John P
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| posted on 4/10/09 at 09:55 AM |
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Any heating Engineers out there?
Earlier this year we had our old boiler replaced with a new Worcester unit (conventional, not combi) which was fitted with all new controls.
Just before we went away for a week I was up in the loft and noticed the header tank was fairly hot and it looked as though hot water was being forced
out of the vent pipe.
Because we were going away I simply turned the programmer settings to off but now we're back home although the heating came back on OK it took
around 3-hours to get any hot water.
I'm not totally convinced it's anything to do with the new boiler installation but what else could be the problem?
For reference it's a 3-bedroom bungalow with the heating pipes under the floor and has two 2-way motorised valves, a room stat and cylinder
stat.
John.
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eccsmk
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| posted on 4/10/09 at 10:09 AM |
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for it to pump over into the feed and expansion tank it must have a restriction in the pipework somewhere
in your case it could possibly be a sticking motorised valve
there will be a lever on both valves so you can manually open them
it might be worth manually opening each valve to check they are not sticking,
also if you pop your heating on and feel the pipework before and after the valve to make sure they are letting the water through
sorry for the rambling but im popping toa job so had to write in a hurry
HTH
[Edited on 4/10/09 by eccsmk]
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mookaloid
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| posted on 4/10/09 at 10:24 AM |
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I had that problem in my last house. It needed a new cylinder - the coils inside failed which pushed hot water up and into the header tank and out of
the overflow.
"That thing you're thinking - it wont be that."
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craig_007
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| posted on 4/10/09 at 10:39 AM |
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Try reducing the pump speed.If it's on 3 try 2 and see how your getting on
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John P
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| posted on 4/10/09 at 10:50 AM |
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I was wondering about the hot cylinder but can't quite work out why it would happen.
I assume the hot water inside the tank is at the same pressure as the cold and expansion tanks since these are virtually at the same level in the
loft.
As result there wouldn't be much pressure difference between the hot tank and the water within the heating coils although I suppose that once
there's a hole in the coil water from the tank could get into the heating circuit and cause it to overflow.
If it helps I'm also having
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liam.mccaffrey
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| posted on 4/10/09 at 12:16 PM |
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Engineers don't install or repair domestic heating systems.
Good luck getting your problem sorted
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MautoK
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| posted on 4/10/09 at 12:37 PM |
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+1 
He's whittling on a piece of wood. I got a feeling that when he stops whittling, something's gonna happen. (OUATITW/Cheyenne)
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Bigheppy
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| posted on 4/10/09 at 03:19 PM |
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The first thing to do is to have a look at the installation manual there will be a picture of how the pump, valves, cold feed and expansion pipes
should be fitted. The system should be close coupled, the cold feed should be within 6" of the expansion pipe and be closest to the circulating
pump if the pump is fitted to the flow pipe. If fitted correctly there should be almost equal pressure on both pipes so there is no pumping over. A
small amount of hot water could be forced out through the expansion pipe when the diverter valves close even this can be eliminated by fitting an
'elephant tube' basically this is a large diameter tube fitted vertically in the expansion pipe above the water level so any sudden surge
fills the large tube rather than going into the header tank. The reason for stopping the 'pumping over' is that each time it occours it
puts oxygen back into the water, when this enters the system it can cause corrosion of the steel radiators and a build up of sludge which makes the
system less efficient, the radiators would also need bleeding more often.
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John P
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| posted on 4/10/09 at 05:47 PM |
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Sorry if I offended anyone by refering to Heating Engineers.
I'm a Mechanical Engineer myself and used to be very protective of the term but having been made redundant at the age of 60 and found nobody is
even vaguely interested in my skills and experience I'm a little less than committed to engineering anymore.
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liam.mccaffrey
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| posted on 4/10/09 at 07:01 PM |
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My sympathies Pete. I have had the privilege of working for a number of particularly good engineers and I think that generally the skills are not
understood or appreciated!
I'm going after IEng status at the moment and get a little hot under the collar sometimes when the term get used inappropriately.
The attitude in the US is so different!!
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