My central heating is taking over my life!!

[chezabha]

Forgot to mention this. Check out Energy Savings Trust Grant Search for special deals on insulation.

Ah...seems like I left the floors at 1. I've re-done it and it reads as follows
The WINDOW heat loss is 0.01 kW

The WALL heat loss is 7.57 kW

The ROOF heat loss is 2.11 kW

Note down the kW readings (or print this page) then press your
browser's Back button.

If better insulation is possible, make selections with higher levels of insulation,
then calculate again to see the effect on the boiler size required.

By spending money on, say, more loft insulation you may save money on the
price of the boiler, and you will definitely save money FOREVER on your heating bills.

The required boiler output is 15.73 kW

########################

I used the calc of 0.17 there.
Floors 2
Length - 9m
Width - 8.3m
Height 2.4m

Living in Lanarkshire Scotland. Microbore, that sounds familiar. Is that the norm these days?
I've just registered with the energy saving trust and spoke with them on the phone. I've arranged for a company to estimate for cavity wall insulation.
Rad results:

Rad 1 1956 6673
Rad 2 1268 4327
Rad 3 691 2358
Rad 4 1127 3846
Rad 5 307 1648
Rad 6 564 1923
Rad 7 900 3071
Rad 8 600 2047
Rad 9 600 2047
Rad 10 400 1365
Rad 11 564 1923
Rad 12 500 1706

I'm hoping you know what to do with these figures because I don't! I've also just found out that I have 12 rads and not 11.

Sorry for the inaccurate info earlier. Hopefully this will be ok.

 

[JoeMar]

did i read this right?

the house is 7 years old and no cavitiy insulation?

 

[D_Hailsham]

Ah...seems like I left the floors at 1. I've re-done it and it reads as follows
The WINDOW heat loss is 0.01 kW

Can you actually see through the window?

Floors 2
Length - 9m
Width - 8.3m
Height 2.4m

The required boiler output is 15.73 kW

Using those dimensions I get:

Walls - 6.29kW
Windows - 2.41KW
Roof - 2.11kW

Boiler size 16.85kW. This includes 2kW for hot water, so the actual heating requirement is. 14.85kW

The radiators add up to 9477 Watts. So either it is undersized for rads or the house is better insulated than you think.

The fact that you can achieve nearly 21C with the boiler full on suggest that the house is better insulated than the calculator assumes.

I would be very surprised if the walls were not cavity filled and the roof did not have more than 75mm insulation.

Microbore pipes are popular with house builders as they are generally quicker to install (pipes are flexible so they can be bent instead of having to make joints when you turn a corner). However they do have a tendency to get blocked with sludge if the system does not have sufficient inhibitor.

 

[1john]

Are all of the radiators cold at the bottom??

 

[PEDANTICVINDICTIVEMAN]

Baaaaaa Baaaaaaa

 

[Hufty]

Am I right in thinking that you have a separate hot water cylinder heated by the same boiler? If not ignore most of this post.

How hot is the water out of the taps? If it's scalding hot you're wasting gas, and also diverting heat away from the radiators. British standard tap water temperature is 50degC I think (might be less North of the border) so the cylinder stat can be set to 40-45degC as it's low down the cylinder. You do have a cylinder stat don't you? The cylinder is lagged isn't it?

Another thing is to check that the motorised valve or valves are working properly - again if they aren't water could be circulating in the wrong way.

Finally there might be issues around the system bypass loop - esp with microbore pipe the resistance might mean that loads of water is just looping round back into the boiler.

 

[D_Hailsham]

British standard tap water temperature is 50degC I think (might be less North of the border) so the cylinder stat can be set to 40-45degC as it's low down the cylinder.

No such thing as "British Standard tap water temperature".

The recommended cylinder thermostat setting is 60°C. This is to prevent the growth of legionella bacteria in the water.

Obviously this is too hot for use at the tap and could cause permanent damage. In certain cases, e.g old peoples homes and hospitals, thermostatic mixing valves are emplyed to ensure the water leaving the tap does not exceed a safe temperature - about 40°C.

