Seaflo pump problem

[MHS]

I have just replaced a Seaflo pump with the identical model. SFDP1-033-035-41. It’s filled the calorifier, supplies the taps, but won’t turn off, continuing to pressurise the system until water leaks from the INLET side. 

 

Any ideas please. Is the built in pressure switch faulty? It is implied that this is factory set, but is in then adjustable?

[smileypete]

Looks like the little allen key screw in the middle of the black box bit is the pressure switch adjustment, try winding it out some?

Failing that a decent 'square D' pressure switch can be had for about £20 on Ebay or Farnell, there's some cheap knockoffs from about £12 too.

That model seaflo looks like a knockoff of a flojet design to me.

Edited December 30, 2017 by smileypete

[MHS]

Hi Smileypete Many thanks for posting.  

I had just investigated the Allen screw, which sorted it and then read your post. Pressure is reduced and it’s working fine. 

Why on earth does it not mention the adjustment in the installation manual?

[MHS]

I’ve just woken to the sound of the pump running for 10 seconds. Great. That means that excess pressure has probably caused a joint to start leaking on the system. Let’s hope that’s easy to find in the morning. 

[MHS]

So this morning I switched on the pump and it continued over-running again. It seems to be massively pressurising the calorifier but not the cold system. When I switch the pump off, the hot water runs for ages, the cold for a normal length of time.   Help Please!!!

[PaulJ]

Guessing here without seeing it. 

Does your calorifier have a one way valve? This and alot of air in the calorifier will make it act like a massive accumulator tank- this would explain why you are getting what seems to be 'more pressure' in the hot water side and the pump will take forever to pressurise the system.

Are you sure you dont have an air leak on the inlet side of the pump as you said you had a leak on the inlet side?

Edited December 31, 2017 by PaulJ

[smileypete]

If there's an accumulator or expansion vessel, there should be a standard car type valve under the cap on top.

Putting a tyre gauge on it should help tell how much pressure the pump is pumping to. With an expansion vessel it's best to first open the hot tap and release pressure with the pump off, especially after any adjustment of the pump.

Generally the expansion vessel (usually after the calorifier hot outlet) is set to the cut out pressure of the pump, generally around 2 bar/28 psi and any accumulator (usually found next to the pump) is set to the pump cut in pressure which is generally about half the cut out pressure, ie 1 bar/14 psi.

Easiest way to avoid heartache and hassle with pressure problems is fit a water pressure gauge, usually about £10ish.

Edited December 31, 2017 by smileypete

[MHS]

Thanks Paul & Pete. Think we’ve solved it. It’s wasnt the calorifier as I had filled this yesterday while opening the top valve. It wasn’t the accumulator as this is 3 months old  

I reckon it was an airlock in the hot water pipes on the route between the rear mounted accumulator and the bathroom basin around 30’ away. Now cleared, we seem to be sorted. 

Will look for a pressure gauge as this sounds useful. Any recommendations of a good one from anyone would be appreciated. 

Cheers Mike

[Glynn]

I bought a new Sealflo pump a couple of years back, it did the same thing. Got a refund, they didnt ask for it back so I binned it.

Too risky for a boat imo. Then fitted a Jabsco Parmax 4, this has been perfect.

[smileypete]

Anything that will read to the range you need and handles water, eg:

http://www.ebay.co.uk/itm/Practical-Pool-Spa-Filter-Water-Pressure-Gauge-Mini-0-60-PSI-0-4-Bar-TS-50-SW/132427717105

They usually have a 1/4" BSP tapered connection so need a hex bush to get to the more common 1/2 BSP size, eg:

https://www.screwfix.com/p/bush-x-2-pack/79207

Once fitted it's really easy to find the cut in/cut out pressure on the pump, simply run the tap very slowly and see where the needle ranges between.