Hot tub pump odd behavior

dunginhawk

Bronze Supporter
Jul 11, 2018
189
0
CLIVE/IA
#1
So ive had my tub only about 3 months but this is the second time its happened. What occurs is the main pump 2 speed slows down for about 1 second then back to normal, and repeats.
I dont recall what caused it last time, it may have been low water, however I dont think im anywhere close to the water level it was at when that happened.
Anything else that could be causing this? filters were cleaned a week ago. No debris in the basket. Tub is 100% balanced chemically as of today...
any ideas?
thanks
 

ajw22

TFP Guide
Gold Supporter
Jul 21, 2013
2,684
0
Northern NJ
#2
When you say the pump slows down, does it do it on hi or low speed? Is it going from hi to low or to off and on?

My WAG is you have a flaky relay.
 

dunginhawk

Bronze Supporter
Jul 11, 2018
189
0
CLIVE/IA
#3
I dont think it goes from high to low (not all the way) as in the 2 different speeds of the pump.
Its like if High is 100, and low is 20 it drops to maybe like 70. Its just a little drop in pressure then it comes back up. Definitely not instant like flipping a switch would be (or what I imagine a relay hiccup would be).
To me it feels like its just laboring to pull water/air in like its sucking up a diaper. But of course there is nothing blocking anything, and the filters arent dirty. Ill clean them today, but I do that weekly as a matter of habit.
 

ajw22

TFP Guide
Gold Supporter
Jul 21, 2013
2,684
0
Northern NJ
#6
Can you open up the sides of the hot tub and examine the piping. Especially the suction lines between the drains and the pump?

PVC glue joints in hot tubs often lossen.
 

dunginhawk

Bronze Supporter
Jul 11, 2018
189
0
CLIVE/IA
#7
Hope thats not the case after 3 months :) I dont have that option at the moment unfortunately. we have 7 inches of snow today and more falling :) but it did happen a month or so ago too, then didnt happen until last night.
thanks
 

BMK

Bronze Supporter
Mar 30, 2016
197
0
Pittsburgh, PA
#9
Here's whats possibly happening.....When using the tub, someone may have inadvertently brushed against the water intake, momentarily interrupting waterflow through the pump. It may even cavitate a few times before normal flow resumes. The intake (suction) is usually located on a vertical surface, about ankle high. In my tub, it's located right behind the shins if someone is sitting on the interior entry/exit step, which also doubles as a secondary seat. Rarely does anyone sit there, but when they do, their leg sometimes brushes the intake, causing the exact result you're getting.

Of course if it happens when you run the tub with no one in it, this obviously isn't the problem, but I thought it might be worth mentioning.
 

dunginhawk

Bronze Supporter
Jul 11, 2018
189
0
CLIVE/IA
#10
BMK, i absolutely thought about that and figured that is certainly possible. In fact thats exactly what the change in flow would be if i did that.. However, i was the only one in the tub, in the lounger, no where near either intake.
So I wish it was that easy :(
thanks
 

dunginhawk

Bronze Supporter
Jul 11, 2018
189
0
CLIVE/IA
#12
So i added about 40 gallons of water last night, and got in tonight... issue seems resolved... its so odd that that occurs because all of the jets are under water in this "low" water time. It doesnt appear to be starved for water..
very strange.