Old inground spa and pump

[greeensky]

hello there,
where we have recently moved in there is an old inground spa approx 3000L, the previous owner removed the pump. I got a second hand 1.5hp Paramount pump. It does nothave a skimmer so it makes priming more difficult. Additionally the whole pump, heater, and cartridge filter are located 3m away from the pool approx 40-50cm above water level. To make priming easier I installed a not return valve before the pump which I fill with water. The water flow is very weak, hardly any flow coming out of the jets. The pump is working, I have checked the impeller no debris etc. I am aware of other potential issues iec onnections may not be 100% tight, in fact i did not want to glue the return valve so i used silicone and builders tape but I wonder if that would so significantly impact the water flow. The tall cartridge filter hardly fills with water of course. I have attached 2 pictures of the setup, you will see that pump needs to push the water up from the outlet approx 2ft up and then down to the heater.
I would be grateful if you could confirm or suggest any other potential cause of the weak flow and any tips. Assuming the pump works as it should , I wonder if it is suitable to be installed above the water level (some pumps Daveys need to be installed on the same or under water level). If not what pump I should be looking to buy, are there any special pumps with suction which are more suitable for above water level. Many thahnks Paul

 

[DavidLast]

Do you bleed the air out of the cartridge on start-up?

 

[greeensky]

Do you bleed the air out of the cartridge on start-up?

we've tried both with the cartridge lid open and closed but as there is hardly any water at its bottom i guess i doesnt matter. i did pull out the pump and tested it. i primed it from the top (poured water into a connected pipe) and inlet pump was submerged in a plastic fish container. once i got suction, it kicked off and emptied the 60L bucket in 2-3 seconds. So the pump seems to have a lot of power. So i think it comes down to priming. I am going to try to install the valve (attached photo) on top where the pipes form reversed letter U. That way I will be able to pour water from the top (as during my test rather then before the pupmp where that valve is currently installed.

 

[DavidLast]

I see you are in Auckland, and the filter is labelled FPI. FPI hasn't traded since about 1999. I may be out a few years and haven't been in NZ for many years so that it may have traded longer there.

From memory, these filters had a small knob you unscrewed on the lid on the opposite side of the pressure gauge. Is this still there?

 

[greeensky]

I see you are in Auckland, and the filter is labelled FPI. FPI hasn't traded since about 1999. I may be out a few years and haven't been in NZ for many years so that it may have traded longer there.

From memory, these filters had a small knob you unscrewed on the lid on the opposite side of the pressure gauge. Is this still there?

no the only knob is on top of the lid which you unscrew first and then lift the lid, however where you suggested there may be one, there is a bulge similar to where the pressure gauge is installed. So this seems like an optional thing where a small knob could be installed (see pic). The o-ring seal is in good condition and still lubricated. But the filter is behind the pump and the heater so i guess it should not affect priming even if the lid was open (?)

what i have discovered which I did not notice before, where the pipe enters the wall at the bottom of the wooden board, there is a black valve check (pic 2, likely a spring one). i dont have a wrench right now but going to check if it still works or/and the seals mayb be old and need to be replaced. i did notice earlier but did not realise it was a a valve...

 

[DavidLast]

no the only knob is on top of the lid which you unscrew first and then lift the lid, however where you suggested there may be one, there is a bulge similar to where the pressure gauge is installed. So this seems like an optional thing where a small knob could be installed (see pic). The o-ring seal is in good condition and still lubricated. But the filter is behind the pump and the heater so i guess it should not affect priming even if the lid was open (?)

Okay, we can use the gauge. It's not a great idea, but for now.

Unscrew the filter gauge so it is not loose but nearly loose.
Prime pump and get it running.
Wait (could be 8 minutes) until a continuous stream comes from the gauge, and then tighten it (by hand) until the water just stops.

Did this work as expected?

 

[greeensky]

Okay, we can use the gauge. It's not a great idea, but for now.

Unscrew the filter gauge so it is not loose but nearly loose.
Prime pump and get it running.
Wait (could be 8 minutes) until a continuous stream comes from the gauge, and then tighten it (by hand) until the water just stops.

Did this work as expected?

thanks will let update once i get a chance to check the non return valve

 

[greeensky]

@DavidLast
i owe you some update. after other unsuccesful attempts i have used some pump and connectected to inlet in the pool . i was expecting to see the water in the system or in the pump but instead there was big resistance. then i tested shorter pipe section , unscrewed the pipe from the pump and then after another non return valve where the pipes enter the ground on the other side of the wall. still no flow both ways. so i thought the spring in the valve was blocked or sth else was blocking. what we have found was smal piece of rug trapped in the valve. Perhaps for a maintenance guy it would have been more obvious to check this valve earlier but still would take some time to figure out everything to I have saved some $$$.

We did test 1.5hp pump and I managed to prime it straightaway but for 4 jests and 2600L and 40mm i think it is too powerful. i have got another second hand 1.25hp but it may be still too powerful. im told that between .35hp - .75hp would suffice, even .35hp for lower power bills as there apparently difference in water pressure between the two is not significant. on the other side I have read that .25hp per jet is rule of thumb but it may be more applicable to modern spas. I am going to post a new post here for 2nd opinions.

Thanks for your time and earlier suggestions.

