Question about Cylinder Thermostats and My Old Boiler :)

Lizbetty

Morning everyone!

After the first month in our new (but old house), we have just had a bill from British Gas for both gas and electricity. £318!!! For a month! :eek::eek:

Granted we are on the standard tariff while we're waiting for the switch to go through, but still.

And so, I'm having yet another look at our set up.

We have an old Baxi boiler which has been serviced up to date by British Gas. It has a knob which is numbered 1-4. Our water is very, very hot and so I switched the knob to 2.5, as it was on 3.5. I'm not sure whether I'm doing right or wrong by turning that down, for two reasons...I'm concerned about the temperature of the water being too low to kill any bugs in the system, and also whether it will take more energy to warm the water up for the radiators if I turn that particular knob?

The tap water is still too hot to hold your hands under, mind you.

My other question is, is it possible to have a cylinder thermostat fitted with our current old set up? I'm wondering if we can regulate the temperature of the tap water separately to the water which fills the radiators, so that we can have the hot tap water at 60deg or whatever is the minimum to kill the bugs, and the water for the radiators set higher so that they warm up quickly (and presumably use less energy?)?

I feel that it's a daft question, but then again, I have asked three people and none of them know the answer either!

If anyone can help, I'd really appreciate it.

After the £318 gas bill, I'm even wondering if the pub up the road is tapping into our gas and electricity! I'm absolutely gutted.

My husband is thinking that we would be as well replacing the boiler for something more efficient but I'm not sure we'd claw back the outlay as the boiler might be efficient, but the house is a 1930's detached which we will never make as energy efficient as the new builds. Plus, we're brassic.

Thanks for any advice anyone might be able to offer,

Lucy

Johnandabby

Have you checked that there isn't a cylinder thermostat already installed, and possibly hidden behind an insulation jacket? If there isn't one already, then yes you should be able to get one fitted fairly easily, although you may need to install a new control valve for this to work and redo some wiring. I would do exactly what you have proposed, but be mindful that you may end up redoing the whole control system if it's been installed cheaply/wrong. Still worth doing, as you're likely to get the money back in less than a year in lower gas bills.

You don't (long term) want to use the boiler stat to control hot water temperature - while it shouldn't use more energy to heat the radiators, you may find it doesn't heat up enough on really cold days. 60 deg is what is recommended for cylinders to kill off bugs like legionella, but I run mine at 50 deg for 6 days and then heat it up to 60 deg for the 7th day - the bugs breed in stagnant and warm water, so if you are using the water regularly there is a much lower risk.

At the same time, have you checked the timings on the programmer, got TRVs installed and checked if you have a room thermostat? Always takes a bit of time to get used to a new house and how it is set up.

Priority should be to insulate the roof as much as you can, before replacing the boiler.

penrhyn

You can control the water temperature in you tank if you have a fully pumped system, which would have a two way motorised valve. If hot water is gravity fed then the answer is no, although it might be possible to fit a cyltrol valve.

macman

Basics first. Estimated or actual bill?
Are the opening and closing readings correct?
£££ bills tell us nothing-what matters is your kWh consumption on each fuel.
Post this info and proper advice can be given.
Your CH and DHW circuits should be entirely separate, what work this involves depends on your existing system, but usually it's achieved with a tank 'stat and a motorised 3 port valve.

Lizbetty

Thanks for your replies.

The estimated bill was for £600+! This is the bill after the reading, and so we know it's accurate (or as much as it can be). I'm still waiting for British Gas to send the paper copy so I can see which proportion is gas and which is electricity, etc. As soon as that comes through I will post the figures.

I did try and access the details online but as it's a sort of interim account it doesn't let me set up an online account. I'd ring them to get the usage info to post on here but our landline hasn't been installed yet and our mobile bills have been horrendous sorting this kind of thing out.

If I'm honest, I'm not totally au fait with this kind of thing and so I can tell you what I have learned so far about the set up we have.

We have the old style Baxi boiler, a Horstmann programmer and an analogue Danfoss thermostat (minus the numbers..they've been cleaned off). I will be replacing the thermostat as soon as we can afford to as per advice on here, and getting a decent digital one instead.

All of the radiators apart from the bathroom and en suite have trvs fitted, although we do have a few leaky ones..!! The hallway radiator where the thermostat is located also has a trv.

In the boiler cupboard, there is a Grundfoss pump which is apparently an expensive one - it's currently on setting II and is running at 24 watts when the heating is on. It was on the advice of the plumber that we changed the settings, I had it on auto but the ensuite radiator (which he'd come out to sort out as it was leaking/not getting warm) was cool and he said the pump might've needed to be on a higher setting, but we are to make sure we keep an eye on the overflow in case we have it on too high.

The plumber said that the fact the pump was showing a higher wattage after he changed the setting wasn't a reason to panic about cost. Before though, when it was on auto, it was on at around 9 watts. But I am wondering how much upping the setting will affect our bill?

I have replaced 80% of the lights with low energy/LED bulbs over the past three weeks as they were all full fat ones when we moved in (all the ones we use regularly are now low energy).

We plucked up courage to check the roof void last weekend. The roof is slate with no felt, but it has really thick lagging laid down.

The windows are double glazed but are definitely not that great - you can feel the cold when you put your hand to them. They're not ancient but certainly not as good as our previous ones (which were 17 years old!).

It's a 4 bed detached and so we're exposed all sides. Oh, and we have an awful powerflue fire which the wind absolutely howls through. We daren't switch it on because of the cost, and so I shoved some bubble wrap up me flue a few days ago to help with the draught! (Everyone knows I did this and we won't be switching it on, I put some bubble wrap over the control panel too as a reminder).

