Boiler firing every time a hot tap is used?
Discussion
Hi All
We had a new boiler installed last December.
It’s a Worcester 30Ri fwiw
Anyway, if the program is set to be producing hot water say 7am-10am and someone uses a hot tap it immediately fires up some times for a matter of seconds I assume to top the tank up. Sometimes I hear what sounds like a micro switch clicking on and off - boiler is in a cupboard in the kitchen.
Is this normal? Seems mad to fire up for a mug full of water, surely a threshold of say 20L would be more appropriate and efficient. I don’t remember the old boiler behaving in this way.
We had a new boiler installed last December.
It’s a Worcester 30Ri fwiw
Anyway, if the program is set to be producing hot water say 7am-10am and someone uses a hot tap it immediately fires up some times for a matter of seconds I assume to top the tank up. Sometimes I hear what sounds like a micro switch clicking on and off - boiler is in a cupboard in the kitchen.
Is this normal? Seems mad to fire up for a mug full of water, surely a threshold of say 20L would be more appropriate and efficient. I don’t remember the old boiler behaving in this way.
You may have done a typo as their own website calls this a "Worcester Bosch Greenstar Ri 30 kW Natural Gas Heat Only Boiler 7733600066" indicating that it is a central heating boiler only.
It goes on to say.
"This heat-only boiler is a wall-mounted natural gas unit designed to provide central heating in residential and light-commercial installations. It operates as a dedicated heating appliance delivering steady heat output while occupying minimal wall space, making it suitable for installations where a separate hot-water system is already in place."
It goes on to say.
"This heat-only boiler is a wall-mounted natural gas unit designed to provide central heating in residential and light-commercial installations. It operates as a dedicated heating appliance delivering steady heat output while occupying minimal wall space, making it suitable for installations where a separate hot-water system is already in place."
E-bmw said:
You may have done a typo as their own website calls this a "Worcester Bosch Greenstar Ri 30 kW Natural Gas Heat Only Boiler 7733600066" indicating that it is a central heating boiler only.
It goes on to say.
"This heat-only boiler is a wall-mounted natural gas unit designed to provide central heating in residential and light-commercial installations. It operates as a dedicated heating appliance delivering steady heat output while occupying minimal wall space, making it suitable for installations where a separate hot-water system is already in place."
Heat only boilers also supply hot water. They are a type of boiler designer to work with traditional hot water cylinders.It goes on to say.
"This heat-only boiler is a wall-mounted natural gas unit designed to provide central heating in residential and light-commercial installations. It operates as a dedicated heating appliance delivering steady heat output while occupying minimal wall space, making it suitable for installations where a separate hot-water system is already in place."
If its a combi, then it will fire every time you turn on the tap, thats literally how half the boilers in the country work.
However if its a system boiler, or 'heat only' boiler, ie there is a hot water tank. Then that sounds like very strange behaviour.
A) do you have a hot water tank
B) is it currently warm to the touch
C) are you sure you don't now have a combi
However if its a system boiler, or 'heat only' boiler, ie there is a hot water tank. Then that sounds like very strange behaviour.
A) do you have a hot water tank
B) is it currently warm to the touch
C) are you sure you don't now have a combi
dhutch said:
If its a combi, then it will fire every time you turn on the tap, thats literally how half the boilers in the country work.
However if its a system boiler, or 'heat only' boiler, ie there is a hot water tank. Then that sounds like very strange behaviour.
A) do you have a hot water tank
B) is it currently warm to the touch
C) are you sure you don't now have a combi
Hi AllHowever if its a system boiler, or 'heat only' boiler, ie there is a hot water tank. Then that sounds like very strange behaviour.
A) do you have a hot water tank
B) is it currently warm to the touch
C) are you sure you don't now have a combi
Thanks for all the replies.
I have a Megaflo unvented cylinder in the loft so 100% not a combi boiler.
Was the cylinder new too? Has it done this from the start?
Indirect cylinders and system boilers aren't complicated so it's most likely either a badly set thermostat right at the upper limit, a bad thermostat that just doesnt work well, a badly installed thermostat so it's not measuring correctly or some dodgy installation so the incoming cold water is somehow chilling the sensor rather than being nice and stratified at the bottom.
Either way it's unvented which makes it best left to someone competent to sort.
Indirect cylinders and system boilers aren't complicated so it's most likely either a badly set thermostat right at the upper limit, a bad thermostat that just doesnt work well, a badly installed thermostat so it's not measuring correctly or some dodgy installation so the incoming cold water is somehow chilling the sensor rather than being nice and stratified at the bottom.
