5th September 2025 - Pump Problems

Happily, due to external issues the garage was not visited again for a few days and, in that time, the spilled water had managed to evaporate. The task at the top of the agenda was to see what was wrong with the pump. Diconnecting the hotwell was the first mistake of the day as it had no valve on it (yet!) and water began leaking everyhere. The joint was quickly remade and a slim handled paint brush handle was used as an emergency plug inside the hot well. That reduced the flood but did not stop all the water in all the pipes from draining back out onto the floor.

After much mopping up the pump was disconnected and then dismantled. It was found that the piston's O ring had a small piece of swarf caught under it. Presumably this was sufficient for the piston to leak water back into the other end of the cylinder. The swarf was removed and a careful check was made to see if there was any more lurking. At the same time it was noticed that the piston's other ring was a flat cross section split ring. The split was wide open so clearly that ring was doing nothing to retain pressure.

The pump was re-assembled and then the whole set up was put back together. The hot well was re-filled and the test routine was begin again. The manifold drain was left open to start and, as previously, it delivered a slug of black sludge and then the water flowed clear. The valve was then closed and pumping continued with more effort required. At each stroke the pressure gauge climbed and there were no signs of drips, leaks or sprays. Soon 100psi had been passed and the pressure went on up.

**Hydro Success!**

Pumping was getting harder but the goal of 185 psi was reached and a photo taken. However, the elations was somewhat dimmed by the hissing noise at foot level. Something was voiding the hard won pressure. A feeling of dampness in the feet soom gave a big clue as to the source. The pump had failed again and was squirting out water from the cylinder vent.

It had been the intention to leave the system pressureised to see how long it could remain at a high pressure. However, since the pump had let us down again, it is was simply a case of having to set to work mopping up again.

**Pump failure again.**

At this stage it seemed sensible to do some reflection. Why had a hydro test been done? The object is, presumably, to ensure that the system has no leaks. That objective had clearly been achieved albeit over several "re-sit" tests. What pressure should the hydro test reach? In the various articles in Funnel taking the test to twice planned operating pressure is mentioned. However, in a recent SBAS Newsletter in Funnel 206 it was suggested that 1.5 times working pressure would be sensible for periodic hydraulic inspections.

Thus it would seem safe to conclude that the boiler system had been shown to be sound enough to be offered for SBA inspection without risk to the inspector.

Clearly some problems remain to be sorted out. Firstly the pump needs to have fresh suitably sized O rings fitted. Secondly, the non return valve on the pump outlet side requires examination as it was leaking back rather than holding the system pressure. The final test that probably ought to be done is to re-fit the safety valve and do another pressure test to check that it releases the pressure at the marked 90 psi level. Once all that is done the pipework can then be fitted back into the casing and re-tested for leaks.