I hope that this information will help, I'm sorry if that's a ramble but I'm trying to think of all the things which may have contributed to the bill being so high.

We did have the heating on a bit over xmas, and now it's on twice a day for short periods. I'm really quite paranoid and keep turning the thermostat down (my husband keeps turning it back up because he says it cold) but not knowing the exact temperature on that is bothering me, too. We never went above 20degrees in our old house. I guess getting a new thermostat is quite a priority.

Thanks again for any advice you can offer, I really do appreciate it.

I'll go and have another read of your replies and make some notes

Lucy

Lizbetty

ps the hot water tank has been boxed in very oddly - my husband did take the wooden panel off as my finger went through a weird bubble in the artex in the room directly below where the tank is - I guess they've had a leak at some point and I wanted him to check it. He put the cylinder cover on a bit better than it was and he didn't spot a thermostat - I'll get him to check again when he has a mo (probably tomorrow now as he's working and the tank is in my 7 year old's bedroom so she'll be asleep when he gets back).

matelodave

You really need to check out all the pipe runs & controls (or get a proper heating engineer to do it for you) to find out what sort of system you've got and what if anything can be done with it.


Without knowing how your system is configured you will get a lot of advice based on what people think you've got rather than what you've really got and most of it will be wrong or irrelevant


If it's a fairly old system then you might have what's called a 4 pipe system where 4 pipes come out of the boiler, 2 for the central heating with a pump somewhere in the return pipe and two fat ones that heat the hot water cylinder using gravity circulation. This is the sort of system where the tank can get quite hot as it is heated virtually all of the time, just controlled by the boiler stat. All the room stat does is turn the pump on & off. The time switch just turns the boiler on & off and enables the pump to run. You can't have heating without hot water. It's not very efficient and not everso easy to control. It can be tweaked to fit a motorised valve & thermostat to the hot water circuit and to rewire the room stat to switch the boiler independently of the hot water as well although it might need a relay to do it or possibly another motorised valve.


Alternatively your system might have a motorised valve which diverts the hot water from the boiler to either the tank or the heating circuit, generally this is a two pipe system and all the water is pumped. Generally though this sort of system should have a thermostat on the hot water tank to control it (usually hidden in the lagging about a third of the way up from the bottom). You should also be able to find the motorised valve somewhere in the pipework.


As I said a decent heating engineer should be able to tell you what's possible and what's worthwhile. I've sorted out several 4 pipe systems and made them much more controllable without having to change boilers or doing much re-plumbing just by fitting motorised valves and putting suitable thermostats & timers in to control them

Lizbetty

Thanks, that is a good point. I didn't know whether what I'd described might be enough to ascertain what type of system it is, as I'm not up on them at all. There are certainly a lot of copper pipes and also a white plastic adapter box type of thing attached to one of them, I'm wondering whether that could be the motorised valve you mentioned.

I'm always hesitant to call out people for advice because of bad experiences in the past - although mostly it's lack of funds at the mo, I'm worried about someone recommending something we don't need because they know we don't know the ins and outs. I try and google to get as much info as I can and then I'm happy that I know enough not to get fleeced. I know not all tradesmen are like that, but a couple of bad experiences has made me wary. Also, I hate not knowing about things :rotfl: I always try to get to know about *everything* that breaks/goes wrong, which is why my head is usually quite a pickle and my laptop is red hot from googling.

We do have the bill, arrived quite promptly! The breakdown is as follows:

Gas debit £187.27 - 3547.62 kWh
2844.90KwH X 4.810p
702.72 x 4.64p

Electricity debit £131.11 - 903kWh
723kWh x 13.100p
180kWh x 12.590p

Again, I'm not sure if this is the exact info that you would need?

My mother did wonder if this is normal for this time of year, and we don't usually notice because it's spread over 12 months. It just seems *so* expensive though.

Thanks again for taking the time to help me out, all of your replies have been really useful.

C_Mababejive

Does the cylinder have spray on yellow foam lagging ? If yes,great. Even so, and if there is space,get an old quilt and wrap the cylinder in it. Get some cheap slip on foam pipe lagging and lag as much pipework as you can see in the cylinder cupboard/around the pump etc. Lag the hot water draw off for as far as you can access. If water is still hot and rads still hot,nip the boiler thermostat down a bit more.

matelodave

Have shufti here to see what the differing pipe arrangements look like. You can draw your own diagram to see what your system looks like
http://www.upperplumbers.co.uk/plumbing/Central_heating_system/central_heating_pipework.html

Lizbetty

C_Mababejive wrote: »

Does the cylinder have spray on yellow foam lagging ? If yes,great. Even so, and if there is space,get an old quilt and wrap the cylinder in it. Get some cheap slip on foam pipe lagging and lag as much pipework as you can see in the cylinder cupboard/around the pump etc. Lag the hot water draw off for as far as you can access. If water is still hot and rads still hot,nip the boiler thermostat down a bit more.

It's a very old cylinder and just has the red jacket on it. I never thought about lagging the pipework, thanks for the tip! :beer:

I am a little worried actually as I had noticed the ceiling artex in the room below where the hot water cylinder is housed has a bigger bubble which I didn't notice before, and so I'm thinking that might be new I'm now sure what will be going on, it could be a leaky pipe under the floorboards maybe. My daughter's radiator is around a foot away from the hot water cylinder, it looks fine and my husband said there were no leaks from the hot water cylinder which he could see. It's very odd. I even wondered whether the hot pipes might've made the artex bubble as the bubble I stuck my finger through was dry!

I shudder to think how that will pan out.. it's something we'll have to look into though.