CH problems

[st.john]

Hi, please help,
So, we recently bought a house, Essex, UK (detached bungalow about 100 m2, 1950-1960 era) in September, we have done some renovation, new flooring(laminate), new kitchen, new bathroom, changed couple windows from single to double glazing, changed one radiator in bathroom to towel rail.
All this time thermostat was set up for 18 degrees, like I said nobody lived in a house, just tradesmen and myself recently used to come in evenings to do the job, we received gas bill for nearly £700!!! (FOR WHAT???!!!)


The new central heating system was installed in 2019.11 new radiators, new pipes, and new boiler(there are paperwork for proofs etc.) Previous owner was very proud about that and told me he was boiling in the house (obviously he could lie)...
Last week we moved in, and then.....

1. The house barely reaches 18 degrees in any room, even the heating is constantly on. Thermostat is "HIVE" remote, we tried in every room it doesn't matter where it stays everywhere shows roughly the same.
2. The radiators have TRV all set on max, the flow from boiler 65C (tried and 60C - the same), rads get hot but room still very cold, tried heating all day long, no success. 1 rad in hall don't have TRV.
3. Insulation on loft 200mm, partly boarded. Double-glazed windows in every room (quite old).
4. All radiators take very long to preheat (except towel rail, I think it's 1st in line). And most of them very hot on top and warm on bottom.
5. All radiators are "designer" modern ones. Some vertical single, some doubles but horizontal. By the way, they all 5 years old but all of them rusted on the bottom and paint flicking on all of them.(this might be important detail.)
6. Smart meter shows that we use about 6–7 kWh in half an hour, then about 3 kWh and then 0, and then cycle again. 10Kwh every 1.5 hours... it's been 2000kwh for October, more that 3000kwh for November, and more that 3000kwh for December, I can't believe that's normal. In previous house we used 25 kWh a day, and 1000kwh on very cold month.
7. Boiler - Worcester Greenstar 32CDi Compact. Service have been done in September - came as all OK.
8. I've checked on boiler's settings, and it shows that return is only 5C lower than flow. So in my case, flow 65C return 60C.

Please help where I should start from to reduce bill and get house warm.

 

[Stuckinarut]

You might want to start with balancing, as you’re flow and return should ideally have a 20 degree difference. I would also check or have checked for any bypass failure and the diverter/motorised valve(s).

 

[Old Salt]

I have a bungalow (semi) built in about the same period, double glazed, 300 mm loft insulation, 8 standard radiators plus an under plinth heater and use gas for heating and hot water, combi boiler.

My place is warm with further capacity to up the trv settings etc. normally about 21 degrees and during November we used 995 kwh and December was about 1200 kwh.

 

[Justin Passing]

CHeck some radiator sizes against charts for similar types, do the calculations, see if they're big enough.
Then see if they add up to more than 24kW, if so your boiler's too small (unlikely).
If it's all calculated for a 20°C rise over outside, and outside is -3°, then it's working as designed.
The boiler obviously should go up to 82 on the flow. I know nothing of Hive thermostats so....


You DO NOT balance a system using the temperature knob on a trv, you use the lockshield valve the other end. (Unless you use the adjustment few know about inside the head of a Drayton TRV4). The rads nearest the boiler should be barely open, barely an 1/8th of a turn on the lockshield. Otherwise the boiler goes through the nearest rad , staright back to the boiler, which turns itself off because the water's hot. If that were entirely the case then farthest rads wouldn't be hot, which you say they are.
The return CAN be only only 5° under, your rads will just be emitting more heat, but it doesn't sound right. Feel the rads centre bottom edge. Are they all really that hot??
It would be more efficient if the return were cooler, but we're in the weeds now, something else is wrong.

 

[JohnD]

"detached bungalow about 100 m2, 1950-1960 era"

It would have had poor insulation when new

You have 200mm loft insulation now?

Does it have CWI?

I don't understand why you had the heating set to 18C when it was unoccupied. What dates did the £700 bill span?

Is there a hot water cylinder? What colour?

You say the radiators are hot at the top and warm at the bottom, but boiler return is 60C
The water from the bottom of the radiators returns to the boiler. Therefore it is short-circuiting somewhere. Is one of your radiators fully hot? Turn it off. Do the others heat up?

 

[fixitflav]

we received gas bill for nearly £700!!! (FOR WHAT???!!!)

Assuming that's for the time since you moved in, about 4 months, autumn/winter, that might not be too far out. Did you read the meter when you moved in, to make sure you're not billed for gas before then?

 

[Stuart981]

I have no idea about the bills but If the heating system was working OK for the previous owner then maybe he was operating the boiler in non-condensing mode.

 

[st.john]

Thanks for replies, but none of them seems to have any answers. Maybe somebody have more suggestions.

