House takes hours to warm up

C

Classic40

Hi,

My house seems to take hours to get nice and warm; however once it is warm it keeps warm as long as the heating is left. House is a 2 bed semi built in late 50s, approx 70sq meters, double glazed but let's cold in still. Loads of fibreglass in the loft and cavities have been filled.

System is made up of the following.

Ideal Classic FF 340 Boiler
Sealed System Kit
Sunvic Sunpro 2000 programmer/thermostat
Honeywell 3 Port Valve
Copper RM cylinder 120L fed by a 25 gallon tank in loft
Danfoss ATC cylinder thermostat
6 Radiators
Hallway; Single 700 x 600 (2388 BTU/700 Watts)
Living Room; Single 1400 x 600 (4777 BTU/1400 Watts) & Singe 900 x 600 (3071 BTU/900 Watts) - 6.22m max x 3.48m max
Kitchen; None but piped up ready - 2.90m x 2.67m
Bathroom; Single 400 x 600 (1365 BTU/400 Watts)
Bedroom 1; Single 900 x 600 (3071 BTU/900 Watts) - 3.23m x 2.84m
Bedroom 2; Single 1000 x 600 (3412 BTU/1000 Watts) - 4.50m x 2.82m

Boiler has an output of 40,000 BTU/11.7kw.

I have the boiler set on number 5 which is approx 77c.

I have a feeling when the system they oversized the boiler and undersized the radiators.

Can anyone give any advise/tips on what I can do?

Thanks.
 
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Used the link given to work out btu needed and it comes in under what btu I already have.

I count warm as 20c yea.
 
When you worked out the BTU needed (do please move into the 1980's and use kW) how many did you calculate you needed?

Any how many BTU would your radiators provide if they were all putting out their nominal maximum (they won't be)?

BTW why are you refusing to say how long the house takes to reach 20C?

what temperature did you start at, and what was the outside temperature?
 
JohnD said:
When you worked out the BTU needed (do please move into the 1980's and use kW) how many did you calculate you needed?

Any how many BTU would your radiators provide if they were all putting out their nominal maximum (they won't be)?

BTW why are you refusing to say how long the house takes to reach 20C?

what temperature did you start at, and what was the outside temperature?
Click to expand...

Hi,

I took the BTUs of my rads from page44 and took the needed BTU from the link given above using the roomsizes.

Take this morning for example, it was 14c when I got up and 3c outside. It took around 3 hours to get up to 19c.

Sorry JohnD, I am not trying to be unhelpful, I was not sure what information everyone would need.

Thanks.
 
You were right about undersized radiators.

When I add up the nominal outputs of the radiators, I make it 4600W, so they can handle less than half your boiler's power.

They immediately look to the eye to be too small, you could easily double them or more and the house would not get too hot (the thermostat and boiler will reduce power) but it would warm up quicker. In my own home the total radiator capacity is even bigger, because I used to be away from home all week and liked it to warm up quickly when I came home.

The easiest way is to fit finned double rads of the same width as the old single ones, that reduces the amount of repiping, but IMO a wider rad gives a better spread of heat within the room.

Make your changes downstairs first, as heat will tend to rise upstairs to the bedrooms; and in the bathroom, where you will appreciate warmth. Use the opportunity to give the system a simple chemical clean, and add thermostatic radiator valves in all rooms except the one with the room stat.

You might find you can re-use some of the larger downstairs radiators in upstairs rooms, or in the hall which might be rather cold.

If you have a baby or an elderly person in the house, a large radiator with TRV will enable you to keep their room extra-warm if necessary.
 
Last year I did add some cleanser and drained after 2 weeks, fitted 2 TRVs on the living room rads and then added inhibitor.

The system was pretty clean (I had all of the rads off and flushed them out with mains water, was next to no sludge)

All of the rad's but the hallway and bathroom have TRVs.

I get 5.3kw when I add them up.

I read about balancing so I want to give this a try first to see if I can improve things.

I understand I need to buy thermometers, can anyone help with a guide and a link to buy some good thermometers?

Many thanks.
 
I bought a couple of clip on thermometers years ago when I first tried to balance my system. They were not very helpful as they were not very accurate (different temperatures when adjacent on the same pipe) and they took ages to react to a change in temperature. I now use an infrared thermometer, which gives instant readings. But you have to be careful using them or you will get misleading results.

1. They average the temperature over an area which gets larger as you move away from the thing you are measuring. Think of a torch beam shining on a wall. If the torch is touching the wall the area lit is very small, but if you are 10ft away it is much larger. So you must have the thermometer as close to the pipe as possible

2. The reading depends on the brightness or "emissivity" of the material being measured. The thermostats are normally calibrated for an emissivity of 0.95 (A black body has an emissivity of 1). If you measure something with a smaller emissivity it will give a lower reading. For example shiny new copper pipe has an emissivity of 0.04, so the temperature displayed will be considerably lower than the true figure. The way to get round this is to wrap some black insulating tape round the pipes and measure the temperature off the tape.

How to balance the system

1. Close all LS valves; then open them 1/3rd of a turn
2. Remove all TRV heads and set all wheel valves (other end of rad fro LS) to fully open
3. Set the boiler temperature to at least 75C
4. Set pump to speed 2
5. Set room stat high (so boiler does not go on and off)
6. Let the system warm up
7. Measure the temperature difference, between flow and return, at the boiler and at each rad. It should be about 11C.
8. If difference is much smaller, set pump to speed 1; and vice versa.
9.If no noticeable difference, (±1C) go to step 13
10. Go to the rad with the greatest difference (i.e coldest return) and open the LS valve opened very slightly (1/12th turn or less).
11. Wait 5-10 mins for the system to settle down.
12. Go to step 7
13. Stop
14. Set room stat to usual temperature
15. Replace TRV heads and set wheel valves to required position.

Don't aim for perfection, Provided the temperatures differences are all approximately the same at the boiler and each rad it doesn't matter what the exact difference. Though 11C is the recommended difference.
 
Should do the trick.

Ignore the laser beam. It's the large opening which contains the IR device that measures the temperature.
 
Hands are perfect for the job.......fookin around with clamp on stats etc is carp. :rolleyes:

Jeez a professional heating engineer would have a 3 bed house balanced within 5 minutes......and that's with good quality lockshields that use a screw to hold cap down. :LOL:

Next you'll be suggesting commissioning valves. :eek:
 
D

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