Turning Hot Water on Turns Central Heating On?

anotheruser

Hi all

I have a RWB9 (Siemens) control unit and set up the central heating with certain hours of operation. It asked me if I wanted to copy this to the hot water. I said yes.

I left it with the Hot Water as "on" and the Central Heating as "off". So I thought this would mean it would leave the CH off and heat the tank to give me hot water.

However a half an hour or so later, I noticed the radiators were all boiling hot. We had hot water as well, but that's not what I want as the house is warm enough without CH.

Have I missed something obvious or is it a call to an engineer?

Thank you for your candor.

Hoploz

You could try turning the thermostat down.

If you have a faulty valve switch it can mean that when it's meant to feed only the hot water it feeds both, which looks like it is ignoring the timer clock. I think if the heating is going on by this fault, it over-rides the thermostat.

m.colak

Check your inline valves as the previous person said you might find that one is clicked to manual open ( Central heating ) rather than auto. They look like metal boxes attached to your pipe work which should have a sliding lever arm at one end.

anotheruser

I'll have to take some photos and get back to you as I have no idea where to look

m.colak

Usually in an airing cupboard, near your large water cylinder, usually underneath.

anotheruser

Here we go:

On/Off button and thermostat knob on boiler:

It says I should turn the knob round to the desired level, but how do I know what that should be?

Boiler Control Panel:


Temperature Control on Tank:


Red Box in tank:

Can anyone tell me what this is? It gets very hot when the system is running.
It also has a I, II and III, of which III is currently selected.

Blue box in tank:

It says "Mid Position Actuator" on it.

Layout of tank area:



The blue box is switched to W. There's an H and M. I guess the H is Heating, W for Water and M for Manual? The black switch on the side can move but I haven't switched it yet.

Also, as a side note, the thermostat is set to 0. I guess if I set the control panel to "auto" then it'll pay attention to the thermostat? When I've been testing it, I've set it to "on" so it seems to ignore the desired temperature and be on full blast.

Thanks for the help ��

Ectophile

The roundish red thing is the pump. They do get quite hot.

The blue thing looks like a diverter valve. It should be electrically operated by the heating controls. Perhaps it's stuck, so water is going both ways.

Le_Kirk

The Mid-Position Actuator or diverter valve (blue thing) is H(eating) W(ater) and M(id position). The black sticky out bit on the diverter valve is the manual operating lever. What happens to the diverter valve indicator when you turn on the hot water? Also check the pipes by feeling them. The flow from the boiler will feed into the Diverter Valve (Mid-Position actuator) and one pipe will go off to the hot water tank and one to the heating system. If all three pipes are same temperature (when your central heating demand is OFF) then the valve may be stuck. Try turning on the central heating demand, turn water off and see what happens to diverter valve indicator. Then turn off central heating demand and turn on water, valve should spring return to water position.

anotheruser

I tried just heating but the switch didn't change position, so I guess it is stuck?
Is this a plumber job - my skills are less than 5 out of 100 in this area :P

Le_Kirk

Not necessarily a plumbing job (no soldering skills required) but someone with central heating/boiler skills knowledge.

anotheruser

Well, I gave the little black leaver a pull on the end, and now the black pointer on the side is pointing to H.

Gonna give the boiler another try tomorrow morning and see what happens. I'm hoping it'll switch back as I'd rather have W and H rather than just W