heating problem

[Tezzuk1]

1st of all hello, forgive me if this is a long 1st post but it driving me nuts, I believe I know answer but keep being by installers I’m wrong
Last year my 1 bedroom ground floor flat had new central heating installed , and it’s been bloody freezing ever since , they have check TRV , room stat against a digital thermometer ect ect all is 100% , They told me the WHOLE flat was designed to heat to a min 21c , yet even with it on all day it’s never above 15 worst when it’s really cold , yet by my calculations they about 25% UNDER BTU need of rads , the boiler is shutting down on return temp of water and longer its left on the more it shuts down , I have set every TRV to max and boiler to max . Still will not heat flat
The system is a new Valiant ecoTECplus 824; rads are Stella with Honeywell TRVs
I’ll give you 2 rooms and see what you think, the flat is council of older design, has solid uninsulated concrete floors, the walls are 4inch brick dry lined the double glazing is pre 2002 and don’t work very well, the ceilings are concrete again uninsulated, party walls are 4inch dry lined each side, with no heating on in flat the floors can get so cold you can feel damp on them and the condensation actually freezes on inside of windows when really cold

Living room is 15x11x8, one outside wall that’s is almost all glass, door and big window they have fitted a Stella Rad with btu of 5145 in middle of longest wall

Bedroom 16x9x8 2 outside walls one 16 and 1wall 9 half taken up with a window rad is under this window they have fitted a Stella rad 4589btu

Hall is 10x5x8 with front door direct to it and an unheated kitchen of same hall that’s very cold and have fitted a stella rad of 1525 btu in hall and nothing in kitchen

So either they not taken in account my variables, or based there calculation on a moden well insulated property as all of the basic calculators I can find suggest my rad are 25% under at least , the installers insist they worked it all out to correct BTU but refused to supply calculations and if im cold call council , council says to call installers

Thanks for your time

Tezz

 

[muggles]

Boiler is too large for the system, could be part or all of the problem, if you're correct about the radar being undersized that won't help but as its relatively warm outside now they should cope easily. Turning the boilers power down in the diagnostic settings would be my first move though. Are you getting any fault codes?

 

[Tezzuk1]

Thanks for reply

yes i looked at btu of boiler and its masive , nope no fault codes at all the whole system has been check twice by installers and all 100% working ok , they said the return temp was shutting it down as its supposed to , problem is i think rads are too small and not reducing the return temp of water , if i turn boiler heating temp down its shuts down for even longer and problem get worst

by my caculation living room rad wants to be about 7,000 and bedroom , 6500 and no idea on hall as it has an unheated kitchen off that , which means if door open you heating that as well

 

[dcawkwell]

if the radiators are all hot and the flat isn't heating up there is nothing wrong with boiler or controls. it is simple the radiators aren't big enough to supply enough heat to the building. I would get they have supplied
two panels with a single convector or just singles radiators with single
convectors.
I have the same in my house. On cold days I could leave the heating on all the time day and night and I still wouldn't get about 14-15 degrees. I have increased a few radiators and now can get it to 16-17 degrees.

 

[Tezzuk1]

yes Rads get red hot , even walking to other side of room you can feel a real drop in air temp , i think its as simple as they made a mistake on rads , they recon by there calculations Rad for living room is over spec its a stella twin panel twin convetor 450x1100 in a room 15x11x8 with poor insulation, concret floor no insulation , crap walls and almost 1 glass wall with old double glazing so not upto current standards

even the most basic calculation make the rad need 6600 add in a few variables i have and im way over 7,000 , i just cant see how they can think a 5,000 btu is correct it even looks tiny in room and not in best place either

 

[Tezzuk1]

if anyone has a fancy rad calculator on there PC i would be curious to know if my calculations are correct , i belive the heating company use MEAR but i know it all depends what they inputting

i use the basic L x W x H x 5 for livingroom and also

http://www.radcalcs.com/

i came up with 6600 btu and 7020 btu , the instaler said the fitted 5000 btu is over spec thats a hell of a difference

 

[Tezzuk1]

ok now im going nuts , i joined and use Stella Rads own online calculator and put in what best matches my flat and guess what they recon 8,000 btu LOL it a head fek thats for sure

problem is the construction of my flat , external walls are 4inch brick and then dry lined with a big cavity , floor is concrete ontop of dirt , party wall is just 4inch block drylined both sides and my internal walls are just stud and board , celing is concrete , double glazing is pre 2002