What's have been done so far:
1. Supplier changed gas meter because I couldn't see readings myself, only smart readings went to British gas, and then I could check through app.
2. Added Insulation on the loft by another 200mm.
3. We put clear film over a few of the windows.
4. Added curtains everywhere where the windows and doors are.
5. Boiler's filter have been cleaned.
6. turned off few rads, so now only 6 are on.
7. Balanced radiators (all rads had lock shields opened full, so i reduced it drastically, starting with 1st one just nib and slightly increasing every one, till last one fully open)

We keep constantly 18 degrees on manual thermostat mode, not increasing not decreasing temp, day and night. Since gas meter have been changed, I'm checking every 24hrs the readings. It's been roughly the same consumption every day, no matter is it colder or warmer outside.. 8m3. or 90kWh per day. Obviously shower and hot water have been used, but not very often as we're using dishwasher.(it's to much, i asked loads of my friends to check their consumptions, and looks like they only use 3-4 m3 a day or 34-45kWh a day.(mine is double to that). Yesterday was quite warm and sunny day (at least till afternoon), but for some reason my usage increased to 10m3 which is 113.6kWh. Out of blue moon. Nothing differently have been done, thermostat on 18 degrees, 3 people been all day at home (assuming it should be warmer), missus have been cooking more than usually (electric) (the rooms should be hotter from that not colder), so the usage of gas should be lower, but looks like it's opposite way.
The house is still cold, and 18 degrees not enough, I would rather increase at least to 20 as before we constantly had it on 21 in previous house, but paid peanuts compare to this one.
So my question is can it be an issue with boiler??? One time I've tried to increase temperature and watch the boiler's actions, the boiler started heating up, but it took very long time until it reached 65 flow temperature, it's been stuck to 45 for few minutes, the radiators have been mild, then suddenly started heating up, but like I said it took some time about 4-5 minutes to kick in. Also, there is British Gas Boiler IQ thing (CL01)added to boiler, previous owner had subscription, we don't. Can this thing regulate something without my knowledge? Or there are some settings in the boiler itself, i can only increase decrease flow temp and hot water temp, everything else most probably require password and etc.

 

[Harry Bloomfield]

8m3. or 90kWh per day.

This past week, ending this morning, we used 54Kwh per day, 18C most of the day - mitigated by using a living room gas fire, 10am to 10pm, then a definite minimum of 14C 10pm to 10amp. Double gas oven, gas hob - used daily. 9 rads, in a 3 bed semi.

 

[st.john]

This past week, ending this morning, we used 54Kwh per day, 18C most of the day - mitigated by using a living room gas fire, 10am to 10pm, then a definite minimum of 14C 10pm to 10amp. Double gas oven, gas hob - used daily. 9 rads, in a 3 bed semi.

That's what all average people use..

I found that boiler was on preheat mode, now I turned it off, will check if that improve something, which I doubt.

 

[ericmark]

I moved in with late mother around 2017, and found nothing set with the central heating. So started to read on how to set up. Sounded great, but how one measures the input and output of radiators and set it to 16ºC is something else.

However, we found the TRV heads really helped, we were using Energenie which show target and current I closed the lock shield completely and waited until radiator cold, then opened 1/4 turn at a time, until one pipe got slightly warm. Then if current exceeds target, closed a small amount, and slowly got each lock shield set.

The whole idea is for the boiler to be analogue controlled, so the TRV is king. The wall thermostat should take a "demand for heat" as long as under 22ºC, so the wall thermostat needs to be in a room kept cool. The whole idea of the wall thermostat is to stop the boiler cycling once the house is warm enough, control is with the TRV heads.

If the boiler is switched on/off repeatedly, it will not run efficiently, it should turn up and down slowly, to match demand, as to not heating the house, likely the way set up, hot water is returning to the boiler in error, and so turning down the boiler output, once lock shield valves are set, it will likely work far better.

 

[Murdochcat]

Take readings once a week and that’ll give you an idea of usage

As for the £700 bill - did this use actual readings or estimates? Is the account in debit or credit?

Setting a room stat at 18 degrees when you aren’t living in a house is dumb to say the least. 10 degrees I could understand

 

[st.john]

Take readings once a week and that’ll give you an idea of usage

As for the £700 bill - did this use actual readings or estimates? Is the account in debit or credit?

Setting a room stat at 18 degrees when you aren’t living in a house is dumb to say the least. 10 degrees I could understand

For the last two weeks I'm taking readings every day at the same time, The bills are not estimates because it's smart meter and actual readings sent to British Gas. Yes, maybe I should leave it on 10, but we have done some renovations, and myself and some tradespeople everyday used to come and work there, so I prefer a warmer area to work. Like I said, in my old house, (almost the same size) I used to use three - four times less energy (in kWh) with higher temperature. I thought it will be roughly the same usage so for me, it's not a problem, I can afford that, but when I received a bill 4 times bigger I was shocked, that's when I started investigating. I'm still thinking it's something to do with boiler, or rads.

 

[st.john]

Another couple weeks without luck, we are monitoring the gas consumption every 24hrs and everyday get almost identical result. 8m3. It's definitely very strange because no matter, or we leave the boiler on all day long, or we leave the boiler off for half a day and using it only in evening, have almost the same amount of usage of gas. We increased the temperature to 19 degrees and still the same usage, one day we increased to 20 degrees still had similar usage... might be .300 difference.. it's mystery... even British Gas suggesting that we are using much more gas than we should.

 

[Harry Bloomfield]

Another couple weeks without luck, we are monitoring the gas consumption every 24hrs and everyday get almost identical result. 8m3. It's definitely very strange because no matter, or we leave the boiler on all day long, or we leave the boiler off for half a day and using it only in evening, have almost the same amount of usage of gas. We increased the temperature to 19 degrees and still the same usage, one day we increased to 20 degrees still had similar usage... might be .300 difference.. it's mystery... even British Gas suggesting that we are using much more gas than we should.

Turn the heating off, record the meter numbers, then before you turn it back on record them again - the two readings should be identical.