Non condensing boiler temperature flow

[Razor]

The reason the second hour uses less gas is that the heating circuit is pretty much up to temp by then so the burner spends more time off.

The room thermostat is there to turn the heating off when it gets to temp. It's the programmers job to turn it on.

Because of your usage pattern you will not save as much by fitting a room thermostat as most people would. It sounds like the heating isn't on long enough to overheat the property anyway but you will still get benefits from having one, especially in the Autumn and Spring when the house will warm up much quicker.

[billbod]

The reason the second hour uses less gas is that the heating circuit is pretty much up to temp by then so the burner spends more time off.

The room thermostat is there to turn the heating off when it gets to temp. It's the programmers job to turn it on.

Because of your usage pattern you will not save as much by fitting a room thermostat as most people would. It sounds like the heating isn't on long enough to overheat the property anyway but you will still get benefits from having one, especially in the Autumn and Spring when the house will warm up much quicker.

Thanks Razor

I will definately look at a room thermostat this year. Then maybe wifi tvrs hahaha that aybe ankther thread entirely hahaha

[ericmark]

one rad should not have a tvr from what ive read , so at least I got that right hopefully .

Back in the 80's that was correct, but that was before the condensing boiler, the new system used all TRV's and a by-pass valve, so when the by-pass opens hot water returns to the boiler fast, so when the boiler cycles it can work out all the TRV's are closed due to speed that hot water returns, and so increase the off time.

However this assumes a rather simple algorithm used by the boiler, today boilers likely have a more advanced system.

As to 2 to 3 settings on the TRV's all mine show degrees C so can't really say what *123456 really means, but they open and close gradually, I hear the motors in mine work for a few seconds, except for midday Saturday when they exercise the valve, and it takes around 3.5 minutes to fully open then fully close, then return to setting.

I have some old mechanical heads in my desk draw, and it seems around 2 degrees between fully closed and fully open, hence why not marked in degrees C, so one room for 20 degs it may be 2.4 and another room 2.8 hence why numbers not degs C.

With such a small house my idea of selecting when rooms are heated seems a little pointless, but selecting when home held at 20 degs and when allowed to cool to 16 degs is still valid, most thermostats call the two temperatures eco and comfort, I would say four temperatures, the lowest is to stop things freezing and allow the home to reheat within a short time, in my case triggered when it detects neither my wifes or my phone is at home. (Called geofencing).

Next is over night, I don't like it too hot when in bed.

Then day time where we are moving around.

And finally the evening where we sit down to read a book or watch TV, in days gone by this was done with infrared from tungsten light bulbs which saved energy as we felt warmer without the air getting warmer, however the government does not want us to do this, so banned tungsten bulbs! Being far gas and oil is cheaper than electric so although using tungsten bulbs was energy saving, it was not money saving, as as long as heating is not resistive electric, LED lights save money.

However this means we want a thermostat with 4 temperature settings, but the mechanical thermostat be it wall or a TRV head, can only set one temperature.

I noted in some house the bedrooms can over heat, as heat raises, so the mechanical TRV does stop bedrooms over heating, and in my house if the wall thermostat turns down, it takes some time for the house to cool, so in the main except on very cold days, the boiler does not run over night as hall with wall thermostat in never gets cool enough.

I know with a non condensing boiler the on/off control does not really waste energy, but turning things on/off rather than up/down will produce some hysteresis, it surprised me, we would feel cold before the thermostat clicked back in, but there was only a 0.5 difference between off and on. So prefer to use the TRV's with a modulating boiler, but my boiler does not modulate, it produces 20 kW when running.

But still the pump runs even when boiler is off, so boiler maintains the water at around 60 - 70 degrees, but turning on/off, and the radiators stay warm even when boiler is off, until the wall thermostat turns off, only then will the radiators cool.

But the whole of the central heating system seems to work with near enough engineering, it costs too much to control spot on. Also working out costs when we mix fuels is near impossible, I remember my father-in-law telling me how much his solar panels saved him, and how his electric bill had gone down, but it turned out the solar panels were not working, what had happened he was heating DHW with gas instead of electric, we only found out when a smart meter was fitted.

No not due to reading meter, it was due to gas man not relighting pilot flame on boiler so he got no DHW, it was then we realised the solar panels were useless, and this was in the summer. Electric solar panels may work in North Wales, but DHW ones did not, worked well in daughters house in Turkey, but not North Wales.

This is also the big problem, we relate to our own home, but homes and live styles vary, so what works for me, may not work for you, so you need to work out what the CH is doing, and used some thought as to if it can be improved for you.

[AlwaysLearning]

The TRV settings are a bit of a red herring. Although you might think that "4" equates to 20C say, your perception of the room temperature is governed by factors such as air movement, relative humidity, solar gain, what you're wearing and your general health. Heat rooms to the level you feel comfortable and you'll see that a comfortable "3" in one room is a comfortable "just under 4" in another.

TRVs also have a hysteresis between on and off of perhaps 1.5C so if it is set to close when the air temperature reaches 20C, it won't reopen until 18.5C.

Another factor to be aware of is how heat moves. Assuming you have panel radiators, they radiate very little heat, but convect it. Cooler air is drawn up the radiator, up to the ceiling, it slowly cools, and drops down. The larger the temperature difference between the radiator surface and the air, the faster that air moves. You might also want to check behind the rads for build ups of fluff. Leaving doors open allows the air to circulate further and if the rooms are set to be at different temperatures, it exasperates the situation; hallway set for 17C, livingroom set for 21C, door open, you get the idea.

In an ideal world, your room heater would radiate warming up objects around it rather than convect. This is how underfloor heating works.

As for boiler temperature, just set it for as low as feels right for you. The lower the temperature, the longer it will take to get the rooms up to temperature. If it takes too long, just up the boiler temperature. And all of that is dependent on the outside temperature so you'll want hotter in the depths of a cold spell, and cooler when the weather warms up.