Hot rads, cool rooms. (Long post)

[davebuk]

Hi all

Just moved into a 3 bed detached house with a Worchester 240 combi boiler. It works fine, rads get hot enough, but all the upstairs rooms never seem to get that warm (around 14 degrees C). The down stairs is fine, except for the hall/kitchen area. All TRV valves are on full (due to the tops being broken off) and system bled. No cold spots or probs like that. Also turned the lockshields down on downstairs rads to give more flow upstairs, but no change.

Doing a rough 'cubed feet times 5 BTU calc'. the rads in the hall and kitchen are about 2000 BTUs too small to heat the landing area as well. The upstairs rads are just about the right size in BTUs for 'cubed feet times 4' for each room so there is no spare heat for the landing area. The house used to have a working open fire downstairs as well, but was removed by previous owner/builder who had just done some building work and took out the chimney.

I was thinking of changing all the upstairs rads, plus the one in the kitchen from singles to doubles. This will save on pipe work and would give around 1/3 extra heat, (is this correct)? I can replace the TRVs at the same time.

Would bigger rads upstairs solve the problem, or should I try and put a rad on the landing and increase the hall/kitchen rads to heat the hall/landing combined area. There is not a lot of spare room downstairs though for bigger rads!!

Gas bill seemed a bit high as well, so wondering if heat exchanger is on its way out. I do not think the boiler has been serviced for 4 years!!

Many thanks for reading and appreciate any advice.

 

[COG]

your roll of thumb calculation is not that bad i tend to x by 4.5 and come up with a very sim result after using a mears calculator. your problem is probably just balancing, water is lazy it will always find the easiest rout, it should have the same resistance to the closest radiator as to the furthest with the smallest pipe ,if it finds a short cut the boiler will think its heated all the rads and so ramp down the gas pressure when it may have only heated half the rads as you say,you should use the lockshield valves on your rads so that all rads heat up equally with around a 11 deg diff between flow and returns ie hottest rads at present almost off and coldest full on

 

[davebuk]

Thanks for the info. To measure the temp across the rad, is it as simple as holding a thermometer on the feed and then the return and adjusting the lockshield to suit?