Hotsprings Classic - Heater problem

[boulaa]

Heater on 91 Hotsprings Classic burned out. Measured open with meter.  I did notice that one of the posts of the plug had turned a copper color and had some rubber or plastic around the base of it,  Possibly from the receptacle on the control panel.  Seems like that post may have been over heated.The circulation pump was working fine. 

The tub has been working fine all summer and up to a week ago was at 104 deg..

I was lucky enough to find a local Hotsprings dealer who had one in stock yesterday (#31255) and replaced it. There are no leaks after replacement so I turned back on yesterday but the heater would not heat up. I checked for any heat after a few hrs and its like heater never turns on.  I have a concern that I may have damaged the heater because I measured the resistance at 80 ohms before I installed and now its at 8 ohms. (that to me is almost a short ckt)

I am now suspecting something in the control box, probably a stuck relay, etc.  That may be why one of the plug posts overheated and discolored.

So my questions are

1. What is the resistance on a new heater supposed to be ?

2. What could cause the heater to burn out and the new one not to turn on ?

3. Anyone have a schematic of the control box ?

I had to drain the tub today  because I'm in NH and the temp is in the 20's now. I plan to pull the heater and pump today and see it the heater will work with 115 VAC directly applied to the plug posts.

Thank you for any help. I'm desperate to get this fixed for the winter.

Al

[Gallip]

Schematic is normally glued to inside of control panel cover

[boulaa]

Thanks for the location of the schematic. I now remember I saw it 10 years ago when I had to replace an MOV that burned in the panel.

I have now deduced that the circulation pump seems to be the issue after bench testing the heater and the pump with water. I applied power to the new heater in the housing and the water heats up fine. I applied water and power to the circ pump and it runs....but the weird part is that the pump is pumping in reverse,  so the water would not be pumping into the heater housing.

The intake and output on the pump are now reversed when the pump is running, so it is like the pump is trying to pump in the opposite direction. Its like I reversed the output and input hoses...but I didn't. I took pictures before I pulled the pump and heater...also the shape and length of the tubing wouldn't allow it. This was working fine all summer and up to a week ago.

I have never heard of an AC motor suddenly running in the opposite direction. Has anyone heard of this before ?

Seems like I could fix my problem by reconfiguring the tubing to allow for the motors reverse in direction, but I am afraid it will reverse direction again and I'll burn out the new heater.

I know this sounds crazy.  I have been in electronics most of my life and this really has me baffled. I have successfully rebuilt the jet pump, replaced the circ pump twice and the heater element once, and replaced the MOV in the past 10 - 12 years ....but I am totally confused with this one.

Any input would be appreciated.

Thanks

Al

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

[Jersey Hot Tub Repair]

Is your circ pump a Laing pump or a Grundfos pump?  The Laing pumps use magnets instead of a shaft to turn the impeller.  While I'm not sure what that could have to do with the pump running in reverse, maybe it's a clue for you?

[boulaa]

Its a Watkins E5 that I installed a few years ago.

[Jersey Hot Tub Repair]

The E5 is made by Laing and has a magnetic coupling.  As I said, I don't know if that is even significant.  I'm just thinking out loud: 

I'd try running the pump directly from your house outlet  (use an old extension cord and a couple of alligator clips).  See if the problem is really the pump or is it the power coming from the circuit board.  If doing that makes the pump run in the correct direction,  it tells you the pump is fine and either the circuit board or wiring harness is the problem.

If you reverse the hot and neutral wire, maybe the pump would operate in the opposite direction?  I realize that for A/C power that shouldn't matter, but since the coupling is magnetic, perhaps there's more going on in the pump's electronics than we would expect.

If reversing the neutral & hot makes a difference, I'd sure like to hear about it.  I would try that if I were working on the tub.

I don't think you'd burn out the heater if you reversed the plumbing and the pump unexpectedly reversed direction.  If it did, the flow switch would open and shut the heater off.  I don't remember if the impellar is curved or not, so running the pump in reverse may not move enough water to close the flow switch, but the only way you'll know is to try it.

[boulaa]

Its a Watkins E5 that I installed a few years ago.

[boulaa]

I already reversed the input power knowing that it was AC and wouldn't make a difference...but I was desperate. Did not make a difference.  I'm going to try and get in contact with an Application Engineer at Lang or Watkins to try and make sense of this. I m also going to dissect the previous circ pump I had replaced to see if I can figure it out. Its an E5 also. This is the Watkins universal replacement for the older Hotsprings spas but they only seem to last a few years because of their almost 100% duty cycle.

My concern is  if I put in in pumping in the reverse direction and it changes direction again I burn out the heater...because the original did burn out for some reason last week. Don't want to risk another $150. on a new heater just yet.

 

 

[Jersey Hot Tub Repair]

I just googled "A/C motor running in reverse" and got 2.2 million hits.  It seems you're not the first person to have this issue.  Unfortunately, many of the results are in areas I'm not familiar with.

If you find anything out, I hope you'll consider sharing it here, I'd love to know what happened.

[PreservedSwine]

The motor isn't running in reverse.

 

You have a broken check valve the is there to prevent water running backwards through the circ pump when the jet pump is energized.  

That spa uses a single filter, thus the jet pump will overpower the circ pump in the battle for water, and since the intake of both pumps are both ultimately tied to the filter, when the check valve is broken the jet pump sucks the water backwards through the circ pump.

 

Additionally, ~8 ohms is normal, 80 is not. 

The E-5 circ pump is not a good choice for that spa, as the self priming feature has a nasty little tendency to engage after running the jet pump, and the heater will subsequently overheat and trip the high limit.  Next time it fails (and it will) use 120v E10 circ pump.  It moves enough water to not go into a priming cycle when the jet pump us running.

 

 

[boulaa]

To be clear, I had removed the circ pump from the hot tub, primed the pump and applied AC to the plug, I applied water source to the input port ( bottom) of the pump and with the pump running very little water came out of the output port (top). I then applied the water source to the output of the pump and the water pumped perfectly out of the input port . Very weird  I am assuming the check valve you are referring to is associated with the hot tub components and not in the circ pump ?

I agree with you about the robustness of the E5 and have replaced them twice. one just stopped running altogether a few years ago and caused a freeze up while I was out of town  I will definitely look into the E10

[PreservedSwine]

There were 2 possible check valves used during that era, both on the pressure side of the circ pump in netween the circ pump and the heater.  One is clear plastic, and very clearly a check valve, the other is white pvc, and looks almost identical to a 1/2" pvc coupling.

I never say never, but in the 30+ years we've been repairing Hot Springs Spas (over 30,000 of them) I have never seen, or heard, of the cir pump suddenly reversing direction.

 

However, the check valve failing, and the jet pump sucking water backwards through the circ pump was a very common issue with that spa back in the 1990's. 

 

You will continue to replace the E-5 on a regular basis with that particular spa. Next time it gives up the ghost, buy the E-10, and you problems are over.