Hi,

 

A friend asked me to look at his sisters heating today, the downstairs rads are not right. The two larger ones at the front (furthest from the boiler) just don't heat up and the 2 smaller ones take an age to warm up. I'm thinking both sludge and balancing as the flow pipework up to the rads gets hot but the rad just takes for ever.

 

I tried shutting down rads and trying to force the hot water round the radiators but still so slow to heat up. Pump is already turned up to max.

 

I wouldn't say the upstairs rads are brilliant either..........

 

It's a conventional system. Any ideas on things to try next?

 

Cheers

 

Vijay

thermostatic valves stuck, take the heads off and try pulling the pins up

 

could also be airlock, try turning them all off then just truning one on to push the air and heat around, also might be worth trying to pull some water through, if it has heating tanks just open the drain off tap and let soe water out while it fills up, sometimes the air gets stuck and stops it circularting

only the upstairs rads have thermostatic valves. Downstairs are just normal ones.

 

Could it still be an airlock if when I opened the air vents on the rads, I get water under pressure?

is it a combi?

No mate, conventional system. Hot water is still fine. Just the rads are crap

also the vavles could be goosed, are both sides turned on fully, the lockshield and the control valve

 

if it's not a combi and you are still getting water ot of the rads when bleeding it could still be air, rads are full but air is stoppong the flow of water

 

balancing might work, obviously turning the rads closer to the boiler down with the valves will push the heat to the rads that aint working

 

as said, try turning all the ones off that work and the ones that dont turn on one by one to see if the air will be pushed to them

Yep, tried both valves open.

 

I tried shutting down the rads and leaving one on, still the same thing - pipe and valve got hot but rad just got a touch warm and took forever to get to that

strange, could maybe be sludge, only one way to find that out though, you would have to take one off and wash it out

is there a heating tank? is there enough water in it, sometimes the ballvalbes get stuck and the tanks empty

strange, could maybe be sludge, only one way to find that out though, you would have to take one off and wash it out

 

That's exactly whay I thought but light coloured carpets and it's always a messy job as I'm sure you know ;)

is there a heating tank? is there enough water in it, sometimes the ballvalbes get stuck and the tanks empty

 

Didn't check that. I assume the water level is fine though as most rads will get hot after a long while (certainly the upstairs ones). And the downstairs one is where water came out of the air vent

plenty of dusheets and pans lol, or turn the carpets back

 

im glad i dont so much plumbing these day's jobs like this can be a nightmare, can be like a missfiring zed, could be anything lol

Process of elimination I guess......................... Be alright if I was being paid! lol

oof, love jobs even worse lol

 

but as you say, its a process of elimination unfortunately

certainly sounds like a flow issue, you can rent powerflushing machines if you dont know anyone with one. or failing that as Al says take one of the worse affected rads off and get the hosepipe on it.

 

When you try and bleed them what comes out? clean water or black water?

Also lower the pump speed back to 1 or at the most 2.

 

Are the pipes off the pump hot ? if not may be sludged up impeller in pump

blackish water comes out of the rad air vents

 

Yes the pipes off the pump are hot and I can hear the impeller spinning.

blackish water comes out of the rad air vents

 

Yes the pipes off the pump are hot and I can hear the impeller spinning.

 

Most systems out there will show black fella, its not the colour of the water but the sludge content!

 

Sounds like the pump is ok make sure the pump speed is lowered.

 

Water will always go down its easiest route if the pump speed is to great the water may bypass the rad circuit you are having probs with!

 

If the rads are a managable size the best thing to try as said is to remove them and put a hose onto one end and then rock the rad back and forth and flush the muck out if still a problem get some sentinal x800 cleaner add to a rad or header tank run the system as hot as you can for 2/3 days then drain system.

 

Hope this helps

 

Dave

blackish water comes out of the rad air vents

 

Yes the pipes off the pump are hot and I can hear the impeller spinning.

 

 

Have you checked the pressure on the boiler unit? Are you bleeding the rads when the heating is on and the pressure is higher to help push the air out?

 

Failing that I would drop the water then refill and chuck a rad flush through it and leave that to run for a while before pulling radiators off to check them and messing with valves, will be alot less hassle if it works

Have you checked the pressure on the boiler unit? Are you bleeding the rads when the heating is on and the pressure is higher to help push the air out?

 

Failing that I would drop the water then refill and chuck a rad flush through it and leave that to run for a while before pulling radiators off to check them and messing with valves, will be alot less hassle if it works

 

It is not a combi fella

we have had probs with ours for about 2 years. kept bleeding rads then after couple of days they would be hot at the bottom and cold at the tops.

got a bloke here right now power flushing the system, hopefully all will be ok then

The rads are heating up from the top down and the bottom channel of the rad is not warming through so it looks like sludge build up.........

 

I've ended up getting some Fernox cleaner so gonna throw that in this afternoon and let it try and break things down over a week or two.

It is not a combi fella

 

I know bud, the central heating boiler I just replaced still has a dial for the water pressure

I know bud, the central heating boiler I just replaced still has a dial for the water pressure

 

some systems have a pressurised heating boiler like a combi but also have tanks and hot water cylinders

 

sounds like a build up of sludge to me, best bet is to take them off one at a time and flush out with a hose

Do you have to deal with alot of blocked systems Stella? Does it occur due to the absence of a rust inhibitor?

i dont do a lot of plumbing these days but over the 16 years i have been plumbing i only ever did one, took every rad off and cleaned out, replaced thermo valves and it all worked