4 bed house with a traditional open system, F&E header tank, 160 litre storage cylinder, Y plan pumped system.
Three years ago we replaced our ageing and leaking cast-iron core boiler with a Glow Worm Flexicon 24HX, which has certainly reduced our gas bills by around 30%. The CH works really well, there's no doubt that the boiler is fast and efficient and doing a good job.
However the supply of hot water from the cylinder is never adequate for a good hot shower or two, compared to when we had the old system (separate motorised valves on CH and HW) which gave us lashings of really hot water. At the same time as he fitted the boiler our plumber also fitted a new, bigger 160 litre copper cylinder with two coils; the upper for the boiler and a lower smaller coil for the solar panel. The upper coil is supposed to be "half hour rated". I can't see the maker's label on the cylinder.
We have replaced the wax cartridge in the shower and we have had the boiler checked by an engineer and it is performing fine. However he pointed out that when running the HW alone after two morning showers (i.e. cool cylinder), the water temp was going up to around 83c but the return temperature was also high and consequently the boiler was ramping down quite soon and switching off. This tells me the coil isn't extracting enough heat from the HW circuit, even after two showers.
We've had the plumber back and he says that's the best performance we can expect from the system and he can't see anything wrong. However we simply can't believe that such a good boiler can produce such miserable tepid water. This morning I have just endured a warm (rather than hot) shower and now as I sit typing this I hear the boiler fire up every 3-4 minutes then immediately ramp down again and stop within 30 seconds. The HW temperature at the tap is 53 degrees right now measured with a lab thermometer. The cylinder 'stat is set at 60 and seems to work OK, it clicks in the right places.
Now here's the rub: when he first fitted the new cylinder I was able to hear water trickling inside it for a couple of weeks. He assured me that it was nothing to worry about but I became convinced there was air in the coil - difficult to believe as it all slopes upwards but anyway he came back and installed an auto-bleed on the flow side of the coil, which does emit gas when you unscrew the little cap. The system is filled with Fernox and we do get a small amount of gas inside the bathroom towel rail but no more than a few seconds of hiss when I bleed it. The water that comes out is clear and clean.
My other concern when he fitted the new cylinder was that he piped it in 15mm but again, he assures me this shouldn't matter.
Our plumber is a serious, experienced guy with a long-established family business who we've known for years and who did very good work in our previous house so we know he's good. It's not like he's some kind of cowboy or fly-by-night!
Oh - one more point: after three years the Y plan valve is clonking sometimes when it moves so I'm guessing the rubber ball inside needs replacing. We have soft water so limescale isn't a problem.
My question: is it possible that the cylinder is actually faulty and somehow the coil is leaking? If so, what other symptoms could we expect to see?
Second question: could the clonking Y plan valve be allowing leakage fo hot water from the HW circuit into the CH? I've tried running the system from cold on HW only but there's no evidence of warming of the output pipe to the CH.
Any suggestions would be gratefully accepted before we get the man back; he is as mystified as we are. I do intend to ask him to change the Y plan valve.
Three years ago we replaced our ageing and leaking cast-iron core boiler with a Glow Worm Flexicon 24HX, which has certainly reduced our gas bills by around 30%. The CH works really well, there's no doubt that the boiler is fast and efficient and doing a good job.
However the supply of hot water from the cylinder is never adequate for a good hot shower or two, compared to when we had the old system (separate motorised valves on CH and HW) which gave us lashings of really hot water. At the same time as he fitted the boiler our plumber also fitted a new, bigger 160 litre copper cylinder with two coils; the upper for the boiler and a lower smaller coil for the solar panel. The upper coil is supposed to be "half hour rated". I can't see the maker's label on the cylinder.
We have replaced the wax cartridge in the shower and we have had the boiler checked by an engineer and it is performing fine. However he pointed out that when running the HW alone after two morning showers (i.e. cool cylinder), the water temp was going up to around 83c but the return temperature was also high and consequently the boiler was ramping down quite soon and switching off. This tells me the coil isn't extracting enough heat from the HW circuit, even after two showers.
We've had the plumber back and he says that's the best performance we can expect from the system and he can't see anything wrong. However we simply can't believe that such a good boiler can produce such miserable tepid water. This morning I have just endured a warm (rather than hot) shower and now as I sit typing this I hear the boiler fire up every 3-4 minutes then immediately ramp down again and stop within 30 seconds. The HW temperature at the tap is 53 degrees right now measured with a lab thermometer. The cylinder 'stat is set at 60 and seems to work OK, it clicks in the right places.
Now here's the rub: when he first fitted the new cylinder I was able to hear water trickling inside it for a couple of weeks. He assured me that it was nothing to worry about but I became convinced there was air in the coil - difficult to believe as it all slopes upwards but anyway he came back and installed an auto-bleed on the flow side of the coil, which does emit gas when you unscrew the little cap. The system is filled with Fernox and we do get a small amount of gas inside the bathroom towel rail but no more than a few seconds of hiss when I bleed it. The water that comes out is clear and clean.
My other concern when he fitted the new cylinder was that he piped it in 15mm but again, he assures me this shouldn't matter.
Our plumber is a serious, experienced guy with a long-established family business who we've known for years and who did very good work in our previous house so we know he's good. It's not like he's some kind of cowboy or fly-by-night!
Oh - one more point: after three years the Y plan valve is clonking sometimes when it moves so I'm guessing the rubber ball inside needs replacing. We have soft water so limescale isn't a problem.
My question: is it possible that the cylinder is actually faulty and somehow the coil is leaking? If so, what other symptoms could we expect to see?
Second question: could the clonking Y plan valve be allowing leakage fo hot water from the HW circuit into the CH? I've tried running the system from cold on HW only but there's no evidence of warming of the output pipe to the CH.
Any suggestions would be gratefully accepted before we get the man back; he is as mystified as we are. I do intend to ask him to change the Y plan valve.
