Why so little heat?

[richrich123]

Hi,

Can anyone suggest why I get so little heat from my radiators. They are hot all over with no cold spots so i presume it is not a trapped air issue. i have however bled them all a little anyway.

They all get hot but the amount of heat that rises from them is not very much and it often takes several hours to increase the heat in the room by a couple of degrees.

The boiler is old, an apollo myson but seems to work fine. It is only a 1 bed house with 3 single rads and 1 double so i cannot see the boiler is underpowered.

The pipes that feed the rads are the smaller type (less than the standard 15mm)

Has anyone got any suggestions what the problem could be.

Thanks

 

[gas4you]

Radiators too small for your rooms perhaps?

 

[ColJack]

poor insulation on the walls / windows.. etc..
with it sooooo cold outside the heat is rushing out through the walls and windows as fast ( or almost ) as you can put it into the room..

 

[richrich123]

Thanks olJack and gas4you for your suggestions...

poor insulation on the walls / windows.. etc..

On my HIP it was awarded an A rating. The inner and outer walls are full of foam, all windows and doors are double glazed and all rads have the silver heat deflectors behind them. Being a terrace, there is also only 1 exposed wall to the elements.

Radiators too small for your rooms perhaps?

The radiators are about 5 feet wide for a room that is about 10x10 feet so if anything, probably bigger than needed.

I appreciate that boiler or rads could be improved / upgraded and that would help with how long it takes to get the house to a comfy temp (normally have it at 22 oC) but the radiators, even after being on for several hours are only giving off a small amount of heat if you hold your hand over the top.

In my previous property, after abount 30 mins, the rads would be so hot you couldn't touch them for more than a second and the heat poured from the top.

In this new property, when the rads reach peak temperature, while they are quite hot to the touch, there is only a small amount of heat rising from them. The problem (as far as I can see) seems to be that the temperature of the water being pumped to the rads is not red hot and for that reason, the heat being emitted is limited.

On my hot water tank, I have a dial to control its temp, is there a way to control how hot the water is thats being pumped around the rads? The only option my boiler has is a high or low setting. low for summer, High for winter, it is set to high. I don't have thermostatic valves so nothing is reducing or stopping the temp of the rads getting any hotter, I presume they are only getting as hot as the temperature of the water being pushed into them which seems to be below average and needs to be hotter.

Cheers

 

[Burnerman]

Maybe your previous rads were double row, double convector ones which gave out lots of heat.....are yours comparable by design?
Check out pics in Screwfix etc for examples.
John

 

[richrich123]

No, you prob have a point there, my old ones were all quite new so probably a lot better design. Maybe thats the reason then, the rads are just old and not very good at giving out the heat.

As a side point, the pipes in are smaller than the normal 15mm, I would guess they are about 10mm (ish) Is that a problem? I guess I could get a 10mm > 15mm converter if I was to chage them over. Maybe that could be the problem that they are not carrying much water as they are so much smaller than 15mm??

 

[Bahco]

Have you turned the boiler thermostat up ?

My solution if I was keeping the house is.............If you are able to do it yourself then you should definitely change to 15 mm pipe as well as a flush out and then balance the system too.

Change the 4 rads too while you are at it.

£300 will cover it easily as a DIY job.

 

[Burnerman]

Don't worry about your pipes not being 15mm (sounds like they are 10mm microbore) that isn't an issue.
Your rads should get too hot to comfortably touch really if you have the boiler stat turned up but the single row or single row one convector types just cant dissipate there heat anywhere near as efficiently as the twin types.
I can see heat shimmering over one of my twin row twin convector ones - in fact it moves the curtains - yet another single row one does nowt even though you could fry chips on it.
John

 

[richrich123]

I do not seem to have any controls on the boiler for

Have you turned the boiler thermostat up ?

Do you mean the thermosta in the room? If so, yes, it is set to 30 oC although the room is currently at 21 and only climbing about 1 deg per hour.

I can see heat shimmering over one of my twin row twin convector ones - in fact it moves the curtains - yet another single row one does nowt even though you could fry chips on it.

Thats exactly my problem, and what I used to get in my last house. sounds like I need to upgrade to newer rads then really.

If you are able to do it yourself then you should definitely change to 15 mm pipe

I can do it myself, I'm fine with plumbing,and radiators but I think to change all the pipes to 15mm would be hell as downstairs they are all set in the concrete in the floor and just rise at the point of the rads.

flush out and then balance the system too.

I am sure it could do with this, the house is 16 years old and the boiler and pipes / rads are, I guess also all 16 years old. I was toying with having the boiler replaced when i moved in but have been quoted between £2 - £2.5 k for a replacement combi boiler, system flush and installation. I thought that was quite a lot as it is a small boiler, only needs to run 4 rads (lounge / kitchen / bathroom / bedroom).

My current boiler seem to work just fine, no doubt it is not that economical / efficient compared to a new one but it would take years to recover the £2 -£2.5k outlay for a new one based on economy savings so I thought that until the current one starts causing problems, it does not problably justify changing.

 

[Bahco]

To change all the pipes to 15mm would be hell as downstairs they are all set in the concrete in the floor and just rise at the point of the rads.

If you only have 4 rads to pipe up, you can afford to disconnect the buried ones and leave them in situ. You can then go from your boiler in nice shiny brand new copper.

 

[Nige F]

You have a 1 bed home in Sussex . then probably the rads were chucked in when it was built and they were a job lot of a couple of sizes used nationwide by the " builder" . Plumbing in Sussex since 1970 and seen it all ( nearly)

 

[ColJack]

pics of the rads will help us... and the boiler too..

 

[ColJack]

is it possible to turn the pump up?
have you got all the valves fully open?

could it be sludge in the system?