Baffling central heating problem - solved?
Discussion
One for the plumbers here. Long story, but I need to share.
We live in a 3-storey terraced house. Back boiler in middle of ground floor (GF) goes up to hot water on 1st, header tanks in loft over 2nd with radiator pipes radiating (sorry...) out from under hot tank on 1st, so the GF radiator is fed by a pipes down from one in room above on 1st. The back boiler is very old, but serviced yearly and produces piping hot water all the time. I should add that the previous owner was a rather flaky kitchen/cabinet maker who rebuilt the house almost completely himself, so everything is a bit eccentric, and has a box built round it, which makes DIY a real pain.
Over a period of several years our single GF radiator got colder and colder. Nice youngish lad two doors down set up on his own as a plumber, and thinking it would be a fairly easy fault to rectify, we decided to get him in to do the work. Over a period of several separate visits last autumn he first determined it didn't need bleeding, it wasn't full of sludge, in fact the water was very clean in the system, and that there appeared to be no airlocks.
It became clear that the problem was not the radiator but the system, as any single rad could be made to heat up, but not all at once. Next he tried replacing the pump, which was as old as the hills. No joy. I should add that he flatly refused to charge for labour for things that didn't work, bless him.
At this point we lifted some floorboards and established that the entire system (once the water got to the 1st floor) was plumbed with very thin 'microbore' piping, even where several pipes together ran in parallel. He came to the conclusion that these may have got less efficient over time and that the physical drag of pumping water round two storeys through microbore pipe was just not viable. Microbore was apparently a fad which has passed and should only ever be used to attach rads to a central larger distribution pipe.
I might add that he kept consulting his old lecturer from college, who backed his thought process up at each stage. We came to the conclusion that the only way forward was to replumb the system with decent (15mm?) diameter pipework. This began last Monday. Mrs Theboy & I took a few days each off to help move furniture/make coffee/ stop our bulldog licking his builder's crack (ewwww!), but when the job was done on Thurs AM it still didn't work.
I started putting Plumber on suicide watch at this point, as he seemed to be taking it very personally by this stage, and spent Friday trying to test the only original large diameter pipes (from boiler to 1st floor) for blockages but they were fine.
He came in this AM - we couldn't be there - and decided off his own bat to pull all the wood panelling
around the boiler, and has just rung to say he's found an isolation valve that (in his words) "some f***ing idiot" had installed BETWEEN the boiler and the pump, turned almost completely off, then panelled over the top of in such away that you couldn't even tell it was there, let alone adjust it.
HOPEFULLY, when he puts everything back together, the system should now work. Can any plumbers tell me why there would be a valve there, why it would be almost off, and why anyone would put it somewhere completely inaccessible? And more crucially if they would have thought to look for one there.
We live in a 3-storey terraced house. Back boiler in middle of ground floor (GF) goes up to hot water on 1st, header tanks in loft over 2nd with radiator pipes radiating (sorry...) out from under hot tank on 1st, so the GF radiator is fed by a pipes down from one in room above on 1st. The back boiler is very old, but serviced yearly and produces piping hot water all the time. I should add that the previous owner was a rather flaky kitchen/cabinet maker who rebuilt the house almost completely himself, so everything is a bit eccentric, and has a box built round it, which makes DIY a real pain.
Over a period of several years our single GF radiator got colder and colder. Nice youngish lad two doors down set up on his own as a plumber, and thinking it would be a fairly easy fault to rectify, we decided to get him in to do the work. Over a period of several separate visits last autumn he first determined it didn't need bleeding, it wasn't full of sludge, in fact the water was very clean in the system, and that there appeared to be no airlocks.
It became clear that the problem was not the radiator but the system, as any single rad could be made to heat up, but not all at once. Next he tried replacing the pump, which was as old as the hills. No joy. I should add that he flatly refused to charge for labour for things that didn't work, bless him.
At this point we lifted some floorboards and established that the entire system (once the water got to the 1st floor) was plumbed with very thin 'microbore' piping, even where several pipes together ran in parallel. He came to the conclusion that these may have got less efficient over time and that the physical drag of pumping water round two storeys through microbore pipe was just not viable. Microbore was apparently a fad which has passed and should only ever be used to attach rads to a central larger distribution pipe.
