Faulty Heating System

karimi

Hi everybody
I moved to a new house and have a combination boiler installed which is less than two years old. Hot water and radiators in ground floor work perfect but upstairs radiators just get hot in lower parts, so the top parts of radiators are always cold. I thought there is some air trapped inside the radiators and tried to get them off by opening the air valves but there were just small amount of air inside and no water came after all or even when I unscrewed the valve open completely. I really appreciate if anybody tell me what could be the problem and how can I solve this problem.

Browntoa

is the pressure guage on the boiler showing above minimum ??

normally about 1 - 1.5 bars

if it's low it may need more pressure added via the fill valve/loop

robowen

Are you sure you have a combi ?
If there is not enough water in the system, the pressure guage will be on zero, so the boiler shouldn't fire up in the first place. ????????

If you do have a combi, look for the filling loop, or filling key and replace missing water as Browntoa has advised you to do, remember to shut the tap off when you've filled it to 1-1.5bar. After releasing any air from the radiators, the guage will drop again, so keep filling it up.

If you are unsure, let me know which boiler you have , or take a photo of it.

karimi

Thanks Guys,
the boiler is combi. i have no access to the boiler at the moment (i will go back home at 6) but i think the pressure was not very low. the model is Ideal Boilers MiniC24. i can send you pictures or any other info that you like because i have the technical manual of boiler. i also check the pressure gauge and let you know the pressure as well. i don't know where is the filling loop and how can fill it. i think i need some more guid to do that.
Thanks,

grumbler

karimi wrote:

I thought there is some air trapped inside the radiators and tried to get them off by opening the air valves but there were just small amount of air inside and no water came after all or even when I unscrewed the valve open completely.

Make sure that
1. there is water in the expansion tank (usually in the loft)
2. the tap connecting the expansion tank to the system is opened.

You can find a lot of information on http://www.diydoctor.org.uk -->'DIY Projects'-->'Central Heating...'

robowen

grumbler wrote:

Make sure that
1. there is water in the expansion tank (usually in the loft)
2. the tap connecting the expansion tank to the system is opened.

You can find a lot of information on http://www.diydoctor.org.uk -->'DIY Projects'-->'Central Heating...'

You don't have expansion tanks in the loft with combi boilers, they don't need them.

karimi

thats right. there is no expansion tank. the pressure gauge shows something around 0.5-0.6 bars. i am not sure if it is enough or too low?

robowen

Find where the filling loop or filling key is and top it up to 1-1.5bar, then goto your rads and remove any air.
go back to the flling loop and fill again till your back to 1-1.5bar.
You have to keep doing this until all your air is out and the system stabilizes at 1-1.5 bar.

karimi

I have checked the installation and servicing manual to see where the filling loop or filling loop is, but I couldn’t find anything with this name. Is there any other name for this part?

robowen

karimi wrote:

I have checked the installation and servicing manual to see where the filling loop or filling loop is, but I couldn’t find anything with this name. Is there any other name for this part?

If there is no mention of it in the manual, you won't have an in-built filling loop.
A filling loop wil be fitted and it will be a flexible hose type thing under the boiler. It has a black lever on that you turn to let water through.

karimi

Thanks Robowen,
i will check it and let you know