High gas bills - possible meter issue?

nigelbb

Uxb1 wrote: »

I've had TRV's on all radiators since day 1
that's about 30 years.
There is no room thermostat
The boiler comes on an off depending on its own internal thermostat - provided of course the timer is on.
If all the TVR's went off (which actually will never happen) then the pump would pump water round the bypass loop which would open the bypass valve and the boiler would see return water at the same temperature as the outgoing water and switch off.
Indeed the boiler cycles on and off regularly when in use as the return water temperature varies depending on how much heat is lost round the system pipes and radiators - if heat is not required then the pump continues to pump the water round the system with no extra heat from the boiler applied.

This is exactly the system we have which does not require a redundant room thermostat.

nigelbb

thorganby wrote: »

Yet you have returned with a totally incorrect post which shows why you definitely should not have bothered!

Why post about something that you obviously do not understand.

I think that it's you who obviously doesn't understand how the system actually works as described by Uxb1 & what we have in our house

Uxb1 wrote: »

I've had TRV's on all radiators since day 1
that's about 30 years.
There is no room thermostat
The boiler comes on an off depending on its own internal thermostat - provided of course the timer is on.
If all the TVR's went off (which actually will never happen) then the pump would pump water round the bypass loop which would open the bypass valve and the boiler would see return water at the same temperature as the outgoing water and switch off.
Indeed the boiler cycles on and off regularly when in use as the return water temperature varies depending on how much heat is lost round the system pipes and radiators - if heat is not required then the pump continues to pump the water round the system with no extra heat from the boiler applied.

thorganby

nigelbb wrote: »

I think that it's you who obviously doesn't understand how the system actually works as described by Uxb1 & what we have in our house

Two wrongs don't make a right.

TRV's do not make rooms stats redundant. TRV's simply prevent the room getting hotter than required.

A room stat is more important than TRV's.

Room stats have been fitted by proper installers for many decades and at least one is required by Part L building regs and are a legal requirement.

If you don't have a room stat you have an inefficient system fitted by a cheapskate cowboy installer but you obviously think that you are right and the regs are wrong!

A room stat prevents the boiler cycling unnecessarily, forcing heat around the bypass and wasting fuel when the building is already at, or above the target temperature.

As I said you don't understand.

Talldave

Uxb1 wrote: »

I've had TRV's on all radiators since day 1
that's about 30 years.
There is no room thermostat
The boiler comes on an off depending on its own internal thermostat - provided of course the timer is on.
If all the TVR's went off (which actually will never happen) then the pump would pump water round the bypass loop which would open the bypass valve and the boiler would see return water at the same temperature as the outgoing water and switch off.
Indeed the boiler cycles on and off regularly when in use as the return water temperature varies depending on how much heat is lost round the system pipes and radiators - if heat is not required then the pump continues to pump the water round the system with no extra heat from the boiler applied.

Fascinating! Does the internal thermostat measure ambient temperature or the return flow temperature? I would have thought that the boiler is pointlessly cycling on and off a lot?

Edit: ah, it seems that thorganby has put much more eloquently what I was thinking. Feeling slightly less guilty at calling such systems crap now! Especially as they'd be illegal under current regulations.

nigelbb

thorganby wrote: »

Room stats have been fitted by proper installers for many decades and at least one is required by Part L building regs and are a legal requirement.

If you don't have a room stat you have an inefficient system fitted by a cheapskate cowboy installer but you obviously think that you are right and the regs are wrong!

A room stat prevents the boiler cycling unnecessarily, forcing heat around the bypass and wasting fuel when the building is already at, or above the target temperature.

A central heating system with a TRV on every radiator & no thermostat was common twenty years ago & this is the system we have in our large Victorian house.

As I understand it building regulations do not specifically require a thermostat but do require a control interlock so that when there is no demand for either space heating or hot water the boiler and pump are switched off. This can be a thermostat, a flow switch or whatever. There are boilers with integral flow switches so that TRVs can be fitted on all rads. When the TRVs are all closed the boiler switches off via the flow switch. The boiler periodically tests the to see if the TRVs have opened up. So with these boilers no toom stat is needed. Other methods of control interlock are sensing the temperature differential between flow and return. If narrow then the boiler switches off.