Central heating

What is this pump and what does it do .
circulates the water.
And what is the best number to have it on .
lowest that will work
2nd my heat does not seem to turn down .
this is controlled by the thermostatic radiator valve (TRV) and lock shield valve in the main.
Should the valves on the radiators be fully open .
No.

So the system is, the pump circulates the water either through the radiators if the TRV is open, and the by-pass valve if all TRV's are closed, and the boiler monitors the return temperature and adjusts output, so the return water is cool enough to gain the latent heat from the flue gases.

This system has a flaw, the boiler would never switch fully off, it would cycle off/on all the time, so we try to include a method to turn it fully off, the traditional method was to put a wall thermostat in a downstairs room, with no alternative heating, and normally kept cool, and no outside doors, there is often no such room. So there are other methods, like the TRV linked to a hub, and the hub turns the boiler on/off, or up/down if that type of thermostat.

The boiler often does more than heat one set of rooms, either zones of rooms, or room and domestic hot water (DHW) and to do this we have zone valves, inside the zone valves there is often a micro switch and if that switch sticks closed, then the boiler will not stop running.
 
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I have this one . But it's near the front door . Probably the coldest part of the house . Is this why the radiators are so hot . Because this is cold .

As a check - turn that thermostat down to minimum, less than 10 then check you radiators, after an hour. They should all be completely cold.
 
I have this one . But it's near the front door . Probably the coldest part of the house . Is this why the radiators are so hot . Because this is cold .
The lockshield valve. Should I have this fully open mate . Sorry to be a pain . I'm a joiner and this is all new to me .
Cheers mate
Had same problem with mother's house, long large radiator along the wall, then a doorway, then the thermostat then another door. Theory is great, but to get circulation with a staircase opposite the radiator is simply not going to happen. So close the lock shield valve, so rest of house can heat up, and open door, and hall freezing cold, open up the lock shield valve, so hall is warm, and rest of house is cold.

Only method seemed to be to fit a thermostatic radiator valve (TRV) the mechanical TRV has a massive droop, (difference between on and off temperatures) and it is analogue, so set at say halfway between 2 and 3, it would start to close at 17°C and not fully close until 20°C so a wall thermostat set at 19°C would switch off in fullness of time, but it would take long enough so rest of house warm first, but from 6°C after door opened to 17°C recovery was fast. This was OK with a simple warm thermostat.

But I moved to a programmable thermostat, so now for it to work, the TRV also needed to be programmable, this is more of a problem, as the droop on an electronic TRV head is more like 1°C not 3°C, so it becomes harder to set up. So start to look at linked TRV heads, the Drayton Wiser system will auto combine the wall thermostat and TRV head if both assigned the same room name, and the Kasa TRV head can have remote sensors to control it.

The main problem, is the installers, don't live in the homes they install the systems into, except their own home, and users often have no idea of the options available. To get someone to say, I have use Tado, Tapo (Kasa), Evohome, Wiser, Hive etc. And you set it up like this, seems to be rare, we get the "we do it this way, because we have always done it this way." brigade, who are still living in the 80's before we had condensing boilers, I have also worked with the old one pipe system, steam goes in one end, water drips out the other, but only because a work on a heritage railway, where boilers still boil water, today if a boiler boils water we consider it faulty.

So in my house I have eQ-3, Energenie, Kasa, and Wiser TRV heads, I got it wrong to start with, was told Energenie worked with Nest, it does no work any more, when I got them eQ-3 were cheap, (£15 each) and I used Kasa as already using Tapo, both are TP-Link so use the same hubs, but Wiser transformed my system, it works, so once I got it working, did not need to try anything else.

Having a wireless thermostat that you can take room to room, or move around the room, to test where is the best place, is a huge advantage, until the cat sleeps on it and one is left scratching one's head why is the room so cold.

But my first two homes worked well, both open plan, so a single thermostat was enough, mother's house and this house had the thermostat in the hall, silly single place really, but one has to look at 1970's houses to understand why, the central heating was to get the home warm in the morning, before going to work, or evening having just got back, but main heating was still the open fire in the living room, at that time we wanted the living flame, central heating back then was only to warm house while one laid and lit the fire, so a thermostat in the living room would not work, as the fire would stop central heating working in any other rooms.

But today is all about each room being its own zone, with a thermostat in every room, OK that thermostat may be a TRV, but the whole concept has moved on.
 
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