Water in expansion tank always hot?

[abranscouk]

Afternoon All,

My Dad has just had his heating and hot water system (Micro bore) cleaned and flushed through, and every thing is working fine, other than the water in the expansion tank (loft) is now always very hot.

Since the cleaning of the system, we have turned the pump down to a low setting along with the boiler to compensate for a unclogged system, but still the tank gets very hot.

Any ideas?

Andy

 

[freeflow]

is water flowing out of the vent pipe when the pump is turned up? if thats so ,you have a problem with the layout of the feed and vent where it connects to the system. a system that is pumping over will sludge up very quickly.

sounds like that is why the system needed cleaning in the first place.

 

[JohnD]

Freeflow is right, but also:

I hope that a corrosion inhibitor, such as X100, was added when the system was refilled after cleaning.

If it had a lot of black sludge in it, it would be worth having a Magnaclean fitted as well (cleaning never gets it all out) as this traps circulating black material and prevents it forming future blockages.

If the F&E is very close to the cylinder or boiler, and directly above, there will be a little natural convection of warm water within the pipe.

 

[OvertonPlumber]

Oki firstly im surprised that anyone would actually flush a microbore system we and kamco advice is to avoid powerflushing microbore as the manifolds can rupture and you can send plugs of crap into all the wrong places.
THe best thing with microbore is a heavy dosing of x400 and a magnaclean fitted.
The pump on a microbore system always must be turned up high as all those iddy biddy pipes cause lots and lots or resistance and the circulator is there to overcome that.
I would take an educated guess that you have Trvs on most of your rads and no automatic bypass, essentially the only bypass your system has is the header tank loop hence why its getting hot.
Before long you will also get some nice semi tropical stuff growing on the surface of the header tank.
The simple solution is to remove the trv head on 1 big rad in the system.

 

[Agile]

Manifolds rupture? What is Keith thinking of?

If the rads are up to it then I would use a citric acid based chemical and add it to each rad in turn with a power flusher or just in the system.

I would then recommend that its converted to a sealed system if the boiler and rads can cope.

Tony

 

[simond]

Manifolds rupture, ha ha.

Kamco, like every other Powerflush machine, relies on water volume to clean the rads. A significant length of microbore significantly reduces the flow and thus the rads don't cleaned out properly. There is also the danger that muck dislodged from the relatively harmless radiator will then block the microbore return.

I would do as Agile suggests, or remove every rad individually and hose outside. Not if you have white carpets though......

 

[namsag]

If it is twin entry valves on your rads then you have been conned as you cannot power flush properly on a system like that as it just leaves all the carp at one end of the rad.
Never seen a manifold rupture