Query for Plumbing Experts

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TripMeUp

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Hi all,

I recently moved back into my “your typical semi-detached 3 bed house” after being elsewhere for 2 years….
First thing I noticed was Heating was not working so I ordered some kerosene and asked a friend to bleed the boiler….

So far so good, heating came on…

Thereafter I noticed that my hot water tank (typical copper one located upstairs in Hotpress) was not heating up even if Heating was on for up to 5 hours and more…
I checked Rads and they seemed hot so wondered what could be wrong???
This cycle continued and I think that one evening, even though timer clock was on, neither Rads or tank were hot….
But on majority of evenings, it has been hot Rads with no Hot water in tank…
Then lo and behold on Monday evening, I checked tank and it was Hot…!!
I didn’t change anything and checked yesterday evening and back to same story….no hot water, but Rads on…

What could be wrong?

Ps: The boiler has not been serviced in years (I know, I know..)

Please help!!
 
Hi and thanks..

But if it was an airlock, would it heat one day and not all the others?
If so, how do I repair as I am clueless on this stuff...

thanks
 
It can work it's way around the system for a few days after the system is refilled.

Make sure you keep all radiators bled.

They have always worked themselves out within a week for me. Not sure what you would do it it did.
 
But on majority of evenings, it has been hot Rads with no Hot water in tank…
Then lo and behold on Monday evening, I checked tank and it was Hot…!!
I didn’t change anything and checked yesterday evening and back to same story….no hot water, but Rads on…

Could there be a separate time clock that you haven't spotted?
Previous owners could have had it set to heat water on a Monday evening and off rest of week...
 
Firstly go to your cylinder and you will have two pipes that are 18" apart and enter the cylinder parallel. On the bottom of these two pipes you should see a valve, ensure that this valve is not closed. It should be left half open.

If this is open, it may be an airlock. To clear, shut down (1 side only) all rads that heat up, once you feel heat on those two pipes I mentioned earlier (this will tell you it is circulating) open rads again.
 
Hi

thanks to all for suggestions so far...will try them out...

Davy,

Had a look in tank and this is what I see when looking into Hot press at very bottom of tank level: (Heat currently on)
From left, I see a pipe on its own which goes into tank at bottom (it's cold to touch)
Around the center of the press, I see a pipe coming down which links into bottom of tank and also branches off to a small red tank (immersion?)
Another pipe beside this comes up out of tank and is closed from going upwards (the pipe is discontinued) at one point and then goes downstairs (it's hot to touch).
This pipe has a valve (tap) which is closed tight to the left...
To the side wall is 2 pipes with one just going downstairs and the other also going downstairs but also going into the top of the tank (both cold to the touch)

The valve mentioned is the only valve at the bottom of the tank although there are others at the shelf level above the tank...
Does all this sound right to you and is this the valve you are referring to or is it another one?

thanks again..
 
From the sounds of it you have a sealed system. That red tank is an expansion vessel.
Do you have a gauge on the heating anywhere, on boiler or in hotpress?

You have four pipes directly connected to cylinder?

The pipe on very top, is hot water to taps, the pipe entering bottom left is cold water to replace used hot water. the two other pipes are from the heating. these are what I am referring to.

Is the valve fully opened? (turning anti-clockwise) if so can you close it freely? (turn it clockwise)

You say the top pipe is hot, as hot as the pipes entering bottom of rads? is the bottom pipe warm/cold?
 
Why not get your oil boiler serviced, most good servicemen will look at this issue for you while there. (instead of..i know..i know...)
Will save you money in the long run....

Diego has a point also, you may have motorised valves (it the dhw water one is faulty, hence hot rads and no hot water) not fair to just discount the guy like that, he has a valid point and may be correct.

Davy, surely if the person in question, closes the isolator (assuming there is one) to the ch rads, and allows the boiler/pump to act on cylinder alone this should easily confirm an airlock, or as you suggest the gate valve closed or stuck even (boiler will hit hi-limit pretty quick!) and if it is an airlock may have a chance of pushing it out to the boiler (where hopefully there is an auto-air vent, but then being Ireland maybe this is too much to hope for!)

Hmm Diego, a familiar name...oftec 'CERTIFIED' recently maybe!!
 
Check for faulty zone valves and their individual thermostats. If fitted these may be acting up and working irregularly.
 


Yes, these things are possible.

however it is best to start as simple as possible as most people lack any sort of technical knowledge of their heating systems. It has been established, that it is a sealed system of some type and the flow is getting hot, it may be a partically opened zone valve or balancing valve or blockage.

OP have you room stats in your home and can you have the boiler on just to heat the hot water?
 
Hi DavyJones and thanks..


“From the sounds of it you have a sealed system. That red tank is an expansion vessel. Do you have a gauge on the heating anywhere, on boiler or in hotpress?”

There is no gauge inside, there is one thermostat on the downstairs hall wall but I am sure there is a gauge of some sort on the boiler (I remember seeing it previously)

”You have four pipes directly connected to cylinder?” Yes think so

”The pipe on very top, is hot water to taps, the pipe entering bottom left is cold water to replace used hot water. the two other pipes are from the heating. these are what I am referring to.
Is the valve fully opened? (turning anti-clockwise) if so can you close it freely? (turn it clockwise)”

The valve I mentioned previously in my first reply to you Davy

{ “Another pipe beside this comes up out of tank and is closed from going upwards (the pipe is discontinued) at one point and then goes downstairs (it's hot to touch). This pipe has a valve (tap) which is closed tight to the left”}

is attached to the pipe that comes up out of the centre of the bottom of the tank.
This valve is at the very bottom of the press.

The 2 other pipes to the side have a valve (I think) higher up in the Hot Press, so is this the one you want me to check to see if it is fully turned to the left (anti-clockwise ??

”You say the top pipe is hot, as hot as the pipes entering bottom of rads? is the bottom pipe warm/cold? “

As far as I can remember all other pipes were cold to touch...

Does this shed any further light on the issue??



"however it is best to start as simple as possible as most people lack any sort of technical knowledge of their heating systems"


Totally correct in my case!!


"OP have you room stats in your home" No, just the one stat referred above that is in hallway
"and can you have the boiler on just to heat the hot water?"
Not that I know (but that doesn't mean much!!)....I used to just turn off each Rad when I lived there previously...


Again thanks to all
 
That valve that is "closed tight to the left", does it move freely to the right?

What happens when you turn stat on wall down to 0?
 
Hi Davy,
Yes that valve can be moved freely to the right if I try to turn it....

Havent tried turning stat to 0 previously, but this morning in an effort to see if airlock was the problem, I did the following..

Had heating off.
Went out to boiler and turned the temp upto close to 85 from around 65...
Turned each rad off individually...
Turned on Heating at wall clock and waited..figured that if all Rads were off, then only place hot water could go would be into tank and thus would clear airlock if any.. does this sound right?

Anyway, hot tank didn't heat up at all...so what that means I don't know...

thanks again for suggestions...
 
Hey all

Had another go at above post's process re eliminating airlock and guess what....all seems to be working ok (for now anyway) !! Fingers crossed..

thanks to all for their input..especially Davy...
 
When you turn your stat right down, it should shut dowm all the rads, so no need to turn off each rad.

Glad you got it sorted but feel there maybe an other reason for it, namely a partly closed/faulty valve or a partically blocked pipe.
 
hi davy

When you say turn the stat down, I presume you mean the one in my hallway?
If so, when I set this at zero, will the hot water tank still be heated?

I think you might be right about something else being wrong as it has been behaving a bit erractically..!!

thanks
 
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