Conventional boiler confusion!

Hello all.

Today i moved from a flat to a house.

I've always used combi boilers in my flat and in my mum's before that.

In my new house the boiler is heating only and there is a hot water tank in a cupboard with foam around it and a temperature sort of thing stuck to the outside of the tank.

I genuinely have no idea about this at all, being so used to combi boiler! I also have no idea how to work the crazy thermostat which controls it all, my old combi boiler just had a mechanical timer for the heating.

Can anyone please give me any insight into how to use hot water with this type of system? I haven't tried to use any yet. Could I run a full bath? Is it more expensive to run? Should I see about replacing it with combi.

Sorry for all the questions but I am completely lost with it all.

Many thanks for any replies!!

Comments

  • ValiantSon
    ValiantSon Posts: 2,586 Forumite
    It is most likely (unless you have an old and cheap installation) that the controls allow you to set independent times for hot water and heating. If you set them to heat the water each day for a specified period of time, it will fill the hot water tank and you will be able to draw hot water as required (depending on the quality of the insulation on the tank you can expect this to remain at a reasonable temperature for 20-24 hours).

    The thermostat is just a control for the central heating. You set it to a specified temperature and it switches the heating on and off accordingly (during the times "on" periods) to keep the house heated to around that temperature. I suspect that you are actually talking about the controls. Each control system works differently. Identify what controls you have and then google them for an instruction manual, if you don't have one.

    Assuming that you heat sufficient water then yes, you can run a bath.

    There is no particularly good reason to replace with a combi boiler.
  • System
    System Posts: 178,093 Community Admin
    Photogenic Name Dropper First Post
    Hello all.

    Today i moved from a flat to a house.

    I've always used combi boilers in my flat and in my mum's before that.

    In my new house the boiler is heating only and there is a hot water tank in a cupboard with foam around it and a temperature sort of thing stuck to the outside of the tank.

    I genuinely have no idea about this at all, being so used to combi boiler! I also have no idea how to work the crazy thermostat which controls it all, my old combi boiler just had a mechanical timer for the heating.

    Can anyone please give me any insight into how to use hot water with this type of system? I haven't tried to use any yet. Could I run a full bath? Is it more expensive to run? Should I see about replacing it with combi.

    Sorry for all the questions but I am completely lost with it all.

    Many thanks for any replies!!

    Heat only or system boilers are usually the norm for larger properties. In both cases, the boiler just produces heat. Two or more motorised valves open and close to allow the heated flow to pass around the radiators; the coil inside the cylinder, or both. The thermostat controls the CH zone valve and an internal cylinder thermostat controls the zone valve to the cylinder. My property is equipped with a 250 Litre unvented cylinder which is timed to come on in the period 5.30 to 6.30 am each day. In truth, re-heating the cylinder takes about 45 minutes and, for example, yesterday the re-heating used about 7kWhs of gas. We have hot water available throughout the day - enough to run 5 baths.

    Converting a heat only boiler to a combi has its attractions - but cost is not one of them. All new combi boilers now have to comply with the new Boiler Plus 2018 regulations. Moreover, you cannot just change boiler types without changing the piping; removing the cylinder etc. In most domestic situations, a heat to combi boiler change only makes economic sense when both the boiler and the HW cylinder need to be replaced.
  • Thank you valiantson and Hengus. Guess it will just take a bit of getting used to and working things out.

    When should u heat the tank? It's not even a big house only 2 bed 1 bath. Haha.
  • System
    System Posts: 178,093 Community Admin
    Photogenic Name Dropper First Post
    Thank you valiantson and Hengus. Guess it will just take a bit of getting used to and working things out.

    When should u heat the tank? It's not even a big house only 2 bed 1 bath. Haha.

    It doesn’t really matter from a cost point of view. We have a hot water priority system so it makes sense to heat the cylinder when there is no heating demand. ON times depend on your usage pattern. When we had children at home, we had cylinder ON times from 6.30 to 9am and again at 4pm to 8pm. The timings do not mean that the cylinder is being heated constantly. HW heating will stop once the cylinder reaches the temperature set on the cylinder thermostat.
  • ed1178
    ed1178 Posts: 19 Forumite
    It is important to ensure that the full tank is heated to at least 60 degrees centigrade once per day or at least every couple of days. This is because legionella bacteria can rapidly multiply in water that is just warm. In a domestic situation you don't need to worry too much about this, but as some are in the habit of only barely heating enough water as and when they think they might need it it's worth a mention!

    In a small, one person property with gas water heating the cost of water heating will be a small proportion of your bill, regardless of the type of system. Probably less than £100 per year. You should therefore not worry too much about timing your water heating to exactly match your demand. As someone else pointed out, the tank will stay hot for hours anyway.

    The sensible thing to consider when setting your water heating time, is what time of day do you take your shower / baths? If it's first thing in the morning, set your water heating to come on two hours before you get up. It won't take that long to heat the tank, but by giving it plenty of time you will ensure the whole tank is thoroughly heated and sterilised. You then have your shower or bath while the timer is off, cooling the tank a little which will reduce the already low heat losses through the day while you are at work. You might want a shower or bath in the evening too, so consider a second heating period in the early evening. You might get away with one heating period per day, depending on the size of your tank and usage.

    you will probably need to experiment a bit with the times, but don't be tempted to scrimp too much for the reason stated above. Once the tank is properly hot, the boiler will switch off anyway, and the tank won't loose much heat while no use is taking place. If you really want to save money, take shorter showers and watch your other hot water usage, don't cut back on the temperature of the tank.
  • ed1178
    ed1178 Posts: 19 Forumite
    Further to the above- tanks are often fitted with an electric immersion heater as back up. These can be accidentally left on- sometimes for months- and will massively rack up your electricity bill!

    As you are using (much cheaper) gas water heating, take a minute to check that any immersion heater fitted to your tank is switched off. If you have an immersion heater it will be fairly obvious- a metal or plastic dome about the size of a teacup will be poking out of the top or possibly the side of the tank. It will have a wire running to it, from a switch often inside or just outside the tank cupboard, but sometimes in the kitchen or on the landing. If you have an immersion heater but can't find a switch and are unsure if it's on or not, wait until you have run off a lot of hot water (for a bath for example) and with the boiler switched off listen carefully to the cylinder. If the heater is operating you will hear a faint rumbling noise a bit like a quiet electric kettle.
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