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New heating system not heating house

(26 Posts)
inmyshoos Sat 26-Nov-16 22:59:43

We had an old stove with back boiler, heated rads and water. I felt although rokm with stove was toasty it took a lot to get rads really hot. So we have had a brand new system put in. Lpg as rural so limited options. New rads, water tank pipes etc.
I expected heating to be on an hour and house would get toasty but infact the rooms feel quite cool and are struggling to get up to the 20°C that i have set it at.
My Dad thinks the boiler isnt big enough. Its a 24kw - 11 rads and a 300 litre unvented water tank. Online it says that boiler can do up to 10 rads so maybe he is right. I am so disappointed. House has been ripped apart and now we are colder than before.
Anyone know about these things?

inmyshoos Sat 26-Nov-16 23:03:40

Just to add that the heating had been on from 7.30 this morn (it is very cold here at moment -3ish) and by 9 it was still only 15°c with heating fully on. I am expecting too much? It is an old house with stone walls but double glazed and well insulated and max one ouside stone wall in any room due to extending.

iknowimcoming Sat 26-Nov-16 23:09:28

Is your heating and hot water both on at the same time? If so one hour wouldn't be enough as hot water will take priority over heating. It could just be you're not using it quite correctly (don't mean to sound rude). In my house the heating is set to come on an hour before we get up and the hw half an hour earlier. In the evenings it's on until half hour before we go to bed. If your don't run it often enough or long enough the house temp will struggle to come up, best to leave it on lower for longer to maintain a more constant temp imo.

iknowimcoming Sat 26-Nov-16 23:13:05

Also you should check each radiator when the heating is on to see if they are all getting really hot. Make sure all rads are turned up to max. Have you spoken to the installer about your concerns?

Ineedanewbody Sat 26-Nov-16 23:16:28

I had something similar and found if I turned the temp setting up to 24-25 the house heated up better.

inmyshoos Sat 26-Nov-16 23:27:29

iknow yes still experimenting with it but have spoken to installer about my concerns. Rads are sll getting piping hot but still struggling to get rooms comfortably warm.

ineedanew i'm just nervous about how much lpg we are going to use. Seems like the system is having to work quite hard to get the house warm.

PigletJohn Sat 26-Nov-16 23:31:07

Are all the radiators all fully hot? Top and bottom, both corners?

how do the radiators compare in size with the old ones? (I may ask you to measure them later)

What temperature does your boiler indicate?

24kW is quite a lot and adequate for most houses, even old ones.

The cylinder might take half an hour or so to warm up, in cold weather you can time it to start half an hour before the radiators come on. What colour is the cylinder?

Have you closed the internal doors?

Namechangingbastard Sat 26-Nov-16 23:33:53

Try placing something reflective behind radiators to bounce the heat I to the room rather than heating the wall.

inmyshoos Sat 26-Nov-16 23:40:22

The radiators are similar size but have been relocated because a few were previously under windows. They are mostly now just as you come in the room in the dead space where the doors open.
Boiler saying anything between 65 and 80 depending when i look.
I am glad you think 24kw sounds ok as the installation was traumatic enough, i don't need another week like the one i have had!!
The water cylinder is white, looks like a megaflow but is William Wilson one.
The thermostat had been placed in hall (small)which has a very large radiator (bigger than one in big lounge!) So the heating kept going off when hall was at 20°c however everywhere else was like 15/16 °c. Have moved thermostat to lounge which has helped but still feel it is taking quite a while to get the place warm.

inmyshoos Sat 26-Nov-16 23:44:00

Oh sorry yes rads are all hot top and bottom. Ones that are furthest ftom boiler are very slow to get hot however. There was chat about needing another pump bug our house isn't exactly a mansion! From boiler to furthest rad is around 12m - house all on one level.

Meadows76 Sat 26-Nov-16 23:46:55

Turn the thermostat up

inmyshoos Sat 26-Nov-16 23:53:45

meadows it was originally at 18°c as per advice from installers. Its now set at 20, however the problem is that even with it set at 20 an hour and a half after turning it on room is still reading 15/16°c

PigletJohn Sat 26-Nov-16 23:56:42


Turning up the roomstat will have no effect on the heat delivered by the boiler or the radiators. All it will do is prevent the heat going off once the rooms become uncomfortably hot.


The white cylinder, once hot, is very well insulated, so you can certainly set the HW timer to come on prior to the radiators. Unless you have two baths or multiple showers in a day, it will probably not run out of hot water until you heat it up again the following morning. If it comes on an hour before you get up in the morning, it will stop using heat from the boiler once it is fully hot, which will be in the region of half an hour to an hour. It will absorb less heat the hotter it gets. From fully cold, it will absorb a lot.

