Pump Replacement

  • Last Post 11 February 2021
SHLPC1 posted this 08 February 2021

I am having problems with my current pump so am looking to replace it.  The pump is a Hayward Single speed (3450 RPM) 3/4 hp Super II Self Priming pump.  The  problem is that the pump’s plastic lid keeps cracking.  The pump is 4 years old and the plastic lid has cracked approx. 6 times.
It appears a Variable Speed pump could solve this issue.  So I am looking for for your advice in this regard.
The Spa is outside (Calgary, Alberta) and has a cover.  It holds approx. 460 gallons, so its Turnover Rate (based on an 8 hour rate) is approx. 1 gallon per minute.
The Average length of Suction Line is approx. 23-24 feet.  The piping is 2”, there are 7 90 degree elbows in the Suction Line and 2 T’s.
The filter is a Hayward Swimclear Model 2030 with a filtration rate of 84 gallons per minute. I am wondering if a Variable Speed Pump could help alleviate this problem

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InyoRob posted this 11 February 2021

I have not come across this issue before. A variable speed pump running on a lower speed would reduce pressure on the pump lid. However, those lids should have no issue with the 3/4HP pump running at full speed. Do you think the lid is cracking due to the cold weather elements in Alberta?


SHLPC1 posted this 11 February 2021

No a temp issue in that the pump, filter, etc are all indoors.  The pump, etc. are located in the basement and pump the water upwards  about 12pm to the Spa.  We have the pump on for 12 hours and then off for 12 hours.  I am thinking that the constant on/off may be stressing the lids over time and at some point they then fail.  I am wondering if a variable pump kept on 24/7 but at a much lower rmp (like 1000 rpm vs the current 3450 rpm) would place less stress on the entire plumbing system.

InyoRob posted this 11 February 2021

Since the weather is not an issue, my guess would be that excessive back pressure could cause the lid to crack. A variable speed pump would decrease that back pressure.