Either way it's unvented which makes it best left to someone competent to sort.
I am just wondering why your hot water heating is on all day?
My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
Actual said:
I am just wondering why your hot water heating is on all day?
My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
Ours is on from 5am-10pm. It does most it’s heating at 5am, then tops up if needed. It’s such a negligible cost I wouldn't see the point in limiting it and potentially having luke warm water in the evening. My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
Actual said:
I am just wondering why your hot water heating is on all day?
My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
Even if the timer is on, the boiler won't come on to heat the hot water unless you are using lots. Once up to temperature the insulation on a modern cylinder will keep the water hot for days.My house has an oil boiler and a Megaflow unvented tank. HW is controlled by a timer which is only on 07:00 to 08:00 and then by a thermostat. I wouldn't notice if running a tap caused the boiler to fire because the HW is either legitimately heating or it is off.
Due to the current cost of oil I now heat the hot water overnight using the immersion heater and a low cost EV tariff rate.
Mike Legerwood said:
Even if the timer is on, the boiler won't come on to heat the hot water unless you are using lots. Once up to temperature the insulation on a modern cylinder will keep the water hot for days.
I’d prefer the boiler to have a good run at reheating the hot water, rather than go through multiple boiler cycles each time there’s a demand to reheat the cylinder. Our boiler seems to idle for ages once it’s hit the boiler stat so all it’s doing then is cooling the water in the tank until it refires.
We have ours on for a couple of hours in the morning and that’s it. If my wife wants a bath in the evening there’s still more than enough hot water and then the boiler gets a good run next morning.
Obviously other’s use cases may vary. If our grandchildren are staying we tend to just leave it on.
8-P said:
Hi All
We had a new boiler installed last December.
It s a Worcester 30Ri fwiw
Anyway, if the program is set to be producing hot water say 7am-10am and someone uses a hot tap it immediately fires up some times for a matter of seconds I assume to top the tank up. Sometimes I hear what sounds like a micro switch clicking on and off - boiler is in a cupboard in the kitchen.
Is this normal? Seems mad to fire up for a mug full of water, surely a threshold of say 20L would be more appropriate and efficient. I don t remember the old boiler behaving in this way.
Sounds like a fault. The boiler should only fire when the hot water from the tank has drained sufficiently to warrant the thermostat in the tank sending a signal to the boiler to wake up. We had a new boiler installed last December.
It s a Worcester 30Ri fwiw
Anyway, if the program is set to be producing hot water say 7am-10am and someone uses a hot tap it immediately fires up some times for a matter of seconds I assume to top the tank up. Sometimes I hear what sounds like a micro switch clicking on and off - boiler is in a cupboard in the kitchen.
Is this normal? Seems mad to fire up for a mug full of water, surely a threshold of say 20L would be more appropriate and efficient. I don t remember the old boiler behaving in this way.
You could probably work around the issue for the time being by using the hot water timer so that the hot water is off when people are awake or at home and using taps.
dhutch said:
I can't event see how a system or hest only boiler could fire in response to the tap being operated. The system wouldn't have any flow or pressure detection capability to event know. Hence wondering if the OP has actually somehow had a combi boiler fitted.
Don't think it will be a combi as the CH wouldn't work via the mega flow? And the OP can check the model details online anyway and I assume has done so. I'm certainly not any kind of heating engineer by a long shot but I'd start with the thermostat and then the valves as something on the mega flow side is sending a signal to the boiler erroneously?
dhutch said:
I can't event see how a system or hest only boiler could fire in response to the tap being operated. The system wouldn't have any flow or pressure detection capability to event know. Hence wondering if the OP has actually somehow had a combi boiler fitted.
If it's a mains pressure indirect cylinder as we're all assuming, based on what the OP says, then we would assume the only sensor in the game is a cylinder thermostat?So maybe the question is, does the cylinder thermostat switch every time a tap goes on?
If so, why is that?
My only suggestion would be that the tank thermostat is very sensitive to incoming cold water? Maybe it has no hysteresis, maybe it's in the wrong place, maybe the tank is plumbed wrong?
If the OP has anything fancy like circulating HW to give quicker hot at the tap then more possibilities exist for embuggeration?
So, subject to the usual warnings about remote diagnosis by interweb, I would look at the tank thermostat and attempt to observe what's happening.
Does the tank have air space in the top? wrong amount of air?
(anyone got a handy 'fault finding chart image', where all routes lead to 'replace the plumber'?)
:-)
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