Hi. I would be very grateful for any help please.
I have a hot water cylinder that is heated primarily by a gas boiler. I also have an immersion heater in the cylinder attached to a timer.
I have solar panels and a 10kwh storage battery and so usually have a lot of surplus and/or saved electricity and so I usually have the immersion come on at night and then again early afternoon (say, 2pm ish) with the intention to not often need the gas boiler to come on to heat the water because I can do it with free solar/stored energy. The gas boiler is on a timer so that it will kick in to heat the water at 4.30pm-5.30pm either if the water in the cylinder needs the temperature topping up or if, for any reason, i haven't used the immersion earlier that day/previous night.
On recent occasions when i have heated the cylinder overnight and then switched it on again in the early afternoon (in the afternoon the cylinder is usually hot enough so that the immersion only needs to be on for a short time - approx 1 hour is usually enough. 2 hours is the absolute maximum needed) to get the water back up to temperature (the temperature dial at the bottom of the cylinder is set to 65 degrees C). I am finding that the gas boiler still kicks in at 4.30pm despite the immersion having heated the water up to temperature only an hour before and is staying on for the hour that it is set for.
My query is why is the gas boiler still kicking in to heat the water? I had the immersion on overnight to ensure the water was up to temperature, so that would have gone off around 4am. Then at around 2pm the immersion has been switched on again to ensure the water is still at the maximum temperature. Usually the immersion switches itself off about 2.30pm because the water only needed a brief boost to get it hot again. So then at 4.30pm I would either expect the boiler to NOT kick in for hot water or, if it did, to only kick in very briefly to get the (already hot) water up to the maximum temperature.
Could someone please help me understand what is happening here and if there are any adjustments i need to make. Is the boiler possibly sensing that the water in the cylinder is below a temperature that it is aiming for and therefore is still trying to heat the already hot water up even more? If so, how do i adjust that?
In addition, i was trying to work out was going on and so I switched the boiler off for the day and put the immersion on overnight (went off around 4am) and then switched the immersion on for an hour again at around lunchtime. So all the while the gas boiler is completely switched off and only the immersion has been used to heat the water (and the cylinder has got very hot after each time - indicating it has been heating up as expected). Yet that evening when having a shower there was only limited hot water for a short while and then the water started to get noticeably cooler. Not cold, but lukewarm. I would have expected the water to still be pretty hot from about 6 hours previously.
The cylinder and boiler are all pretty new (about 4 years old). The house was built in 2019 and there have been no indications of any problems with the boiler, cylinder or immersion. And the cylinder is well insulated. I watch the timer for the immersion and the energy readings on my PV / solar app when the immersion is on and when it switches off and it seems to be operating fine. So I am just curious about the boiler still kicking in when the water is seemingly hot and also why the water is only lukewarm after a few hours when the boiler is off yet the immersion has been on during the day.
Any help would be greatly appreciated. Many thanks
I have a hot water cylinder that is heated primarily by a gas boiler. I also have an immersion heater in the cylinder attached to a timer.
I have solar panels and a 10kwh storage battery and so usually have a lot of surplus and/or saved electricity and so I usually have the immersion come on at night and then again early afternoon (say, 2pm ish) with the intention to not often need the gas boiler to come on to heat the water because I can do it with free solar/stored energy. The gas boiler is on a timer so that it will kick in to heat the water at 4.30pm-5.30pm either if the water in the cylinder needs the temperature topping up or if, for any reason, i haven't used the immersion earlier that day/previous night.
On recent occasions when i have heated the cylinder overnight and then switched it on again in the early afternoon (in the afternoon the cylinder is usually hot enough so that the immersion only needs to be on for a short time - approx 1 hour is usually enough. 2 hours is the absolute maximum needed) to get the water back up to temperature (the temperature dial at the bottom of the cylinder is set to 65 degrees C). I am finding that the gas boiler still kicks in at 4.30pm despite the immersion having heated the water up to temperature only an hour before and is staying on for the hour that it is set for.
My query is why is the gas boiler still kicking in to heat the water? I had the immersion on overnight to ensure the water was up to temperature, so that would have gone off around 4am. Then at around 2pm the immersion has been switched on again to ensure the water is still at the maximum temperature. Usually the immersion switches itself off about 2.30pm because the water only needed a brief boost to get it hot again. So then at 4.30pm I would either expect the boiler to NOT kick in for hot water or, if it did, to only kick in very briefly to get the (already hot) water up to the maximum temperature.
Could someone please help me understand what is happening here and if there are any adjustments i need to make. Is the boiler possibly sensing that the water in the cylinder is below a temperature that it is aiming for and therefore is still trying to heat the already hot water up even more? If so, how do i adjust that?
In addition, i was trying to work out was going on and so I switched the boiler off for the day and put the immersion on overnight (went off around 4am) and then switched the immersion on for an hour again at around lunchtime. So all the while the gas boiler is completely switched off and only the immersion has been used to heat the water (and the cylinder has got very hot after each time - indicating it has been heating up as expected). Yet that evening when having a shower there was only limited hot water for a short while and then the water started to get noticeably cooler. Not cold, but lukewarm. I would have expected the water to still be pretty hot from about 6 hours previously.
The cylinder and boiler are all pretty new (about 4 years old). The house was built in 2019 and there have been no indications of any problems with the boiler, cylinder or immersion. And the cylinder is well insulated. I watch the timer for the immersion and the energy readings on my PV / solar app when the immersion is on and when it switches off and it seems to be operating fine. So I am just curious about the boiler still kicking in when the water is seemingly hot and also why the water is only lukewarm after a few hours when the boiler is off yet the immersion has been on during the day.
Any help would be greatly appreciated. Many thanks