bleedin bleeding! What's wrong with my system:

MuffinsDa

I have a 3 storey old house with a mix of old and new radiator and pretty crappy plumbing in general.

I have a number of radiators with cold spots on each of the 3 floors. I have tried bleeding them, when I do that, I wait till some water comes out of the cold rads but after I do that a number of times, they still don't heat up.

It's a pressurized system, Worcester-Bosch boiler (not combi), pressure at boiler when hot shows between 2 and 3 bars.

What am I doing wrong?

Thanks!

tommythecat

Are they cold at the top or the bottom of the rad? You may have sludge in the system that needs to be cleaned out?

MuffinsDa

tommythecat wrote: »

Are they cold at the top or the bottom of the rad? You may have sludge in the system that needs to be cleaned out?

Thanks for the quick reply!

don't remember exactly, I think mostly top but I will check it later this evening when I'm back home.

Is cleaning the sludge something I can do myself or do I need to get a professional.

It's an old, frail system (i.e. probably ancient pipes) so I would power flushing could be a bit risky? But what do I know about plumbing...

FWIW we also have one of those magnetic cleaning things that removes ferrous debris, right next to the boiler. I used to clean it often but haven't done that for ages. I would assume that has nothing to do with this problem though?

John.G

Some of these magnetic filters also have a "strainer" so certainly no harm in removing it again and cleaning out, especially if not cleaned for ages.

tommythecat

MuffinsDa wrote: »

Thanks for the quick reply!

don't remember exactly, I think mostly top but I will check it later this evening when I'm back home.

Is cleaning the sludge something I can do myself or do I need to get a professional.

It's an old, frail system (i.e. probably ancient pipes) so I would power flushing could be a bit risky? But what do I know about plumbing...

FWIW we also have one of those magnetic cleaning things that removes ferrous debris, right next to the boiler. I used to clean it often but haven't done that for ages. I would assume that has nothing to do with this problem though?

If they are cold at the top then you really should just have to bleed them to remove the air and they should heat up then. if you bleed them and the air stops coming out but no water then you may not have enough water in the system.
Cold at the bottom would indicate sludge that needs to be cleaned out. I'm sure someone with more experience can explain the best thing to do in that scenario.

MuffinsDa

thanks. reading about the symptoms of sludge online, it looks increasingly to be the case.
When I got a new boiler 8-9 year ago, I was told that due to the age of plumbing in the house, power flushing may not be a good idea as it can cause other problems with the existing pipework. Do you learned people agree with that statement IN GENERAL? Is there any company that does power flushing by removing each radiator and doing it in isolation like some of the DIY stuff I've seen online? Or is that too time consuming (We have 12 radiators!)

Wearb

MuffinsDa wrote: »

thanks. reading about the symptoms of sludge online, it looks increasingly to be the case.
When I got a new boiler 8-9 year ago, I was told that due to the age of plumbing in the house, power flushing may not be a good idea as it can cause other problems with the existing pipework. Do you learned people agree with that statement IN GENERAL? Is there any company that does power flushing by removing each radiator and doing it in isolation like some of the DIY stuff I've seen online? Or is that too time consuming (We have 12 radiators!)

Not enough hotwater circulating in the heating system can cause similar symptoms. This can be caused by not enough heat produced to match demand, wrong settings (or sized) on circulating pump or incorrectly sized piping.

In an old system it's likely sludge, but I add my twopence worth just in case.

MuffinsDa

Wearb wrote: »

Not enough hotwater circulating in the heating system can cause similar symptoms.

This is interesting. The boiler is usually at lowest setting and on all the time so it may be the case. We occasionally set it to highest setting every few days. but the pressure gauge in the boiler is quite high (between 2-3, in the red zone actually), doesn't that tell me that there's enough pressure (of lukewarm water) there?

Also, on a diff note, I'm always hypochondriac about legionnaire's. I presume if I set it to the highest setting for a few hours before bleeding as well as talking the usual precautions (not inhaling droplets and not letting it get all over the place) would provide enough safety against?

Dane29

tommythecat wrote: »

If they are cold at the top then you really should just have to bleed them to remove the air and they should heat up then. if you bleed them and the air stops coming out but no water then you may not have enough water in the system.
Cold at the bottom would indicate sludge that needs to be cleaned out. I'm sure someone with more experience can explain the best thing to do in that scenario.

Hi,
If not enough water in the system, how do you put enough water in it?? Sorry if stupid question!

Thanks
D