The Waterway brand pump on my 4-year old Mountain Springs spa started to screech and howl in the middle of the night. I shut off the power to it and took at look in the morning.
Water is still circulating, although not quite as well as it had previously, and the heater is working, but there is a loud whirring sound that is coming from the pump housing. I’m guessing that the bearings are shot, which isn’t too surprising given it’s age and that it runs every day for at least an hour keeping the temperature up.
I opened up the spa enclosure and was able to see the model number on the pump, so I know the horsepower and voltage etc., but the model number doesn’t tell me the diameter of the intake or output ports, and without taking the tubing off, which will in turn drain the spa, I have no easy way of measuring the dimensions so I can make sure I order the correct replacement parts.
If you can get a tape around the pipe/hose in and out, you can work the diameter (divide by 3.14) - go to hardware store with tape and find pipe with that OD - look at the label on the bin - you now have ID - the common measurement of pipe (at least in USA).
A pipe with an od of 1 1/2" is a 1" pipe (for plastic pipes, wall thickness is roughly 1/4".
You will need a new pump - not just the motor (most likely).
The spa maker will have a part number - you might look around for a spa pump of the same specs.
A good place to ask pool/spa Q’s http://www.troublefreepool.com/index.html
Don’t be surprised if they want you to buy a water testing kit - they do tell you how to stop buying over-priced laundry bleach at the pool store, how to lower Ph (muriatic acid, hardware store), so don’t be surprised that they emphasize water chemistry.
Most spas have a gate valve on either side of the pump, so that you can shut the valves and then remove the pump without draining the spa. Does yours not have those?
There are only a couple of sizes of the piping going through a spa pump, so it should be pretty easy to figure out even without disconnecting the pipes and measuring the inner diameter.
Pumps are easy to replace. Order the pump online, and when you replace it, if you don’t have gate valves now, put a pair in with the new pump so you don’t have this problem again.