powerflush, new trvs or magnaclean?

[supersadie]

Hi
I have radiators that won't heat up when all switched on. Individually they all work fine, but once all on, they're all cold. Pipework is microbore which is green with verdigris and so are the valves.
Boiler and pump work fine. Tank is a combined system on the first floor (one of the things with a coil inside separating one body of water from the other. Boiler is normal and not combi.

I have 4 of 11 rads on and they're tepid at best. Think I need a power flush. Have been quoted anything between 350 and 800. One chap reckons the trv need replacing.
Is it possible that they're the problem and replacing them might solve the problem without power flushing?
Had a flush in 2005 (only chemical I think) so unsure if it's the rads or the valves.
Any help much appreciated. I am wearing two pairs of everything, plus hat and gloves indoors.

 

[seco services]

Hi
I have radiators that won't heat up when all switched on. Individually they all work fine, but once all on, they're all cold.

if they work individually then i wouldn't suspect the trv's. more of balancing system
but you can remove the trv heads and check pins move freely and try system.

 

[supersadie]

some don't move. I guess they're all leaking to some extent hence the verdigris.

 

[seco services]

some don't move. I guess they're all leaking to some extent hence the verdigris.

how did you get them to come on Individually if they don't move ?

 

[supersadie]

Good question. The handwheels move but some of the other end (lockshield) won't budge. I think that's what happened. I know a pair of molegrips and a hammer came in handy.

And I had to put my undies on over my trousers.

 

[clearhead]

are your flow or return pipes getting hot to radiators

when your boiler fires on call for heating is your pipe work getting hot past mid-position valve position -(is valve opening properly)
trace pipe work to see whats getting hot and whats not eg to rads flow and returns-
try turning all rads off bar one closest to airing cupboard and see if that gets to a good temp and then the next and then next-just to see whats going on (this is not how you balance a system just trying to focus the heat)
can you try turning your pump up
is your boiler coming on and off more frequently than normal(getting really hot and shutting off(symptons of a blockage)

 

[kevplumb]

if the rads are heating it means you still have some flow

personally

good dose of DS40

will cure it

or kill it

don't think powerflushing will help

 

[supersadie]

Clearhead - yes - they all come on individually, except two, if I shut the others down. I've tried balancing, but no joy. Not always clear which is the in and which is the outflow.

The tail pipes are various heats depending on which radiator but mainly warm.

I have got four of the 11 on at the moment and they're lukewarm at best.

Kevplumb - do you really think so? DS40. Should I change the valves too as there's green deposit over them and the tail pipes and one of the valves can't be turned on at all as it leaks?

I guess using DS40 is a plumber type job and not an enthusiastic amateur thing?

 

[kevplumb]

I guess using DS40 is a plumber type job and not an enthusiastic amateur thing?

no reason why you can't do it

read the instructions first tho

don't change the valves till after you clear the system

if they are shot it will find them out

then change them

 

[clearhead]

clean the green with some soft wire wool-sometimes its too late for the chrome finish-if the chrome flakes it wont hurt the valve(cosmetic)
if its a lockshield thats leaking - have you tried tightening the packing gland nut-the little nut at bottom of spindle top of valve

whats your boiler stat set too

 

[supersadie]

Re boiler - I can only tell you I've got it at just above 4. There's nothing more technical than that inside the boiler that I can alter far as I can see.

The house stat is at about 18.

How would you tell what needed a chem flush and what needed a powerflush? I don't want to spend a packet needlessly, but I don't want to spoil the ship for a ha'porth of tar.

 

[supersadie]

I'd like to thank Kevplumber regarding his advice on not bothering with powerflushing.
I went for a chemical flush and valve replacement, which didn't fix the problem, although there was sludge.
We then took the t-junctions off beneath the cylinder to see if they were congested.
They weren't.
Someone on this site mentioned the threeway switch that dictates whether heating and water, one or the other come on.
I mentioned it to the plumber and he discovered ours was faulty (hence no heating without hot water being on). It has been this way since we moved in six years ago.
I now have a warm house.

Big thanks to these helpful posters!