gunk out of rad valves

[timbalcombe]

2 questions in one sorry.
Had our boiler replaced with an ecotec pro28 (not too happy with it - but a different story - try serching on vaillant to see my posts on noisy boiler)
Anywho....
today I was adjusting some rad valves. One is the nearest to the boiler.
I turned off the flow valve and a load of black gunk spilled out of it.
When I bleed the rads a yellowish liquid comes out not black, so what is this black gunk?
Perhaps the vlaves a gunged up?

As I did this I heard the pump on the boiler go into overdrive which relieved itself after I turned the rad back on.
If this valve had stayed off eg I got too hot and turned the rad off, what would happen to the boiler?

 

[Softus]

If there is black gunk oozing from a rad valve then your system is probably corroding internally. Obviously the rad valve is leaking where it shouldn't.

If you get yellowish liquid from a rad vent, then this could be many things, including the result of rotting rodent carcasses in the F&E cistern. Too little information on this particular aspect.

If turning off a radiator causes extra noise at the pump then it's possible that this rad was acting as a bypass. This is poor plumbing practise. The effect on the boiler in the short term isn't dire, because it would reach its upper limit temperature and cycle off. However, it isn't a good idea for this to be happening repeatedly.

If you had a new boiler recently then your system should have been thoroughly cleaned out internally before the installer completed the job - this doesn't necessarily involve power flushing, but not to clean out fully and leave uninhibited is shoddy work.

You can drain and clean it out yourself of course - plenty of topics have covered this, but ask if you need help.

 

[Nige F]

I left a job and drove home naked once ...........that was pretty uninhibited

 

[Softus]

But were you oozing black gunge, or a yellowish liquid?

 

[timbalcombe]

it is a combi (i thought the ecotec pro28 might have given that one away) so no F&E.
The system was cleaned with sentinal100 which I think is the yellowish colour.
The black stuff though in my opinion is either oil or similar from the valve as it is leaking so somethig has broken. When the dude installed the new boiler he warned me of the valves. we didn't have enough cash at the time to pay for his extra 100 to change the valves.

In my understanding how can the rad be a bypass?
If the feed to that rad is turned off, then the system is starved of a flow, thus creating the noise. There SHOULD be a bypass in place to combat this.
I dunno, I'm probably talking out of my jacksy?

 

[Softus]

it is a combi (i thought the ecotec pro28 might have given that one away) so no F&E.

I know, but I did say the result of rotting carcasses that, given that your system appears not to have been cleaned out, might still be there in residue.

The system was cleaned with sentinal100 which I think is the yellowish colour.

Sentinel x100 is not a cleaner. Nor will it negate the effect of a dirty system, because it's designed only to keep a clean and well-maintained non-leaking system in a clean state.

The black stuff though in my opinion is either oil or similar

In that case why are you asking for anyone else's opinion?

When the dude installed the new boiler he warned me of the valves. we didn't have enough cash at the time to pay for his extra 100 to change the valves.

There's yer problem - you should have used a heating engineer instead of a dude.

In my understanding how can the rad be a bypass?

What? By being plumbed wrongly, that's how.

If the feed to that rad is turned off, then the system is starved of a flow, thus creating the noise. There SHOULD be a bypass in place to combat this.

That was my very point.

I dunno, I'm probably talking out of my jacksy?

:shrug:

 

[timbalcombe]

sorry i misread or understood your answer/s.
How should the plumbing be then going to the radiator?

In fairness you get what you ask for;

We asked for - condensing combi, new 22m gas pipe, remove existing pipework to headers, onto existing heating system.
The engineer in my opinion did a good job. He did a cold then hot flush, and spent at least 2-3 hours on commissioning and benchmark.
At least he warned me about the valves.

Where he has fitted TRV's on the return side (omni directional TRV's) how do you balance a rad with a trv where the lockshield should be?

Thanks softus for taking an interest.

 

[Softus]

sorry i misread or understood your answer/s.
How should the plumbing be then going to the radiator?

Without going into an entire plumbing course, the fundamental point is one I thought we'd covered, being that (a) if you have TRVs everywhere then you need to have a bypass for the combi), and (b) it's bad practise to have a radiator as a bypass because it's too easy to forget and turn it off.

Where he has fitted TRV's on the return side (omni directional TRV's) how do you balance a rad with a trv where the lockshield should be?

You don't need to balance if you have TRVs, because they automatically shut off when the room is hot enough.

 

[timbalcombe]

cheers

 

[Fluffster]

How long ago was the boiler fitted.

Sounds like it should have been power flushed if you have black magnetite oozing out, if it was not done properly this invalidates your warranty and can lead to a whole host of problems.

I would suggest getting the system properly flushed now.

Pete

 

[timbalcombe]

oh dear like what?
How about changing all the rads?
System seems to work ok with one exception;
The bottom MIDDLE of some rads take a very long while to heat up to the same temperature as the top of the rads. This is how I discovered the leaking rads, by adjusting the what I thought were locksheilds (the valves are the same on both sides).
Now, we all know a plumber is going to charge about £300 for a powerflush. Could i not get a magnaflow installed for a £100 instead?

The reason it wasn't powerflushed (aside from the extra cost) is that it is an old system of pipes and the engineer didn't want to "blow holes" in existing pipe work etc.

Damn....

 

[Softus]

System seems to work ok with one exception;
The bottom MIDDLE of some rads take a very long while to heat up to the same temperature as the top of the rads.

Then the system is NOT working ok. This pattern of temperature distribution is classic for a sludged up radiator.

Could i not get a magnaflow installed for a £100 instead?

No. Drain and refill and flush and drain and flush and refill and drain and flush etc. until you get all the muck out. If you uncover latent leaks then you'll have to replace some rads. That's life.