Plumbing help needed

shodan · 02-05-2007, 8:37 PM

Any plumbers / central heating / home hot water / master DIY'er experts out there?

I don't know a great deal about this stuff so I'll just give some details and the symptoms as know them...

The house has a water tank / immersion heater thing (big cylinder thing in a little cupboard) which as far as I can tell handles the hot water for the taps.
there is also a combi boiler which seems to only jump into life when the central heating is on. Its for that reason that believe the immersion heater does the hot water.

Anyways due to the hot weather the central heating has been turned completely off from the timer. Well I guess more acurately, the timer is set to not come on at all so the heating doesn't come on.

But since that, I've not really had an hot water from the taps. Its not freezing cold, as cold as the cold tap water but its not warm and doesn't make for nice showers or shaving. It seems that sometimes the water is hot enough, but its certainly not a case of turn the tap (or shower) on and voila, hot water. It can take ten minutes for the water to warm up sufficiently.

From the immersion tank was a two way lever, one position is central heating, the opposite is hot water. The lever was set to the middle but now I've moved it to Hot Water, but it doesn't seem to have changed anything....

From the plumbing from the cylinder is a electric water pump which I think feeds to the combi boiler.

Thanks in advance folks!!!

metropolis · 02-05-2007, 8:43 PM

are you sure its a combi boiler ? what is the make and model

**johnscarlet** · 02-05-2007, 8:43 PM

Combi boilers don't normally have a tank , the idea is that you heat water while you use it . What make and model is it ?

In the meantime , does the tank have a cable coming from it , somewhere near the top ? if so you could possibly follow it to a switch , which will turn on the electric heating element , But only have it on for as long as necessary , your leccy bill will rocket . Its like boiling a kettle , without the auto turn off

John

shodan · 02-05-2007, 9:17 PM

Yeah it is a bit odd! There is a fused switch in the airing cupboard which has been on for as long as I've lived here (since 21st december last year). There is one cable from it, which goes to the central heating timer. Another two cables from the timer to the water pump and the combi boiler. There doesn't appear to be any cables from the cylinder.

Must re-iterate the point tha is confusing me most. There was no problem till I stopped using the central heating. Apart from I'm not using that, nothing else has changed or been changed (to my knowledge!).

njp · 02-05-2007, 9:33 PM

You've presented a lot of conflicting information. If it's a combi-boiler, you wouldn't need a hot water tank. And why does the water warm up after ten minutes?

If you hadn't said those things, I would have assumed that you have a conventional boiler and the thing with a two way lever is a mid position valve (diverter). This is a motorised valve to control the flow of hot water from the boiler to either the radiators or the hot water cylinder, or both, depending on which system is calling for heat. That in turn depends on thermostats (is there one on the cylinder?) and on the timer controls. Does your controller have a seperate setting for hot water?

In summary: check cylinder thermostat and timer controls first. If they are in order, you may have a faulty diverter valve.

blitzed · 02-05-2007, 9:43 PM

to me it sound like you have an old servo warm system.
was the lever thing a manual control (looks like a round cylindrical thing with lever sticking out sometimes has red and yellow on it).?

shodan · 02-05-2007, 9:52 PM

Quote:

Originally Posted by blitzed

was the lever thing a manual control (looks like a round cylindrical thing with lever sticking out sometimes has red and yellow on it).?

yep, thats the one, exactly as you've described!

njp, I know there is a lot of contradictions there and I know I should have one or the other, would normally by the combi boiler. In the future I'm looking at getting rid of the cylinder to knock the cupboard out as it in the kitchen, taking up a lot of room! Could you explain to me how to check the cylinder thermostat please?

njp · 02-05-2007, 9:55 PM

Quote:

Originally Posted by shodan

njp, I know there is a lot of contradictions there and I know I should have one or the other, would normally by the combi boiler. In the future I'm looking at getting rid of the cylinder to knock the cupboard out as it in the kitchen, taking up a lot of room! Could you explain to me how to check the cylinder thermostat please?

I think I'll defer to blitzed's greater knowledge. Manual 3 port valves are beyond my experience!

blitzed · 02-05-2007, 9:55 PM

have u tried moving the lever to hot water only and turning the timer on?
this will divert hot water from boiler flow and return circuit to the h/w cylinder only
ed

shodan · 02-05-2007, 10:22 PM

I've had a fight with it and managed to move it over to hot water only (it was stuck though, not been moved for ages).

When you say turn the timer on do you mean activate the central heating for a while? Its cold upstairs so I could do that now for 30 mins or so. I'm not sure I understand your last sentence, but then I don't understand how a lot of thins wrk, I'm just happy when they do!

**IronGiant** · 02-05-2007, 10:32 PM

Quote:

Originally Posted by blitzed

to me it sound like you have an old servo warm system.
was the lever thing a manual control (looks like a round cylindrical thing with lever sticking out sometimes has red and yellow on it).?

Spot on that sounds just like what he's got, we had one when we moved into our last house 17 years ago and it didn't work properly then, exactly the same symptoms Shodan has. I stripped out all the Servowarm manual rubbish (that was much touted as being reliable

) and put in a proper electrically controlled valve and thermostat for the house and cylinder. It was still working fine when we left 10 years later.

It sounds to me as if someone who thought they knew what they were doing has fiddled with it to try and improve/mend it without knowing what they were doing. As such you may have inherited a nightmare Shodan. Can you post any photos of wiring etc?

Dave

shodan · 02-05-2007, 10:35 PM

what wiring? There really isn't any! the only wires in the cupboard are the one's I've mentioned above. Got me worried now in case there is other wires that I can't see or that are missing!!!!!

**IronGiant** · 02-05-2007, 10:38 PM

Quote:

Originally Posted by shodan

I've had a fight with it and managed to move it over to hot water only (it was stuck though, not been moved for ages).

When you say turn the timer on do you mean activate the central heating for a while? Its cold upstairs so I could do that now for 30 mins or so. I'm not sure I understand your last sentence, but then I don't understand how a lot of thins wrk, I'm just happy when they do!

If you cranked it over to hot water you shouldn't heat any radiators at all, and if you do it's broke

Yes, turn the boiler on (manual overide the timer?) and just see if the pump vibrates at all and if any pipes in the airing cupboard get warm.

Dave

shodan · 02-05-2007, 10:42 PM

will do, stand by!

shodan · 02-05-2007, 10:51 PM

ok, the valve selector is set to hot water. the central heating timer is set to 24hours. When I did this, I heard the combi burst into life. The pipes FROM the cylinder are hot to the touch, to and from the valve selector are hot too. Hot water from the tap is warmer than it was, but not hot and still not shower tempreture. Do you think it'll get hotter if I give it some time? Can the system be left in this configuration?

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