hot water in central heating header tank

[iwol]

hi just seen my overflow running from the central heating header tank,when i went in the loft i found hot water entering the tank from the pipe just above the tank ,could anyone please tell me what causes this please ps my radiators are getting hot ok cheers

 

[sonray ltd]

its called pump over.

useally caused by- pump speed to high, sludge in system, cold feed blocked, faulty boiler stat.

have you done any work on the system lately ?
whats the condition of the water in the bottom of the tank ?
how old is the system ?

 

[iwol]

thanks for reply,just turned pump down to no2,it was on three,still a bit of water going into header but not like it was ,havent done any work on the system for a while and water in tank doesnt look too bad should this tank be completely cold all the time cheers

 

[sonray ltd]

yes completly cold.
check the cold feed from the tank to the system is the pipe cold or hot ?
if its hot after about a ft upwards poss a blocked cold feed.

one way to check if to drain some from the lowest draincock and if the ballvalve opens and refills you know its clear if the system drains and the tank is full the pipes blocked.

or run a magnet down the pipe near where it joins the system if it trys to stick its got a blockage there.

 

[iwol]

thanks sonray checking now

seems turning pump to no2 may have worked ,theres no water going into the header now, and the pipe you mentioned is hot all the way down to the ceiling,just double checked water in tank and it has a rusty tinge to it ,but only just tinged, is this normal, and by the way thank you very much for your help and advice

 

[sonray ltd]

n02 is normal for a general house.
probably due to the age its not that bad if not been touched for yrs.
but the brown will be rust and long term is not good but if your not forever blowing rads etc don't loose sleep over it.

>hot all the way down to the ceiling.

what do you mean ? the ceiling of the room below i take it.
it should really be cold the vent pipe will be hot quite away up but the feed should only be hot about a ft from where it joins the system.

(the pipe may just be hot cause the tanks got hot water in it. let it settle then check tomorrow)

keep your eye on it, if the top of the upstairs rads start going cold.
you know its not letting water into system

 

[iwol]

by the way theres a pipe that is teed off from the pump output before it gets to the diverter valve that has a valve on that looks like it goes to the return of the water/heating ,what is this and should it be open/closed cheers

 

[sonray ltd]

thats a bypass loop.
have you any rads with trvs fitted (thermostatic rad valves) ?

 

[iwol]

the hot pipe i mention comes out the bottom of the header tank and goes down throught the ceiling

five with trvs and three without

 

[sonray ltd]

the hot pipe i mention comes out the bottom of the header tank and goes down throught the ceiling

let it settle as the tank has had hot water in, so tomorrow when it gos cold and the system is running that pipe should stay cool.

 

[iwol]

thanks does the valve need to be open what does it do please

 

[sonray ltd]

thanks does the valve need to be open what does it do please

depends does the rads have trv's fitted if yes the the valve should be open about 1/4 - 1/2 max turn

if no trv's shut it or leave at 1/4 turn

its to take the flow to the when the trv's start closing when rooms up to temp.

 

[iwol]

thanks once again sonray your a gent, going now with peaceful mind hopefully, thank you very much