I might add that he kept consulting his old lecturer from college, who backed his thought process up at each stage. We came to the conclusion that the only way forward was to replumb the system with decent (15mm?) diameter pipework. This began last Monday. Mrs Theboy & I took a few days each off to help move furniture/make coffee/ stop our bulldog licking his builder's crack (ewwww!), but when the job was done on Thurs AM it still didn't work.
I started putting Plumber on suicide watch at this point, as he seemed to be taking it very personally by this stage, and spent Friday trying to test the only original large diameter pipes (from boiler to 1st floor) for blockages but they were fine.
He came in this AM - we couldn't be there - and decided off his own bat to pull all the wood panelling
around the boiler, and has just rung to say he's found an isolation valve that (in his words) "some f***ing idiot" had installed BETWEEN the boiler and the pump, turned almost completely off, then panelled over the top of in such away that you couldn't even tell it was there, let alone adjust it. HOPEFULLY, when he puts everything back together, the system should now work. Can any plumbers tell me why there would be a valve there, why it would be almost off, and why anyone would put it somewhere completely inaccessible? And more crucially if they would have thought to look for one there.
Lol.
Nothing to add really other than my system in microbore fed from a combi and it works absolutely fine. It does seem somewhat counterintuituve to use such a small bore pipe though.
Out of interest - any plumbers on here know what the reason for using microbore was, back in the day?
Oh and you can empty our your heating system (something I've done several times recently) and the water can be clear/clean looking. The rads can still be full of pure black sheeite though.
Nothing to add really other than my system in microbore fed from a combi and it works absolutely fine. It does seem somewhat counterintuituve to use such a small bore pipe though.
Out of interest - any plumbers on here know what the reason for using microbore was, back in the day?
Oh and you can empty our your heating system (something I've done several times recently) and the water can be clear/clean looking. The rads can still be full of pure black sheeite though.
Johnnytheboy said:
Can any plumbers tell me why there would be a valve there, why it would be almost off, and why anyone would put it somewhere completely inaccessible? And more crucially if they would have thought to look for one there.
They're quite common in gravity hot water systems to to prevent to upstairs radiators from heating up in the summer, when the boiler is being used for hot water only.Or it could have just been there to make changing the pump easier.
Obviously guess work why it was shut off - did you buy the house during summer? Or perhaps it had been closed down to linit the flow through the rads and had gradually become more blocked over time?
dave_s13 said:
Lol.
Nothing to add really other than my system in microbore fed from a combi and it works absolutely fine. It does seem somewhat counterintuituve to use such a small bore pipe though.
Out of interest - any plumbers on here know what the reason for using microbore was, back in the day?
Oh and you can empty our your heating system (something I've done several times recently) and the water can be clear/clean looking. The rads can still be full of pure black sheeite though.
Microbore can be very efficient and is commonly found in a lot of new build houses. There is not as much water in a microbore (8/ 10mm) pipe as there would be in a 15mm pipe. Therefore, the microbore pipe heats up quicker. It can also be easier to put in, as slight bends can be done by hand and it takes up less room.Nothing to add really other than my system in microbore fed from a combi and it works absolutely fine. It does seem somewhat counterintuituve to use such a small bore pipe though.
Out of interest - any plumbers on here know what the reason for using microbore was, back in the day?
Oh and you can empty our your heating system (something I've done several times recently) and the water can be clear/clean looking. The rads can still be full of pure black sheeite though.
You normally have larger bore pipes (22mm) from the boiler/ pump to manifolds. It is then reduced down to microbore from these manifolds.
On the disadvantages, microbore will clog up a lot easier if your system becomes sludged up and tend to stop working. The pump also has the added resistance of pumping around such a small bore pipe.
It has it's for's and against's.
Johnnytheboy said:
...found an isolation valve that (in his words) "some f***ing idiot" had installed BETWEEN the boiler and the pump, turned almost completely off, then panelled over the top of in such away that you couldn't even tell it was there, let alone adjust it.
I knew you'd find it eventually 
There's another one on the return pipe too. But you'll have to look harder for that one..
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