 

[greeensky]

Hi,

I have this old type inground spa as per photo attached. It is 2600L and has 4 jets. Pipes in the system are 40mm. Would be grateful for some opinions and pros and cons of having less or more powerful pump. The pump would sit approx 40-50cm above water level, 3m away from the spa. I am told that either .75hp or even as low as .35hp would suffice or sth in between ie .5hp. Would you agree? Apparently there is not much difference in water pressure those pumps would generate. But for power consumption .35hp would be less costly. Given the spa is quite old as are the fittings I dont want any rapture but also have some decent flow from the jets.

thanks

 

[1poolman1]

Hi,

I have this old type inground spa as per photo attached. It is 2600L and has 4 jets. Pipes in the system are 40mm. Would be grateful for some opinions and pros and cons of having less or more powerful pump. The pump would sit approx 40-50cm above water level, 3m away from the spa. I am told that either .75hp or even as low as .35hp would suffice or sth in between ie .5hp. Would you agree? Apparently there is not much difference in water pressure those pumps would generate. But for power consumption .35hp would be less costly. Given the spa is quite old as are the fittings I dont want any rapture but also have some decent flow from the jets.

thanks

Get a variable-speed pump and you can adjust the flow to meet your needs.

 

[greeensky]

Get a variable-speed pump and you can adjust the flow to meet your needs.

i guess that would be ideal but variable speed pump are a couple of times more expensive. Tevoli or Whirlpool pumps single speed are v. affordable.

 

[mas985]

You need to match the pump with the flow rate requirements of the jets and the head loss in the plumbing. Also, you really can't size a pump by only the HP rating. You really need to know what the head curve looks like.

Do you know the nozzle size of the jets and/or the flow rate requirements?

Can you post a picture of the head curve for each pump you are looking at (or a link to the site)?

40 mm is pretty small pipe for a spa. Is there only a single pipe going to the pump?

 

[DavidLast]

Whilst I recall...with the FPI filter. Could you take the cartridge out? While it's out, using a torch, look where the rod threads into the brass knurl in the bottom of the tank. If there are cracks in the plastic around the brass knurl, it is likely the filter should be replaced. These filters had a common fault the rod would pull out of the base over time.

 

[greeensky]

th

You need to match the pump with the flow rate requirements of the jets and the head loss in the plumbing. Also, you really can't size a pump by only the HP rating. You really need to know what the head curve looks like.

Do you know the nozzle size of the jets and/or the flow rate requirements?

Can you post a picture of the head curve for each pump you are looking at (or a link to the site)?

40 mm is pretty small pipe for a spa. Is there only a single pipe going to the pump?

thanks for getting back. there is def. more technical info that i did not consider. yes pipes are 40mm and one single pipe going to the pump. it will bend at 90degree 2-3 times what i can see. The pump will then push the water up approx 60cm high and then into the heater. i have unscrewed the jet (maybe you will recognise what it is) but when i stuck my finger deep inside there is a narrower part approx 10mm in diameter.

 

[mas985]

That is the exterior fitting, not the nozzle. The nozzle is deep within the spa wall.

 

[greeensky]

That is the exterior fitting, not the nozzle. The nozzle is deep within the spa wall.

View attachment 549005

thanks for sharing. so yes that nozzle is about 10mm at the front and get narrower inside i think. really hard to measure now.

i also got this 1.25hp Badu pump which i bought cheap with a spare filter. aside what you may recommend based on so far info, do you think i would risk anything (pipe rapture) testing this pump ?
.https://myonlinepoolshop.com.au/products/speck-badu-super-90-series-90-350-1-25hp-pool-pump

 

[greeensky]

Whilst I recall...with the FPI filter. Could you take the cartridge out? While it's out, using a torch, look where the rod threads into the brass knurl in the bottom of the tank. If there are cracks in the plastic around the brass knurl, it is likely the filter should be replaced. These filters had a common fault the rod would pull out of the base over time.

thanks for bringing this into my attention. i think its fine. i have actually two of those but slightly different models. i purchased a 2nd one in better condtion and pressure gauge working however my original FPI has a plastic pipe and a button with a spring at the bottom. see the top filter on the photo. do you know what are thse for?

 

[mas985]

What pump do you have now that was in the picture? Was that sufficient for the spa jets?

Bursting pressure for pipe is well over what a pool pump can produce. There is zero risk of the pipe bursting or pretty much anything else as most equipment is rated well over 50 PSI.

 

[greeensky]

What pump do you have now that was in the picture? Was that sufficient for the spa jets?

Bursting pressure for pipe is well over what a pool pump can produce. There is zero risk of the pipe bursting or pretty much anything else as most equipment is rated well over 50 PSI.

i meant not bursting the pipe but rapture one of the older fittings under the pool. they will be likely oover 15 years old.

the pump is 1.5hp Paramount but ive sold it as I thought it was too strong. Now I have this Spec Badu 90/350 series self priming 1.25hp. i havent connected it yet but thought it has different thread fittings i would cosnider giving it a go in this case. So i guess if there is no risk, the only consideration is what flow pressure from the jets i want to achieve and/or consider lower hp for less power consumption. What about the FPI cartridge filter, will it not provide too much resistance for 1.25 or 1.5hp power pump which over time may impact the motor?

 

[mas985]

i meant not bursting the pipe but rapture one of the older fittings under the pool. they will be likely oover 15 years

Fittings are usually rated just as high as pipe.

the pump is 1.5hp Paramount but ive sold it as I thought it was too strong. Now I have this Spec Badu 90/350 series self priming 1.25hp. i havent connected it yet but thought it has different thread fittings i would cosnider giving it a go in this case. So i guess if there is no risk, the only consideration is what flow pressure from the jets i want to achieve and/or consider lower hp for less power consumption.

How much do you really use the spa where power usage is even a consideration?

How long do you run the pump each day? Shouldn't need more than 30 min for just circulation and filtering.

What about the FPI cartridge filter, will it not provide too much resistance for 1.25 or 1.5hp power pump which over time may impact the motor?

It should be fine. Those are med head med flow pumps.