Why does my boiler fire up when the cold tap is off?
Why does my boiler fire up when the cold tap is off?
Or more precisely, the boiler turned itself on briefly, a few seconds after we turned a cold tap off. This seemed very odd, because the whole point of a combie is that it only heats up the hot water when you need it.
Can you run a hot tap on a boiler?
For good measure (though now I realise maybe not so smart), I also ran the hot pipes part of the way from the boiler to the bathroom in 22mm, the rest in 15mm. What I now find is that running the hot tap on the basin or bidet does not make the boiler fire up, unless I run them both simultaneously (though the flow is not bad).
Why does a Combie fire up when the hot tap is turned on?
Because the trapped air acts like a bouncy cushion, when a cold tap is turned suddenly off, there’s a shock of water pressure that compresses the cushion of air, which tricks the combie into thinking that the hot tap has turned on. This means that to fix it, ideally you need to find a way to let out the trapped air.
Why does my shower have a hot tap?
Isolate it there and turn on the hot tap, if you still get water there is a pipe crossed, or the shower is allowing the mains water to back feed down the hot. Sounds silly, but put your ear up to the shower body and listen for water flow. FatHands likes this.
Or more precisely, the boiler turned itself on briefly, a few seconds after we turned a cold tap off. This seemed very odd, because the whole point of a combie is that it only heats up the hot water when you need it.
What to do when your boiler turns on when cold water is running?
Try turning cold water tap on very low checking the boiler and then slowly increasing and see if that fires up boiler, and also try is flushing the toilet. Not normal. Call your RGI to rectify.
Because the trapped air acts like a bouncy cushion, when a cold tap is turned suddenly off, there’s a shock of water pressure that compresses the cushion of air, which tricks the combie into thinking that the hot tap has turned on. This means that to fix it, ideally you need to find a way to let out the trapped air.
Why does a short cycle boiler fire up?
The internal thermostat of a short cycling boiler will detect that the water in the heat exchanger is cooling and, although the temperature in your home has not dropped, fires up the boiler to reheat the water.