I know rad are 2 small as im freezing problem i have with all these different answers im having a real problem proving it

 

[Tezzuk1]

Iv used this you have to register but just takes a few mins

http://www.starsapp.co.uk/

still getting to grips with it , but it gives you a more detail set of peramiters lets you pick rads and all kind of stuff and interesting to see the U values of different kinds of construction and how poor these are for my flat, no idea how correct it is

But so far for LRoom the basic of LxWxH x5 (this i added 15% for my poor construction), radcals and stars all seam to come out around same mark between 7,000 an 8,000 due to very odd construction of my flat its hard to narrow it down 100%

So im at a loss as to how MEARS came up with 5000 being over spec unless they input a modden set of U values for my flat

 

[Tezzuk1]

I know im a pain , now asuming im way off mark and just for a min there cals are correct anything else it could be or i could try

I know all the return side valves are fully open , should they be ?

anyone know where i can get a list of what all the codes mean in diagnostic list on my Valiant ecoTECplus 824

as has already been stated this boiler is way over my needs , i think they just got same boiler for 1 bedroom as they did 3 bedroom flats and house

as said the room stat in hall if set at 15 never shuts down as flat never reach that temp , yet once boiler i guess return tems reached that shuts down

I still think its Rads but would like to give installers befit of dout and possiblity it just settings

 

[Tezzuk1]

found codes put heating on set to max temp , all trvs on full , rads hot room cold

d0 shows 19

d40 shows 74
d41 shows 73

the difference in flow and return dont seam right to me after heating only on for short time , i turned room stat back and it click of at 12 and as this has been checked with a digi thermomiter means my heating already shut down at 12c

 

[warmadmax]

problem you've got is you've not got enough rad's / large enough radiators.

the boiler can only heat the water safely up to 80c or there abouts before it cuts out and waits for the water to cool.

if the radiators are scorching hot but the room cold, the radiators can't output enough heat from the CH water, as you can see from the return temp.

the return temp should ideally be 15 to 20 degrees cooler than the flow temp when the radiators are drawing off heat from the system.

the boiler is a "peak" 20 odd kW for the central heating, can modulate down to about 7kW, with 23kW peak for hot water, definitely oversized for just 2 radiators.

8000 BTU = 2.344 kW


How many radiators have you got and are all of them hot ?

 

[Tezzuk1]

thanks for reply

i have 4 rads total
1x 5145
1x4589
1x1525
1x1768 BTU

so if my cals are correct boiler way over size

Iv attempted to balance rads unsing locksheilds only very crudley and has helped a bit , boiler now fires for longer but rooms still not hot now got flow on 75 return to 71 which i still think is to close , considering this system was supposed to be desgind to reach a min of 21c in all rooms as spec by council its crap

I guess i just keep arguing with them all till they sort it

 

[warmadmax]

it also sounds like they should be tackling the thermal losses if possible,
i bet upstairs is loving their lovely warm floor

 

[Tezzuk1]

it also sounds like they should be tackling the thermal losses if possible,
i bet upstairs is loving their lovely warm floor

i m not sure how much they can do about loss

the floor is concrete no insulation on dirt , celings concrete , outside walls are 4in brick and drylined cavity on inside , internal just stud and party walls are block and lined double glazing is old but no chance of them changing that

But the heating installers were fully aware of the construction so should have allowed for this , now question is did they make the subbie aware when he order rads each flat had a taylored install as ive not seen 2 the same , they removed the warm air heating that worked perfect , heated flat great and replaced it with this so called upgrade LOL

its about 11c hear today and been messing with heating so its been on for about 3 hours best temp i got is 16c , imagin how cold it gets when outside temp drops to -1

 

[Tezzuk1]

been trying to balance rads ect got flow and returns a bit better on d40 d41could not work out why bathroom rad pipes both hot as in no change even on ajusting locksheild , have now they fitted TRV on return pipe , as i only have 5KW rads turned boiler down to 10KW will see how that gose

One thing i have noticed with this boiler is that even when tuned of over night it uses about 40-50p of gas , im guessing in built frost stat