Mystery always on towel rails

Jeepers_Creepers

oniongirl said:

I think, though it's hard to be 100% certain, that the only whirr I hear is from the central heating valve. Fingers crossed it's an easy job. Of course our fella is busy on a "proper" job for the next week, so for now I'll just be turning the temperature of the water up and down.

A straight-forward job for a plumber. ~£80 for the whole valve, and around an hour to do (as long as nothing goes wrong...)

Or, around £50 for just the head part, and a half-hour to swap.

If you go for the latter option, then I'd suggest buying the whole part, and keep the valve body for future replacement, for whenever the system will need draining for, say, another valve. Keep it in that cupboard so's you don't lose it...

When the plumber removes the 'head', he'll be able to tell if the valve part is working ok - no leaks, turns smoothly from one position to the other, with a nice muted 'clunk' when it 'shuts'.

oniongirl

Jeepers_Creepers said:

A straight-forward job for a plumber. ~£80 for the whole valve, and around an hour to do (as long as nothing goes wrong...)

An hour of chatting, half an hour of tea drinking...  We love our fella, I'm only kidding. He gave us and installed a new board for our old Potterton boiler for our wedding present a few years back. 

ComicGeek

Even if the HW valve is faulty, I don't see that it would trigger a call for heat when the programmer is off. I still think it's worth getting the controls wiring reviewed. 

Jeepers_Creepers

ComicGeek said:

Even if the HW valve is faulty, I don't see that it would trigger a call for heat when the programmer is off. I still think it's worth getting the controls wiring reviewed. 

It will. The 2-porters have a permanent live, and it's this that's switched through the microswitch to turn on the boiler. All the programmer-and-thermostat does is to operate the motor.

You can demonstrate this by manually pushing the lever all the way across to open the valve when it's programmed to be 'off' - it'll trip the m/s and turn on the boiler.

Snuggles

Yes, I had this problem - boiler continually firing when there was no demand for either hot water or heating. It was a faulty valve.

homersimpson246

As above, the way heating systems work is that the programmer opens the valve and the valve opening turns on he boiler.  The boiler running controls the pump.

If the valve sticks open then the boiler will fire even if the programmer is off.

Snuggles

oniongirl said:

P.S. if you see any hint of an immersion heater in there let me know  I can see a white cable coming from what I'm presuming is the thermostat for the hot water, but it goes in to the serious business looking grey box that the programmable thingy is seated on that all the other wires to in to 

The white cylindrical thing sticking out of the side of the tank looks like the immersion heater. I have an unvented cylinder and it has exactly the same cylindrical thing - mine actually has "Immersion" printed on it. Mine has a cable coming out of it which goes to a switch on the wall next to the cylinder, which is (obviously) the on/off switch for the immersion. It's come in very handy a few times when the boiler has broken down.

That switch on the wall on the left above the programmer - is that for the boiler, or could it be the switch for the immersion?

oniongirl

Snuggles said:

oniongirl said:

P.S. if you see any hint of an immersion heater in there let me know  I can see a white cable coming from what I'm presuming is the thermostat for the hot water, but it goes in to the serious business looking grey box that the programmable thingy is seated on that all the other wires to in to 

The white cylindrical thing sticking out of the side of the tank looks like the immersion heater. I have an unvented cylinder and it has exactly the same cylindrical thing - mine actually has "Immersion" printed on it. Mine has a cable coming out of it which goes to a switch on the wall next to the cylinder, which is (obviously) the on/off switch for the immersion. It's come in very handy a few times when the boiler has broken down.

That switch on the wall on the left above the programmer - is that for the boiler, or could it be the switch for the immersion?

It's the switch for the boiler. It looks like the previous owners must have removed (or damaged) the cable for the immersion at some point and removed it. 

If my heating man ever turns up to save me from turning the temperature on the hot water up and down all the time to make it stop, I'll ask him about it, as I agree - could be useful in a boiler emergency.

oniongirl

Update: I should not have twiddled the knobs on the towel rail. One of the valves is now leaking. And still no news from my heating fella except for a "later in the week" message on Monday. 

Could it be that the valve I twiddled wasn't to control the heat? Which way should I turn it if I have accidentally loosened something? Or is it more likely that no one ever touched the valve and it's just broken.

Things have now escalated. The heating appears to want to stay on all the time, too. I shouldn't have jiggled its valve to compare with the HW.

What is it with valves? Seems you just have to look at them the wrong way.

fezster

Jeepers_Creepers said:

ComicGeek said:

Even if the HW valve is faulty, I don't see that it would trigger a call for heat when the programmer is off. I still think it's worth getting the controls wiring reviewed. 

It will. The 2-porters have a permanent live, and it's this that's switched through the microswitch to turn on the boiler. All the programmer-and-thermostat does is to operate the motor.

You can demonstrate this by manually pushing the lever all the way across to open the valve when it's programmed to be 'off' - it'll trip the m/s and turn on the boiler.

Not the case on honeywell 2 port valves. The manual lever wont go far enough to operate the microswitch. Though there may be different variants.

However, I agree with you that the microswitch is probably stuck, causing the boiler to fire even with the programmer off.