Why can't I get hot water unless I put the heating on?

[bexta]

Hi, i've recently moved into a very old house. The heating system runs from a baxi boiler. The only way I can get hot water is to put the central heating on. On the control switch there are only 3 options: 1) off 2) timed and 3) constant. There is no option for water to be heated alone. Can anyone advise if this is normal or how I can fix it in very simple terms. Cheers!

[Tweed]

Sounds normal, but not ideal. I assume you have an oil fired boiler. You can plumb directly from the boiler to the coil on the cylinder, independently from the heating system, which would give you hot water without heating the radiators, but I think your system is plumbed such, that the coil on the cylinder acts just like a radiator to indirectly heat the water. If you have two pipes at the boiler than it's plumbed this way, if you have four it is plumbed the former way.

[pilotlight]

bexta, More info required. What type of boiler is it, is it wall mounted, floor standing, or situated behind the gas fire ? Also what model is it ?

[bexta]

Thanks both. I cant see any of the pipes to the boiler. Its a gas fired bolier and its behind the gas fire hidden in the wall. Its a back/baxi boiler. There is no thermostat on any wall, all I have is the main timer switch and the water tank in the bathroom.

[bexta]

I've just checked the manuals that I have, its a Baxi Bermuda 45/3 or 57/3 gas fired central heating unit and a Randall 103 time switch. Is that any use?

[feebal]

I had exactly the same problem when I moved into my house. I decided to rip out the old boiler (and all the tanks) and had a combi put in. When the plumber came to do the job he said I should have been able to have hot water separately using the emersion switch but that the switch or connection was faulty. The emersion switch was in a really random location, no where near the central heating controls, in a totally different room! I suggest you have a look around for a switch that doesn't appear to do anything... you might find it's your emersion switch.

[Tweed]

Don't you want to heat just the hot water to the taps, without heating the radiators, but using the gas boiler rather than using the electric emersion heater? Or am I mistaken?

[ann_h]

Do the radiators not each have a control tap? So you could just turn them all off or to minimum while you're saving up for any replacement/repair.

[turboped]

First you need a programmer that lets you control HW and CH seperately.

This is how it works. Programmer calls for HW this send feed to Cylinder stat, if water in tank is cold cyl stat is closed and feed goes to Motorised Valve, motor oin valve turns opening valve i.e. water flow to HW system and also make a switch sendind feed to pump and boiler.

CH sytem works same way, Programmer CH > Room Stat > CH Valve > Pump and Boiler.

There are many varyations to this theme but I found this easiest to explain.

[turboped]

Sorry about the typos.

[bexta]

Ok, where shall I start. There is a switch next to the hot water tank in the airing cupboard but that is already on, from what I can see it does nothing, could this be my emersion switch?

Yes I would rather use the gas boiler to heat the water than the electric but i'll settle for any way of getting hot water at the moment!

I thought about turning all of the radiators off, but all of the taps are welded on because they are so old. I thought about turning the thermostat right down too but I don't appear to have one!

Ok, by programmer do you mean the control switch that turns the heating/water on? Would this just be a case of replacing it with a new one and changing the wiring?

[turboped]

There may an immersion heater switch by the tank which may have a flex leading from it to a something that looks a bit like a cup stuck to the side or on top of the tank. Inside this cup is the Immersion heater and immersion heater stat. Or you may not have one.

Sounds like you need an overhall of your system, I'm not a plumber but I think there will be some pipework involved and suitable electrics depending on what type of system you plump for.

What area are you?

[bexta]

Ok, when I look at that switch, the wire leading to it just appears to go down past the water tank and maybe through the floorboards, there is no other wires coming from it.

Thats what I thinking but I thought I'd see if there was just a simple fault with it 1st. I think its just plunmbed and wired like that because its old and basic.

I live about 30 minutes from Birmingham.

[turboped]

It sounds like you may have an immersion heater circuit and switch but no element in the tank or at least not connected up. You might need to go with anna_h suggestion that you try to turn the rads of at each one until you find a solution.

Sorry.

[pilotlight]

bexta, To go back to your original question, yes ,this system is normal -- or, rather, it was years ago !

From the info now given, I would assume that your system is " gravity hot water - pumped heating ". The switch that you have found near the cylinder could be a switch that controls the pump ( you say it is now in the "on" position, this is why your heating comes on when the Randall 103 brings your boiler on.)

Try bringing the boiler on, then switch off the switch near the cylinder, if my assumption is correct, you will then have "hot water only". The temperature of the water will probably depend on the boiler thermostat setting ( behind the removable paneI, under the gas fire ). If my assumption is not correct, I suggest you aquire a reputable local heating engineer to inspect the system.

Hope this helps.

[bexta]

Thanks for all of your answers. Are you sure that the switch next to the tank is not for anything else? There is a switch next to the gas fire which I switched off when I first moved in and the pilot light went out, oops!

I have at the moment managed to turn all of the radiaotrs down but they wont go off completely.