Calorifier and water system question

[neil1967]

I have an old (belt driven) and noisy jabsco fresh water pump, but it still does its job. I guess it is the same age as the boat - 25 years old. It is connected to a 1 litre plastic accumulator, which definitely is not working - the moment you turn a tap on or off, the pump starts and stops, respectively. I have tried recharging the accumulator, with no success, but it's not exactly a big problem. The calorifier that is connected to the system is fitted with a car radiator style pressure cap, marked '20' - presumably 20 PSI. When the cap lifts, it releases water from a spout into the bilge. The problem is that I am getting a steady drip of fresh water from the spout, even when the clarifier is cold. I know the easiest thing to do would be to fit another cap, but it seems that 20 PSI is quite a low relief pressure - many freshwater pumps seem to operate at a higher pressure than this. Also, would the fact that the accumulator is not working make any difference to the leakage?

Grateful for your thoughts.

Neil

 

[david_bagshaw]

`The accumulator not working will make the leak slightly worse, after all when the pressure switch turns off the pump undoubtedly continues even if for a part of a revolution, raising the pressure more, than the set cut off. however there might be a non return valve on the fill side of the hot water cylinder, then the expansion caused by the water heating up might cause the leak.

New canal boat supplied reservoirs are available on e bay. much more reasonable than jabsco etc

this one from midland chandlers

http://www.ebay.co.uk/itm/5-Litre-A...tEquipment_Accessories_SM&hash=item43c4a1cfbc


dont be tempted to use a heating expansion tank, as they deliver lots of rusty water.

 

[pvb]

IThe problem is that I am getting a steady drip of fresh water from the spout, even when the clarifier is cold.

Has this always happened? If not, perhaps you need to fit a new radiator cap. They're quite cheap, and you could perhaps also try a slightly higher pressure rating.
.

 

[superheat6k]

I had this dribble issue with my relief valve rated at 3 bar, but I couldn't find a 3 bar so replaced it with a 3.5Bar. The replacement I bought from ebay had a gauge connection to which I have fitted a small ball valve with flexi air line style hoe and trigger nozzle, which I can use to wash down the engine bay with hot water direct from the calorifier.

I would investigate replacing the car style cap with a brazed in brass plate with relief valve thread - typically 1/2" BSP Male or female. Whereas you would probably be OK with a 3.5 bar you should pressure test the system first to say 4 Bar. Certainly 20 psi (1.5 bar) is very low (could also be 2.0 bar 29 psi).

I have also replaced the old Jabsco Par belt driven pump as it was leaking through the diaphragm. This is sitting in my workshop waiting to be binned, just can't bring myself to do it, so if you want it for spares let me know.

For your accumulator it might be the bladderless type - this simply needs draining with the top cap open, the cap putting back in full of air then that resolves the issue for a couple of months. I will fit a bladdered type soon , along with a therm reg valve because the hot water after a run is coming out of the taps at around 85C, so is lethal.

 

[TradewindSailor]

Most domestic fresh water pumps are set at 45 psi. However if you have been running your system at 20psi you may end up with a few water leaks if you increase the pressure, particularly on the hot water hoses.