Swimming Pool & Spa Construction & Maintenance/Pool / Pump / Waterfall


We just had a natural rock waterfall installed and now that it is finished the water just trickles out of the system and it doesnt really look like a waterfall.
The pool is 14X28 X4.5 with one outlet thru the filter basket and two inlets into the pool.
The line is 1 1/2 from skimmer to a Hayward 0.75hp pump (Super Pump Model C48J) then thru a Hayward Variflow XL Valve - attached to a Pro Series High Rate Sand Filter.
Connected to a Hayward Gas Heater - Model 250FDN
The output of heater goes through a Zodiac Clearwater LM2-15 module and then immediately after that the landscapers put in a TEE and the line can return to the pool or it heads to the waterfall. There is no valve to shut off the return to the pool - only a valve to shut off
The line to the pool is 1 1/2" flex line
The line to the waterfall starts at a simple ball valve and 1 1/2" line then changes to 2" flex line to a manifold with a tee in the middle from the pump and two Tee's on either side equally spaced.
The manifold is 1 1/2" and then immediately off the manifold the lines (4 of them) are necked down to 1 inch. Each of the four lines has a simple ball valve.

SO here are the issues.
1 - the pressure climbs at the vari-flow to about 13 psi and then the heater shuts off - showing LO on the readout. when you direct the line to waste for a minute or to rinse and then back to flow the pressure drops to around 10 and the LO readout disappears and the heater can restart.
2 - when you open the valve on the waterfall side - the heater also reads LO
3 - when the valve is on at the waterfall - the water just trickles out and over the edge. Not even close to a cascading look.

I had a company come in and pressure test the lines and they found no problems.

What is causing my pressure problem and my heater problem?
And why am I not getting good flow at the waterfall?
Is this a pump sizing problem?
Is it a plugged line somewhere (caused by all the recent landscaping work completed and the sand/mortar that fell into pool?

Thanks for the help

Sorry for delay.
A .75hp pump would give a flowrate of 13.8 m3/hr or 58 gpm at 10m or 40 feet head.
A 1 1/2 inch pipe would give a flowrate of 32.5 gpm at 6.6 feet/ sec( a acceptable standard for design) and for a flow of 58 gpm you require a pipe size of 2 1/2 inches which is not the case. hence the issues about LO are present.
The design of waterfall is governed by following formula if thickness is 0.1" the flow rate is 5gpm per foot of the water fall.
If the waterfall is  8 feet long than the flowrate for 0.1" thick waterfall would be 40 gpm(8 X 5= 40gpm) hence you can understand the problem of low flow and top of it the pipe is under sized.

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Manish J.Joshi


Planning, Design, execution, Installation, maintaining, FINA/SPATA/ISPE standards,Trouble shooting in water, Design of filters,U.V, Rain water harvesting, waterparks, themeparks, amusement parks, playground equipments, water slides and spas, Tiling, waterproofing, Feasibility studies


Last fifteen (15)years water industry Especially waterparks, wavepools, swimming pools, spas,

H2O The water Specialist website:- waterparks.in

B.E. major in Construction Engg. M.B.A. Finance

Past/Present Clients
JVPD club India, MCF club India, HFIL in India

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