I went on a call last Friday (12-10-04) for a boiler that was leaking water from the pump and tripping the low water cut off. The seal was out of the pump and when you would turn it on water would spray all over the mechanical room, parallel pumps above the boiler. Removed the pump and valved off the lines to allow the boiler to run on one pump.
Removed the low water probe to check it out, found the low water cut off on the boiler was meant to be used on steam
instead of hot water, went to the supply house to get the right one and install it, that when the fun started. The new switch would go into lock out right away, water on the probe still trips out after taking it on on off about three more times I moved the junk they had stored by the floor drain and saw the water from the boiler it was so full of foam you could see thru it. I ran the pump with the drain open and the make up water bypass cracked to keep up the pressure for about an hour and restarted the boiler it fired and ran for twenty min. till it locked out again on low water. Repeated the hour long purge twice more and the unit stayed on. I also found that somebody had been jacking around with the chemical feed pump, shut the chemicals off to the boiler. This customer had just terminated their maintanance contract stating they" couldn't afford to spend the money" as I was leaving late friday night I thought what a waste, they cost themselves a pump and a bunch of overtime to save money.