 

[chezabha]

Ah...seems like I left the floors at 1. I've re-done it and it reads as follows
The WINDOW heat loss is 0.01 kW

Can you actually see through the window?

Floors 2
Length - 9m
Width - 8.3m
Height 2.4m

The required boiler output is 15.73 kW

Using those dimensions I get:

Walls - 6.29kW
Windows - 2.41KW
Roof - 2.11kW

Boiler size 16.85kW. This includes 2kW for hot water, so the actual heating requirement is. 14.85kW

The radiators add up to 9477 Watts. So either it is undersized for rads or the house is better insulated than you think.

The fact that you can achieve nearly 21C with the boiler full on suggest that the house is better insulated than the calculator assumes.

I would be very surprised if the walls were not cavity filled and the roof did not have more than 75mm insulation.

Microbore pipes are popular with house builders as they are generally quicker to install (pipes are flexible so they can be bent instead of having to make joints when you turn a corner). However they do have a tendency to get blocked with sludge if the system does not have sufficient inhibitor.

Thanks for all your help and advice today. Walls are def not insulated as a few of the neighbours have have it done recently and all houses here were built by the same "Burger Chain" I'll see what the cavity wall guy says when he comes and I'll post any update.

 

[chezabha]

British standard tap water temperature is 50degC I think (might be less North of the border) so the cylinder stat can be set to 40-45degC as it's low down the cylinder.

No such thing as "British Standard tap water temperature".

The recommended cylinder thermostat setting is 60°C. This is to prevent the growth of legionella bacteria in the water.

Obviously this is too hot for use at the tap and could cause permanent damage. In certain cases, e.g old peoples homes and hospitals, thermostatic mixing valves are emplyed to ensure the water leaving the tap does not exceed a safe temperature - about 40°C.

I've just removed the panel that houses the hot water tank for the first time. A drayton HTS3 3 is strapped to the tank and set to 75 degrees! The mis position actuator seems to be working ok between WMH. There is a Grundfos pump set to the halfway point also.

 

[Hugh Jaleak]

Water temp can be turned down, 60C is a minimum to prevent Legionella bacteria developing, but should still be ample for hot water needs.

 

[Hufty]

Sorry about the careless weekend post, my point was not to forget about the cylinder. If the stat is set excessively high, it can account for "missing heat" in a cold house.

D_Hailsham, there will be a BS tap water temperature, probably in BS6700. I seem to remember that 50deg being the only new thing I learnt from some combi course I went on so it's probably not even correct. Yes we should all worry loads and loads about legionnaires disease in domestic hot water systems and car screen wash bottles but that’s for another thread. If you are worried, original poster, 60deg is the magic bullet number, if you’re not, you could have the stat a bit lower but maybe not 40deg as I put originally. Of course this cylinder stuff probably has nothing to do with why your house is cold, just thought you should check.

 

[D_Hailsham]

D_Hailsham, there will be a BS tap water temperature, probably in BS6700.

The only reference I can find is a recommendation in BS6700 that the hot water temperature should not exceed 65°C.

Current Building Regs, in Approved Document G, now require the installation of a device which prevents the delivery of hot water to a bath which exceeds 48°C. Nothing is said about washbasins or showers.

 

[Hufty]

RTFBS! Have a look at 6700 5.6.3. Would just like to make clear that I haven't read it or anything I just searched for 50degC. Anway it's a side issue.

 

[D_Hailsham]

RTFBS! Have a look at 6700 5.6.3. Would just like to make clear that I haven't read it or anything I just searched for 50degC. Anyway it's a side issue.

But 5.6.3 is headed: Prevention of contamination of drinking water by legionella. It is nothing to do with safe water temperatures, i.e preventing scalding.

5.6.3 also says:

"In order to reduce the risk of colonization of a water system the temperature of cold water in pipes and cisterns should not exceed 20 °C, and hot water should be stored and distributed at a temperature of not less than 60 °C with a temperature at the discharge point of 50 °C after one minute."

Presumably that is where you get the 50 °C from.