Central heating water is Black!

[gsevans]

Hi all - Another project gets more complicated!

I have changed and moved some radiators around my place today and now have 2 issues:

1 - my inlet isolating valve to boiler is blocked
2 - system is full of black water

These issues are clearly connected and wanted to check with you kind folk on my assumptions and had a few questions, so:

Assumptions:

1 - i assume that the black water is due to erosion and that my magnetic filter may need replacing.
2 - this has caused the isolating valve to block.

Questions:

1 - If i have a magnetic filter do i still need inhibitor in the system?
2 - Do i need to flush the whole system with cleaner and replace inhibitor?
3 - Can i bypass the inlet isolation valve as a temporary measure without damaging the system?
4 - Is this something that should have been picked up by my boiler service that i had done last month?

 

[ianmcd]

Hi all - Another project gets more complicated!

I have changed and moved some radiators around my place today and now have 2 issues:

1 - my inlet isolating valve to boiler is blocked
2 - system is full of black water

These issues are clearly connected and wanted to check with you kind folk on my assumptions and had a few questions, so:

Assumptions:

1 - i assume that the black water is due to erosion and that my magnetic filter may need replacing.
2 - this has caused the isolating valve to block.

Questions:

1 - If i have a magnetic filter do i still need inhibitor in the system?
2 - Do i need to flush the whole system with cleaner and replace inhibitor?
3 - Can i bypass the inlet isolation valve as a temporary measure without damaging the system?
4 - Is this something that should have been picked up by my boiler service that i had done last month?

Try not to ask so many questions at once or you may get confused with the replies you receive.

Answer to your assumptions

1. The black water is Magnatite and yes caused by corrossion within the system but unlikely that your magnetic filter needs replacing you will need to find a way of agitating or dislodging the existing magnatite to enable your filter to catch it.

2. Possibly but not necesserally do the isolating valves have plastic levers ? if so more likely you have closed the valves and they are still closed as the plastic levers have stretched just remove the plastic and use a spanner to open the valve.

Answer to your questions

1. yes you still need inhibitor but you will have to clean the system water first.

2. yes power flush would be best but if just a chemical flush you will need to agitate the existing rads to free the magnatite into the water.

3. shouldnt be a problem but as said unlikely you will need to.

4.Nope not unless you mentioned circulation problems and the problems you have cannot be sorted by doing anything to the boiler.

 

[gsevans]

Thanks for the reply, just what i was after. Cheers!

 

[JohnD]

what sort of magnetic filter have you got, and how often have you been emptying out the accumulated sediment?

 

[gsevans]

It has never been cleaned out! we moved into a doer-upper 6 months ago and would guess that before me it was also never cleaned out!

Good point, it was not something i had thought about.

 

[JohnD]

best get on and do it then.

If you don't know the make, what colour is it?

have you got a feed and expansion tank in the loft, and is there a layer of fine silt in the bottom? (try not to stir it up) and has it got a lid?