Only heating hotwater on old boiler

missmac

I've just moved into a new house and have an old glow worm boiler which has
a hotwater tank (covered with a red insultating jacket) in the bathroom. To heat the hotwater, I've had to turn on the central heating for 2 hours even though the weather is now turn mild. Is there anyway that I can heat the water instead of both water and heating - there is a switch with a red light outside the bathroom which I've just discovered although it doesn't appear to heat the water independantly.

Apologies if this sounds a really basic/stupid question but I'm house-sitting for a month and the owner is trekking in the andes and not contactable.

Many Thanks:-)

ormus

the boiler should have a switch to select, heat water only, ch only, or both.

the electric switch with the red light is the immersion heater, used during summer. maybe its a failed element?

bockster

there are so many variables here depending on the type of system you have there.
to keep things simple at this stage, i would go with double checking the 'switch with the red light outside the bathroom'. this is most likely for an immersion heater if indeed it is fitted. (electrically operated heating element fitted into the hot water tank).
leave the switch on for a few hours when next the hot water is cold to see if this has any effect.
other than this i would need more info on the controls for the heating system to be of any help.
others may follow with other advice.

EliteHeat

Older systems sometimes only allow you to have hot water or hot water plus central heating. It is never the other way around, therefore you have a problem.

You almost certainly have a fully pumped system with a 3-port motorised valve. You problem is likely to be either the motorised valve, the cylinder thermostat or the programmer itself.

In order to let you know which it is, you need to describe your system in much more detail; programmer manufactirer and model, system controls etc

missmac

Thank you so much for all your helpful replies - much appreciated.

My friend said before she left that the boiler was about over 15/20 years old but serviced every year and the parts are still easy to find. It has a thermostat and separate programmer (I think - its directly below the boiler and is basically a dial where I can adjust the time and how long I can put the heating/hotwater on for). On the programmer it says Glow worm master mind and on the boiler itself it says Glow warm space-saver - if thats any help.

Once again, thanks again for the replies:-)

EliteHeat

In the airing cupboard look for a silver box with either two or three copper pipes going to / from it - this (these) are the motorised valves. There will be an actuator at one end, this can be operated manually and latched to keep it open.

If you have a three-port valve then and operate the valve manually, this will provide heating and hot water. If you have a two-port valve then this should allow heating independantly of hot water.

Either way, it is a temporary fix and needs to be fixed.

roswell

Our diverter valve went on our combi tonight, it must be the season, good news is we can get luke warm water while the heating is on only and none when the heating is off. Sounds similar to your problem.

EliteHeat

roswell wrote: »

Our diverter valve went on our combi tonight, it must be the season, good news is we can get luke warm water while the heating is on only and none when the heating is off. Sounds similar to your problem.

Not exactly, they do not have a combination boiler, but other than that you're right.

missmac

Many thanks for the advice EliteHeat. I'm at work at the mo but as soon as I get home, I'll check whether I have 2 or 3 valves and do that temporary fix. It will be nice not to be sweating buckets just to have a shower but I suppose good for weigh loss!

Can I just ask, what is the purpose of the switch with the red light, outside the bathroom? Sorry if that sounds really basic but I live in a flat with a combi boiler and its already set to the right temp and supplies constant water.

Thanks again

thescouselander

I thought that old heating systems relied on convection to get the hot water from the boiler to the hot water tank (i.e. not fully pumped) and thats why it takes ages to heat a tank of water. Also if this is the case there might not be a motorised valve.