first use the low speed barely worked. When we switched to high speed there was a click and then nothing.

I tried multiple techniques to resolve possible air lock, but no change. So I thought it might be a stuck impeller. I drained the tub (oddly only a shutoff valve on the pipe going into the pump). Removed the motor. The impeller moved freely.

Reinstalled the motor. Filled through the filter pipe. Switched the breaker on. Initial tub temp was 66* and it started heating in circulation mode. Perhaps being a bit impatient I tried the low speed which moved a little more water but sounds busy. When I switched to high speed it just went back to circulation.

Now that I think of it more, doesn't seem like even low speed there is not much flow but there is some.

[CanadianSpaTech]

Is there a separate pump for circulation or does the spa run the main 2 speed pump on low for heating and filtering?

Did you remove filters?

Were any of the gate valves used when winterizing the spa. Make sure all of the valves are completely open and in line with the plumbing.

[JWL]

18 minutes ago, CanadianSpaTech said:

 

There is no "Below low speed". It's a 2 speed pump hi and low. If it is heating without an error code it is running in low speed.

Observe the pump shaft when you press it into high speed does it speed up?

Also remove the filter until you get this figured out.

 

Thanks. Was typing up a response when your comment came in.

I've removed the filter. It is heating without an error code.

So given the info on "it only has 2 speeds", low speed seems weak and high speed makes noise but water movement only increases a tiny bit.

Temp is 69*. Manual does seem to indicate that high speed will work even if temp is low

[JWL]

18 minutes ago, CanadianSpaTech said:

Is there a separate pump for circulation or does the spa run the main 2 speed pump on low for heating and filtering?

Did you remove filters?

Were any of the gate valves used when winterizing the spa. Make sure all of the valves are completely open and in line with the plumbing.

Only 1 pump, so I guess it uses low for heating and filtering.

Did remove the filters.

No gate valves used. Both intake and output pipes were disconnected from the pump when I winterized it.

[CanadianSpaTech]

Are all the jets open? turn face of jet counterclockwise to open. To me it sounds like a blockage somewhere in the system. It seems to be working as it should just not enough pressure leading to a flow issue. What about the suction returns in the foot well are the open and sucking water. Make sure they are not covered in hair or some other type of debris. Filter are out, water level is well above filter basket,  Blue handle Ball valves are open and in line with the plumbing, There is nothing that has gotten past the filters and into the face of the pump (this would be my go to but you said you checked). The only other thing I can think of is there is a spring loaded flapper at the bottom of the filter canister that might be sticking. This flapper is usually what I find missing and has gone down and into the face of the pump/impeller when this type of low flow issue occurs but I have also found kids toys, g strings and so on. You would have to reach all the way down to the bottom of the canister. Again visually inspect the pump shaft if possible and verify the 2 speeds. If you have that then your problem is likely a blockage of flow somewhere in the system but hard to say for sure from here.

[CanadianSpaTech]

Arctic might have used a one way check valve in line on the suction side that might be gummed up and sticking closed. See attached:

https://arctichottubparts.com/plumbing/ball-check-valve/check/check-valve-2-1-2lb-spring.html 

Put your hand over the suctions in the foot well and see if there is any suction. Then try at the bottom of the filter canister and see if it is greater there. Not sure if this will tell you anything but worth a try

[RDspaguy]

So, with the filter out it is heating, but the pressure seems low. High pump makes noise but no significant increase in flow? You have put your hand over a jet to check, or is it a visual assessment? Are your air control knobs open? Does the pump turn off when it reaches temperature? Check by turning set temp down below actual temp. Does the pump have a plug connection to the board or did you have to wire it up?

It sounds like a spun impeller to me. I wouldn't think a bad spring valve would starve the pump with the filter out, even on high. Unless it is built in to the filter and blocking both suction and filter, as Canadaguy said. Spun impeller would have near normal low speed, but high speed slips making a grinding noise and flow stays pretty constant. It would act very similar to a suction blockage. 

[JWL]

Thanks very much for all your ideas @CanadianSpaTech.

I checked the flapper at the bottom of the filter canister and it is there and the spring is holding it closed, but it can be opened.

I turned the hot tub temp down below the current temp so I don't have the confusing situation of having it run low speed continuously while it tries to heat the pump.

You are correct that there is a check valve after the pump (never knew that's what it was).

When the spa has been sitting for a bit, and I turn on low speed, there is a "clunk". No weird sounds when I switch to high speed. If I turn the pump off, then go to low speed again. There is no "clunk". Then if I leave it for a bit and try low speed it will "clunk" at the start.

When I let it run for a bit at high speed, the flow did seem to pick up a bit. Got a "swirl tornado" into the filter canister, but still not the regular flow.

[JWL]

33 minutes ago, RDspaguy said:

So, with the filter out it is heating, but the pressure seems low. High pump makes noise but no significant increase in flow? You have put your hand over a jet to check, or is it a visual assessment? Are your air control knobs open? Does the pump turn off when it reaches temperature? Check by turning set temp down below actual temp. Does the pump have a plug connection to the board or did you have to wire it up?

It sounds like a spun impeller to me. I wouldn't think a bad spring valve would starve the pump with the filter out, even on high. Unless it is built in to the filter and blocking both suction and filter, as Canadaguy said. Spun impeller would have near normal low speed, but high speed slips making a grinding noise and flow stays pretty constant. It would act very similar to a suction blockage. 

Thanks @RDspaguy

LOL, I just did what you suggested (turning the temp down) and that does stop the pump.

