My boiler is about 7 years old, so not too old. But a few times in the last year, we've had to call out a plumber because the water pressure keeps dropping and it trips something inside. We have to top it up every 3 weeks or so - is that normal??? And what could be causing it? There's no noticeable sign of a leak anywhere. Is a leak the only reason the pressure could be dropping so quickly?Thanks!
Is this a forced hot water system or steam? If it's forced hot water then you are loosing water some where in a place that can't be noticed right away. The biggest culprit for closed systems is the expansion valve. When the water gets too hot it expands and builds up pressure. The valve is designed to open and relieve some pressure. Along with the pressure it also releases some water. You should have an automatic feed to keep the water at a level in the boiler. If the system is steam then I suspect the problem is do to faulty air valves on the radiators. The air valves open when pressure starts building up in the system. This way the air in the lines is exhausted into the atmosphere allowing the steam to fill the system. When the valve is hot and the pressure is up the valve shuts off. If they stay open they allow some steam to escape and the water in the steam vapor is let into the air. The water vapor in the steam is suppose to condense and flow back into the boiler. If over a period of a couple of weeks the condensation is lost and you have to replenish the system. You can ask your service man about changing out the valves or do it your self if you are handy. You do not have to tighten the new valves too tight only snug, and use a little teflon tape. Theu are around $6.00 to 8.00 bucks a piece. They also have adjustable ones to control the amount of air it releases to control the heat. These are around $18.00 a piece. Add more info to you question if more help is needed
I think dry air of winter is evaporating some of the water. As it evaporates it gets lower and lower until the low water safety switch is engaged. Good luck
The expansion tank has a bladder inside that compensates for the changes you speak of. It may need replacement if the bladder is losing air. Have your service tech check it next time.
you might want to check the expansion tank. If the expansion tank is damaged, it could cause the systenm pressure to drop
