Central Heating Advice

[Xesh]

We have a conventional (non combi) boiler (baxter) and hot tank set up powering seven radiators throughout the house. The boiler is controlled by a basic digital timer with no internal thermostat........

Sounds like you have the same setup as me along with one of the same problems that I have.

The only thing is my tank thermostat is knackered and I need to replace it. The other thing is that I think the whole system has been plumbed in weirdly. Even if I switch off the heating on the controller but leave the hot water on the rads still heat up! I've had the controller tested and it's fine. It's so bad that I also have to switch off the hot water in the summer to stop myself roasting.

Luckily it's not my problem any more as I sold the house and can get the new owner to do it.

 

[FluffyChicken]

As I said, rads are either on or off, there is no middle ground, although if the valves are part closed, the flow will be restricted slightly. The stat on the boiler sets the max water temp in the system (ie radiator temp & hot water temp). The stats on the rads detect room temp & will stop the watr=er flow on that rad when the room reaches the set valve temp.

If you reduce the valve stat settings it may take the room several hours to cool down.

Ahh.

So the whole shebang will be controlled by the dial on the boiler :? I know this appears to be a stupid question but.....

The boiler controls the temperature of the water coming out of it, which should be ~60/65decC for modern systems and will be the temp of the water in your radiators, it as mentioned above shuts the whole boiler flow of when the retrun reaches the same temp, but this is the same for combination boilers as well (hence why you need to have one radiator always open, else if they shut of it has to use the internal bypass) But from what you are now saying this is not the problem.

If at setting 3 on your radiator and it's not stopping at about 18 to 21 degC then there is something wrong with them OR there are obstruction stopping the airflow getting to them like you radiator is behind the chair or sideboard.
The top should be screwed on reasonably tight, it's best put on with it in the 5 position (or max temp). Also unless they are expensive TRV's (thermostatic radiator valves) then you'll hear the restriction of water flow.

Try swapping the tops around.

You can alter the other valve on the radiator to also restrict the flow but this alters the balance around the house as well.

Some boilers have a capacity value, not sure what that is for, but turn it to minimum if your not heating upstairs and have it turned off.


I'm surprised you don't have a room thermostat, to actually control the boiler (note don't put it in a room with a TRV radiator, since the TRV may switch the radiator of and the boiler will never turn off )
(side note if your are updating your system you technically have to get a thermostat fitted under building regulations)

 

[FluffyChicken]

Found this site that explains a lot of things, has picture too so much better than me talking from my feeble knowledge gained over the years.

 

[letmetalktomark]

Found this site that explains a lot of things, has picture too so much better than me talking from my feeble knowledge gained over the years.

Which website?

 

[ragnar1984]

The boiler controls the temperature of the water coming out of it, which should be ~60/65decC ...

I had problems with this when I got a new boiler a couple of years ago. The plumber (who should have known better) set the thermostat on the boiler to 85°C. My radiator thermostats stop functioning when the inlet water is above ~65°C, then they stay fully open at all times. I just turned down the thermostat on the boiler to lower the temp of the outgoing water and my radiator stats started working again.

 

[kaiser]

Found this site that explains a lot of things, has picture too so much better than me talking from my feeble knowledge gained over the years.

Which website?

Fluffys mentioned this one before


http://www.hairyarsedplumbersinsussies.net

 

[FluffyChicken]

Found this site that explains a lot of things, has picture too so much better than me talking from my feeble knowledge gained over the years.

Which website?

<slaps head>

Must remember to actually post the link
http://www.gasman.fsbusiness.co.uk/controls.htm


Have it known I'm not a plumper, I have fitted our radiators and all the pipe work and work out a few systems, a family member has been a plumber for a long time and I've just picked up a few things in talks. I would seek professional advice if you really want to know though or get really stuck.

I have used this forum for other things, not the plumbing & heating part, they have a wiki too (direct link to heating part)
http://www.diynot.com/forums/viewforum.php?f=7

 

[llamedos]

If I was to remove the thermostatic valve bit off of the radiator valves should I be able to replace them with newer thermostat bits without actually any plumbing nonsense.

E.g. below is a picture of what we have (but slightly newer). If I was to buy one and remove the plastic thermostat cap should it work in theory on the metal body of what I have in place?

In short no .....
Sounds funny that all the valves don't work ... I wonder if somebody has already swapped bit's around ... you should feel some resistance when you screw down to 0 ... also no heat should be going through the rad, if at 0 they all still get hot and the tops are screw correctly to the valve then something is screwy

 

[Back2Bikes]

We have a conventional (non combi) boiler (baxter) and hot tank set up powering seven radiators throughout the house. The boiler is controlled by a basic digital timer with no internal thermostat........

Sounds like you have the same setup as me along with one of the same problems that I have.

The only thing is my tank thermostat is knackered and I need to replace it. The other thing is that I think the whole system has been plumbed in weirdly. Even if I switch off the heating on the controller but leave the hot water on the rads still heat up! I've had the controller tested and it's fine. It's so bad that I also have to switch off the hot water in the summer to stop myself roasting.

Luckily it's not my problem any more as I sold the house and can get the new owner to do it.

For general info, the continued heating of rads when set to HW only is generally due to back flow. You have a system with a flow & return but the stop valve is only in one leg. This should cut off all flow in the circuit, but there are always "other paths" where the water can back flow thro some rads so these will continue to warm up. It can be stopped if you want to install one way valves or angled tee's.

 

[llamedos]

"For general info, the continued heating of rads when set to HW only is generally due to back flow. You have a system with a flow & return but the stop valve is only in one leg. This should cut off all flow in the circuit, but there are always "other paths" where the water can back flow thro some rads so these will continue to warm up. It can be stopped if you want to install one way valves or angled tee's."

Not sure what you are trying to say with this CH and HW do not mix ... should have 2 tanks in the roof, one feeds the hot water and the other feeds the sealed loop in the cylinder which heats the hot water the only valve is a 3 way which would send heat either 2 the HW or CH/HW

A older system had a tank called a fortic (ok spelling might not be right) it used a air bubble to fill CH system ... but these tend to be long gone ... You would only have one roof tank

If rads are getting warm when only on HW the most likely problem is a stuck 3 way valve