Items Covered This Month
• Swimming pool pump controller & thermostat monitor
• BWD 207b power supply
• The 5-minute PC fix – not
My first story this month comes from R. W. of Noosaville in Qld and concerns a number of interesting faults in his swimming pool control gear. I’ll let him tell it in his own words . . .
This saga covers a period of about eight years to the present. It all began when we moved into a 12-month-old house and had a pool installed.
To save me the chore of buying and decanting chlorine, we opted for a saltwater pool with a cell to generate the chlorine. We also opted for solar heating, as we hoped to swim for most of the year.
Things went well for about 10 months, then occasionally the pool pump would not start in the morning. The obvious “fix” was soon discovered – give it a gentle thump on the side of the control box and it would immediately spring into life!
However, with the 12-month warranty on the unit nearly up, we soon decided that thumping it was not the best answer and that it should be properly fixed. And so it was left with the local agent for a 100km round trip to the depot. They were very efficient because just four days later, the agent rang to say “it’s fixed, come and get it”.
When we went to retrieve it, we asked what the problem was but this only brought a blank stare from the lass in the pool shop. Oh well, if it’s fixed, why should we care.
Anyway, we re-installed the control box and all worked well for a couple of weeks. Then the intermittent fault returned. This time, having spent 25 years of my life as a service technician, I thought “what the heck – I can fix a simple thing like a pool pump controller”.
Disconnecting the control box from the motor, flow sensor and mains didn’t take long but clearing a place on the workbench took much more time. I then removed a couple of screws and the cover lifted off. It was nicely made, with a screened PC board, well laid out parts and rugged clip-on connectors.
Now what is the most common cause of intermittents that can be cured with a gentle tap? Yes, dry joints of course. There were none on the flow-soldered PC board but it was a different story when it came to the power transformer (a rather large PC-mount unit). The mains side was fine but the heavy secondary pins all had dry joints.
The solder joints themselves looked good but the solder had not adhered properly to the pins. I sucked the old solder away, gave the pins a good scrape with a sharp knife and carefully tinned them before resoldering them to the PC board.