If spun impeller means it is slipping on the shaft that seems like a pretty possible explanation. When I took the pump out previously I checked that the impeller spun because I was worried it was broken or stuck. Maybe it was moving too freely. It didn't take much force to move it along. Should it take some force to move the impeller and motor manually?

 

[RDspaguy]

Not much force if the bearings are good. There should be no wobble or side to side movement.

Did you check the air controls? What about wiring?

[CanadianSpaTech]

Well if you remove the pump again there is a slot at the back of the pump behind the dust cover and you can hold the motor shaft with a flat head screw driver and try to spin the impeller by hand. The impeller is screwed onto the shaft and you should not be able to spin the impeller if you are holding the other end with the screwdriver.  I have seen the impeller shear off but never spin on the shaft but sounds like RD has. 

Is the one way check valve serviceable or all one piece? 

[JWL]

4 minutes ago, RDspaguy said:

Not much force if the bearings are good. There should be no wobble or side to side movement.

Did you check the air controls? What about wiring?

Air intake is open.

I also opened the diverter control so the water from the pump was flowing out there. It was still slow with the pump at high speed.

I haven't checked the wiring but there have been no changes.

Going to remove the pump and hope(?) that it is a spun impeller. Unfortunately it looks like the check valve isn't checking to I have to drain the tub again!

[RDspaguy]

Check valve isn't checking? Which check valve is that? I thought you had gate valves.

[JWL]

1 minute ago, CanadianSpaTech said:

Well if you remove the pump again there is a slot at the back of the pump behind the dust cover and you can hold the motor shaft with a flat head screw driver and try to spin the impeller by hand. The impeller is screwed onto the shaft and you should not be able to spin the impeller if you are holding the other end with the screwdriver.  I have seen the impeller shear off but never spin on the shaft but sounds like RD has. 

Is the one way check valve serviceable or all one piece? 

Thanks I'll test the impeller that way.

Check valve seems to be one piece but I'm not sure. It is different (older?) than the one you sent a link to.

[JWL]

3 minutes ago, RDspaguy said:

Check valve isn't checking? Which check valve is that? I thought you had gate valves.

There is a ball valve for the pump intake line.

It looks like a check valve for the outflow line. https://drive.google.com/open?id=1Qoe4Nwt332NbS46Bvd971Ko6KLqkHGPH

When I loosened the connection from the output line the water was flowing out longer than it should have been with the ball valve closed if the check valve was working.

[RDspaguy]

6 minutes ago, CanadianSpaTech said:

Well if you remove the pump again there is a slot at the back of the pump behind the dust cover and you can hold the motor shaft with a flat head screw driver and try to spin the impeller by hand. The impeller is screwed onto the shaft and you should not be able to spin the impeller if you are holding the other end with the screwdriver.  I have seen the impeller shear off but never spin on the shaft but sounds like RD has. 

Is the one way check valve serviceable or all one piece? 

I have seen the threaded tip of the shaft shear off once, but usually the impeller cracks at the base of the shaft. That is what I meant by spun impeller. It is usually a jagged break, so still moves the impeller some from the edges catching.

What check valve is everyone talking about? Are we talking a spring valve in the filter canister, a spring valve in the pvc for filter bypass, or a pressure side check valve?

[CanadianSpaTech]

I think there is a large 2" or 2.5 check valve. I think on the suction side between the foot well suction drains and the pump. https://arctichottubparts.com/plumbing/ball-check-valve/check/check-valve-2-1-2lb-spring.html

Yeah usually the factory check valves are one piece. It could be gummed up but at this point we are way down the rabbit hole and are only looking at the check valve if all other avenues have been explored and eliminated.

 

 

[CanadianSpaTech]

It could have anywhere from a 1/2 lb spring up to 2 or 3 lb spring. When running in low it might not open and only suck through one floor suction and filter then when you go into high speed the suction is greater and the spring loaded flapper opens to suck through a second/third floor suction (but I'm not an engineer...oh wait...lol Rd inside joke)

[RDspaguy]

Ok. Outflow meaning pressure side of the pump? Pressure side check valve not closing? I think that might be the entire problem. I misunderstood, thought you were talking about the spring valve for filtering. Check valves have a flap on a rubber sheet hinge. I call them flappers. The rubber is notorious for getting brittle with time, ph, and chemicals. Eventually it breaks. The flap floats free but will not fit in the pipe, so when pressure hits it the flap closes off the outflow, or most of it if it goes a little crooked. Cut it out and couple it if you can't get a valve. It's only purpose is to let you pull the pump without draining.

[JWL]

2 minutes ago, RDspaguy said:

Ok. Outflow meaning pressure side of the pump? Pressure side check valve not closing? I think that might be the entire problem. I misunderstood, thought you were talking about the spring valve for filtering. Check valves have a flap on a rubber sheet hinge. I call them flappers. The rubber is notorious for getting brittle with time, ph, and chemicals. Eventually it breaks. The flap floats free but will not fit in the pipe, so when pressure hits it the flap closes off the outflow, or most of it if it goes a little crooked. Cut it out and couple it if you can't get a valve. It's only purpose is to let you pull the pump without draining.

OK. I can remove the heating tube and should be able to look down the pipe at the check valve to see what is going on. I'll do that before I remove the pump as it is a PITA to remove.

That sounds pretty plausible. But I think I liked the impeller replacement possibility better 😁. Replacing the check valve is going to be a challenge because of how the tub sits in my deck.

Man you guys are good at identifying potential problems, even with my haphazard descriptions.

Thanks so much @RDspaguy and @CanadianSpaTech