b'FEATUREStop Wasting EnergyStop Steam LossBy Bruce Grossman, EZ Timers Manufacturing THISISSUEILLBETALKINGABOUTHOWTOLOCATE check valves, causing them to partially fail and allowingFAULTY CHECK VALVES IN YOUR BOILERS CONDENSATE water to be pushed out of the boiler pressure vessel intoRETURN SYSTEM. The purpose of a check valve is to limit the return tank. This valve blow by is costly in wastedthe flow of water to one direction which is usually energy, with steam boiling away in the return tank. Inindicated by an arrow stamped into the body of the addition, the superheated water forced into the returnvalve. These types of valves are used between the boiler tankoverheatsthewaterinthereturntank,oftenreturn pump and the boiler pressure vessel, with the causing the return pump to cavitate and lose its abilitydirection of flow towards the boiler. When the boilers to refill the water in the boiler pressure vessel. Whenwater level drops lower than the pump activation sensor, the water level drops low enough, the boiler will shutthe pump motor turns on and the pump pulls water down on a low-water fault, causing an expensive loss offrom the return tank and pushes it through the check plant production capacity due to boiler down-time.valves into the pressure vessel of the boiler.For these reasons, its a good thing to monitor yourThe filling continues until the water level reaches the check valves performance and replace them when theypump de-activation sensor and the pump turns off. fail. Fortunately, its easy to run a simple temperatureHowever, there is pressure in the boiler pressure vessel test to accurately predict a valves condition. Afterand there needs to be some method to prevent this operating the boiler for a couple of hours wait for thepressure from pushing the water back out of the boiler pump to go on. Immediately after it shuts off, turn offpressure vessel into the return tank. This is what check power to the pump. Now wait between 90 seconds andvalves do. When the pump is off, accumulated pressure two minutes. Using a laser thermometer as describedinside the boiler holds them shut, preventing water below, measure the temperatures at the points indicatedfrom being forced out of the boiler pressure vessel.on the accompanying illustration. There should be atUnfortunately, steam systems generate a lot of scale, least a 30F difference in temperature between the twosince steam and return pipes continuously shed large points.differenceintemperaturebetweenthetwoparticles of rust as well as other bits of metal. This points. If there is less, its an indication the check valvedetritus often finds its way into the internals of the has a problem. Experience has taught me that it doesntcontinued on page 30THIRD QUARTER 2019 29'