Blocked hot water system

[Theeagle]

I have been told that my indirect hot water system is blocked. I have been
quoted £460 + VAT to have it pressure flushed. Is there anything I can try myself and is this a good price. How can you locate the blockage?

Many thanks in advance for any help.

Dave

 

[matt1e]

Hi Dave
It would help If you described the problems you are having first

Matt

 

[Theeagle]

Sorry!
I am not getting any hot water and the towel rail in the bathroom is not getting hot. The central heating is working fine. It is a pumped system.
The engineer thought it was an air lock at first, but couldn't clear it.
Hope this helps

Dave

 

[matt1e]

Hi Dave
I'm persuming your central heating is ok
Do you have any of these on your system if so 3 port or 2port

some photos of them and cylinder etc would be a help

 

[Theeagle]

Yes I do have one of those. It's a 3 position Honeywell diverter valve which according to the engineer is working ok. The central heating is working fine.
The hot water pipe from the diverter valve gets very hot!

Dave

 

[matt1e]

ok this is yours

a quick question for you
if you select hot water only on the controller does
a) the boiler fire ?
and
b) the radiators get hot?

 

[Theeagle]

That's the one. Yes the boiler does fire up and no the rads do not get hot.

Dave

 

[matt1e]

ok does selecting ch only fire the boiler and heat the rads?
if so then yes it does seem as though the valve is ok
I would have thought your problem would more likely to be an airlock though
do you know if your system is sealed or open vent?

 

[Theeagle]

Hi
Yes, with the central heating only on the boiler lights and the rads heat up.

Not sure about the sealed or open vent, how can I tell?
How do you clear an air lock in either case?

 

[Nige F]

Open vent system will have a small water tank in roof - like the cold water storage tank , but smaller There should be a air vent on the pipework near to the cylinder Set the lever control on the side of the box to manual over ride - both ch and water should get flow - because the paddle /ball inside the valve is held mid position .. Report back - I`m on standby in E. Sussex over the weekend PS try and locate the feed/ vent connections from the tank in roof to c/h system - test with a magnet for iron deposits - could be a blocked cold feed which a power flush won`t solve - probably a "sticky" about this somewhere on this site

 

[Theeagle]

Hi

It is an open vent system. I have checked the air vent by the hot water tank, ok and bled the towel rail also ok.
I have set the diverter valve to manual. The central heating rads are all hot, the towel rail is vaguely warm but no more, one pipe warmer than the other
The pipe leading to the top of the coil in the hot water cylinder is hot.
I have checked the pipes on the header tank and as far as I can tell they are clear.


Dave

 

[petit_pablo]

Is there a valve on the return pipe from the cylinder? Has this been checked to make sure its opened?

If the heating works fine then the blockage on the HW circuit cannot be in that big an area.

 

[Theeagle]

Valves are open. Think I'll start looking for blockages. May try flushing the system using the pipes to the towel rail. What do you think?

Dave

 

[matt1e]

Hi

It is an open vent system. I have checked the air vent by the hot water tank, ok and bled the towel rail also ok.
I have set the diverter valve to manual. The central heating rads are all hot, the towel rail is vaguely warm but no more, one pipe warmer than the other
The pipe leading to the top of the coil in the hot water cylinder is hot.
I have checked the pipes on the header tank and as far as I can tell they are clear.


Dave

Hi Dave there is water in the header tank too I persume?
also check for any manual valves on the cylinder pipe work as per petit_pablos' post above
some pics would be of help

 

[Theeagle]

Hi

There is water in the header tank. The valves are open, they shouldn't have changed as they are out of the
way and so nobody would think to close them, but I have checked them anyway!

Is a magnet they best way? Or is there an easier way?

Dave