But why would you want to prevent the boiler from cycling? There's nothing wrong with that. See #10.
Y plan bypass valve
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As I understand it, unless the TRV heads are linked to a modulating wall thermostat, then the boiler uses the return water to work out what output is required, and so unless water can return to the boiler, the boiler does not know what to do.
The boiler first reduces output as the return water temperature raises then it starts to cycle once minimum output has been reached so the return water is cool enough to gain the latent heat.
However since water must circulate for it to detect if heat required, it will never switch off completely. So although the TRV heads set the temperature for each room, without a wall thermostat the boiler would be cycling all summer. Nothing wrong with it cycling all summer, except it costs money.
Also the faster the boiler can get return water, the less time it needs to run for each time it switches on, so with a bathroom radiator with not TRV it has to push water to bathroom and back before it knows water is warm enough, but if there is a by-pass valve, it will be near or inside the boiler, so very fast the boiler realises it is not required, so on time is reduced, and energy waste also reduced.
So unless you want the boiler to always keep towel rail hot, then the by-pass valve is a better option, as it reduces boiler run time.
Having a wall on/off thermostat strategically placed can auto turn off the boiler in summer, the books say in a ground floor room with not alternative heating, and no outside doors, normally kept cool, last bit so thermostat can be set to a low heat so will not turn on heating when latter in the day home may over heat.
However in most homes the room does not exist, so we need to use a compromise, hall is normally kept cool, but it has an outside door, so if we have outside door, radiator, then thermostat, if we set the TRV on the radiator so the radiator will not turn off the wall thermostat in winter then in winter the heating will run, but in summer the wall thermostat is below ambient temperature so heating turns off.
The TRV on the radiator allows the radiator to reheat hall in winter after front door opened, but stop before it can turn off wall thermostat. And if wall thermostat is programmable then clearly also the TRV needs to be programmable to match.
I did this in late mothers house and it worked A1, however it does not work in this house, the problem is hall is centre of the house, and the official front door is never used, so although on heating it works, it's not the heating which is a problem, it is the cooling, hall is the last room on entrance level to cool, so in the evening at bed time temperature is reduced, and the hall becomes the warmest room in the house, so bedrooms become too cold, cure would be a wall thermostat linked to the coldest bedroom so even if hall warm enough the boiler still fires, or two wall thermostats, the latter is on my to do list.
As with most central heating my system is a compromise, yes we could have linked TRV heads in every room telling a central hub/thermostat when to turn on boiler, so 14 programmable TRV heads at £50 each and a wall thermostat/hub at £200 so £900 without fitting charge. At 70 years old unlikely more than 30 years to live, so is it worth spending out that sort of money to save a few pound on fuel bill, I don't think so.
The boiler first reduces output as the return water temperature raises then it starts to cycle once minimum output has been reached so the return water is cool enough to gain the latent heat.
However since water must circulate for it to detect if heat required, it will never switch off completely. So although the TRV heads set the temperature for each room, without a wall thermostat the boiler would be cycling all summer. Nothing wrong with it cycling all summer, except it costs money.
Also the faster the boiler can get return water, the less time it needs to run for each time it switches on, so with a bathroom radiator with not TRV it has to push water to bathroom and back before it knows water is warm enough, but if there is a by-pass valve, it will be near or inside the boiler, so very fast the boiler realises it is not required, so on time is reduced, and energy waste also reduced.
So unless you want the boiler to always keep towel rail hot, then the by-pass valve is a better option, as it reduces boiler run time.
Having a wall on/off thermostat strategically placed can auto turn off the boiler in summer, the books say in a ground floor room with not alternative heating, and no outside doors, normally kept cool, last bit so thermostat can be set to a low heat so will not turn on heating when latter in the day home may over heat.
However in most homes the room does not exist, so we need to use a compromise, hall is normally kept cool, but it has an outside door, so if we have outside door, radiator, then thermostat, if we set the TRV on the radiator so the radiator will not turn off the wall thermostat in winter then in winter the heating will run, but in summer the wall thermostat is below ambient temperature so heating turns off.
The TRV on the radiator allows the radiator to reheat hall in winter after front door opened, but stop before it can turn off wall thermostat. And if wall thermostat is programmable then clearly also the TRV needs to be programmable to match.
I did this in late mothers house and it worked A1, however it does not work in this house, the problem is hall is centre of the house, and the official front door is never used, so although on heating it works, it's not the heating which is a problem, it is the cooling, hall is the last room on entrance level to cool, so in the evening at bed time temperature is reduced, and the hall becomes the warmest room in the house, so bedrooms become too cold, cure would be a wall thermostat linked to the coldest bedroom so even if hall warm enough the boiler still fires, or two wall thermostats, the latter is on my to do list.
As with most central heating my system is a compromise, yes we could have linked TRV heads in every room telling a central hub/thermostat when to turn on boiler, so 14 programmable TRV heads at £50 each and a wall thermostat/hub at £200 so £900 without fitting charge. At 70 years old unlikely more than 30 years to live, so is it worth spending out that sort of money to save a few pound on fuel bill, I don't think so.
So what is the correct thing to do with this gatevalve, did you see the picture okay? The valve is currently closed at the moment is this safe/dangerous/inefficient will it affect the boilers performance in any way or will it be just fine? Thanks
Glad you've brought us back to the actual question!
As you have some rads without TRVs, I think it's fine to leave it closed. Of course you mustn't manually close the iso valves on all the rads without TRVs, but I'm sure you're aware of that.
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Yep, the radiator in the lounge doesn't have a trv as the main thermostat is in the lounge, plus the lounge radiator is the furthest away and its very large so there will be no chance it will ever be switched off at the valves. I generally never touch the ones in the bathrooms either except for when i was balancing the system but that is all done so i won't be touching them again.
Thanks
Good. Leave it that way. Maybe even remove the handle from it. Or just wait until the inevitable day that it seizes up completely.
Nothing will be damaged, there is no danger, and the absolute worst case is that the system will work just as it did before.
It may even work better now, as the circulation is all going via the radiators and not through the useless bypass that shouldn't have been installed in the first place.
Any size of radiator being left open will be far more effective as a bypass than a length of copper pipe.
Limescale where it's been leaking in the past.
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