Hi
Trying to fix an issue found after hot summer break (for the boiler...)
Glow-Worm Back Boiler - Central-Heating side (pumped) works perfect.
Hot-Water Circuit (gravity) stays cold.
Boiler is on ground floor, indirect cylinder on first floor and F&E Tank in the attic.
Usual flush/refill (carried out several times) doe does not fix issue.
(1) Tried flush/refill from draincock on lowest Raditor
(2) Tried flush/refill from draincock on Cylinder Return (fitted closer to the Boiler)
(3) Tried flush/refill from F&E Tank, both Feed comming down and Vent pipe aching over
(4) Frustrated, I even cut the 28mm Flow pipe near the Cylinder and fluhsed out the coil.
I am now 100% certain I have NO BLOCKAGE in the HW Circuit. Using mains water, I eliminated every path in the HW Circuit that could have water under normal circumstances.
Closest I came to getting HW to rise up from the boiler was having slow speed mains water refilling the circuit from the draincock on the Retun pipe which is fitted near the Boiler. This way the Boiler continues to run a little longer before 'ketteling' out (with boiler Stat set to max). After few attempts like this I could get boiling water to vent/disscharge all the way up into the F&E Tank. Whist this is happening cylinder FLOW pipe (upper pipe) gets piping hot right up to the cylinder wall. You'd think soon the RETURN pipe (lower pipe) would get hot too and so begin the 'gravity hot water' cycle... but for me thats asking for too much.
As soon as I remove the slow re-fill (and close off the draincock on the Return) all pipes start getting cold except some of the Flow pipe near the Boiler. Boiler goes back to long breaks between firing and when it does fire up it lasts 40 seconds before it kettels off.
Some observations:
- Coil flush could be seen pushing water thru coil, out the cylinder, down the Return, into the Boiler, up the Flow and out the other cut-end.
- F&E Tank functioning perfectly for what it is designed.
- There are no valves in the Hot Water Circuit, just a pump in the Central Heating Cuitcuit.
- Central Heating works perfectly despite all this.
- Just cannot reason why the Boiler staying on much much longer for Central Heating able to heat up the Hot Water circuit.
- I am well aware not to expect the Garvity system to produce instant results so have allowed plenty of time into this.
- Would have thought refills using mains water would overcome any air locks.
Please help identify why HW will not circulate in the Hot Water circuit.
Is there any thing in the Boiler that may have stopped working?
Not keen on 'over-boiling' the Boiler method, not sure what it will achive that could not be helped by all actions already taken above.
Thanks in advance for your help and pointers in the right direction.
Glanmor
Trying to fix an issue found after hot summer break (for the boiler...)
Glow-Worm Back Boiler - Central-Heating side (pumped) works perfect.
Hot-Water Circuit (gravity) stays cold.
Boiler is on ground floor, indirect cylinder on first floor and F&E Tank in the attic.
Usual flush/refill (carried out several times) doe does not fix issue.
(1) Tried flush/refill from draincock on lowest Raditor
(2) Tried flush/refill from draincock on Cylinder Return (fitted closer to the Boiler)
(3) Tried flush/refill from F&E Tank, both Feed comming down and Vent pipe aching over
(4) Frustrated, I even cut the 28mm Flow pipe near the Cylinder and fluhsed out the coil.
I am now 100% certain I have NO BLOCKAGE in the HW Circuit. Using mains water, I eliminated every path in the HW Circuit that could have water under normal circumstances.
Closest I came to getting HW to rise up from the boiler was having slow speed mains water refilling the circuit from the draincock on the Retun pipe which is fitted near the Boiler. This way the Boiler continues to run a little longer before 'ketteling' out (with boiler Stat set to max). After few attempts like this I could get boiling water to vent/disscharge all the way up into the F&E Tank. Whist this is happening cylinder FLOW pipe (upper pipe) gets piping hot right up to the cylinder wall. You'd think soon the RETURN pipe (lower pipe) would get hot too and so begin the 'gravity hot water' cycle... but for me thats asking for too much.
As soon as I remove the slow re-fill (and close off the draincock on the Return) all pipes start getting cold except some of the Flow pipe near the Boiler. Boiler goes back to long breaks between firing and when it does fire up it lasts 40 seconds before it kettels off.
Some observations:
- Coil flush could be seen pushing water thru coil, out the cylinder, down the Return, into the Boiler, up the Flow and out the other cut-end.
- F&E Tank functioning perfectly for what it is designed.
- There are no valves in the Hot Water Circuit, just a pump in the Central Heating Cuitcuit.
- Central Heating works perfectly despite all this.
- Just cannot reason why the Boiler staying on much much longer for Central Heating able to heat up the Hot Water circuit.
- I am well aware not to expect the Garvity system to produce instant results so have allowed plenty of time into this.
- Would have thought refills using mains water would overcome any air locks.
Please help identify why HW will not circulate in the Hot Water circuit.
Is there any thing in the Boiler that may have stopped working?
Not keen on 'over-boiling' the Boiler method, not sure what it will achive that could not be helped by all actions already taken above.
Thanks in advance for your help and pointers in the right direction.
Glanmor