As you are on LPG, do you have a meter or other way of measuring the amount of gas you use? Or does your boiler show "bars" or flame size to indicate whether it is running at full power, 50%, 25% of capacity? Modern boilers very seldom run at maximum power for long (unless they are combis) and they are noisier, and produce more steam, when they do.

If the house has been unheated for a while, the fabric of brick and stone ill take a while to warm up. It may take a couple of days of string heating, as you have an old house and some stone walls.

inmyshoos Sun 27-Nov-16 00:06:26

Not sure if boiler shows bars or flames to show what capacity it is running at. There is a flame on while its heating but not sure what else. Boiler is a worcestor bosh.

Will try messing about with it and see if i can get it right. Maybe we just need to get used to each other grin

It's good to know you don't think the boiler is too small Pigletjohn as that was a worry!

PigletJohn Sun 27-Nov-16 00:14:40

I think it needs more balancing, especially to reduce the heat output of that large radiator in the small hall, but that is fairly simple (if time consuming). Do you have TRVs?

If it is frosty tomorrow, you can look out and look at the steam plume. The harder the boiler is working, the more steam. As your ear becomes attuned, you will hear the internal fan running faster, and the flame size getting noisier as it gets bigger. If you are next to it when the timer kicks in, it will be quite noticeable.

Meadows76 Sun 27-Nov-16 00:30:30

Turning up the roomstat will have no effect on the heat delivered by the boiler or the radiators. All it will do is prevent the heat going off once the rooms become uncomfortably hot.. The reason I said to turn it up was to see if it made a difference confused often people have to have their stats set to 25 to achieve 20 throughout

PigletJohn Sun 27-Nov-16 09:07:16

that suggests a balancing error, where the room with the thermostat heats up faster than other rooms. It should be balanced to heat up slower or the same.

inmyshoos Sun 27-Nov-16 09:57:49

All rads APART from hall one (it's the by pass one ?) have TRVs.

Heating been on since 7.30 thermostat in lounge reading 19.

user1471505356 Sun 27-Nov-16 10:35:38


PigletJohn Sun 27-Nov-16 10:42:31

Ok. It is correct not to have a TRV on the radiator where the thermostat is. However, the radiator in this room has to be regulated so that the room heats slower than all the others. This is done by balancing.

If your heating installer is still tinkering, he should do this for you. If not, it is an easy (but slow, because after each adjustment you have to wait half an hour to gauge its effects) DIY job.

Do you want to have a go?

Also, go round all the rooms (preferably with a thermometer) to gauge if any have reached their target temperature. If so, the TRV should be closing and opening to maintain that temperature, you may detect that the radiators are no longer fully hot at one of the bottom corners.

Don't fling TRVs to max or min setting. Round about 3 is usually correct.

You do need to keep internal doors closed when regulating the heating.

inmyshoos Sun 27-Nov-16 18:03:45

Thanks pigletjohn i will have a go at balancing things out. Where is a good place to start? Should i turn all trv off and do them 1 by 1?

PigletJohn Sun 27-Nov-16 18:26:27

no, you leave the TRVs fully open, and adjust the lockshield at the other end. For the one in the hall, which sounds like it is throwing out too much heat, I'd try screwing the lockshield all the way down, then one full turn up, and see if the rad, after half an hour, is warm all over bit hot (only) at the Flow pipe.

The principle of balancing is that you turn down the hottest radiators. This causes more heat to flow to the others.

For more, see How to balance radiators by PigletJohn

inmyshoos Mon 28-Nov-16 00:43:11

Thank you so much pigletjohn i will get on to it tmrw flowers

Alwayscheerful Wed 30-Nov-16 10:22:21

We have a large old house with a new boiler approx 30kw. It is very slightly underpowered for the amount of radiators. We knew this when we ordered it however the next size up required a bespoke boiler room (thousands extra) We added a heat storage cooker (Everhot) and a large wood burning stove - if we add up the total output from the boiler, Woodburnet and Cooker it is sufficient. In mild/ normal weather it is fine but during very cold spells the installer told us to heat the hot water first i.e. 5-6 am and then the radiators 6am onwards.
We occasionally turn a couple of radiators off or down to make the rest of the house warmer.
I have also learnt to balance the system piglet John style.

inmyshoos Mon 05-Dec-16 08:41:52

Thought I had it balanced but this morning it is -9 outside and heating has been on since 6.30 and off at 8.30. It only managed to get the lounge up to 17° in that time. Thermostat read 15 before heating came on. Is that normal because it is sooooo cold outside? I have boosted heating for an hour and going to light fire in a mo! Going to walk the dogs now too so that always makes house feel warmer - coming in from -9°!!!
alwayscheeful how large is your house? Ours isn't huge but all on one level and I do wonder if that doesn't help. Certainley the rads at far end of house (opposite end from boiler) are only just getting hot hot after 2 hrs this morn! Fortunately they are bedrooms in a well insulated part of house so not too much heatloss once warm.

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