I wouldn't go pressurised, there are pros and cons of pressurised vs F/E tank if choosing for a new installation, but there'll already be F/E tank in the loft. I wouldn't go combi either, why not put in a heat-only boiler and modernise the layout and controls.
Stainless pipes potential for leaks going from gravity to combi
- Thread starter mrbrunes
- Start date
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Or IG combi fitted as OV
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The reason for leaning towards a combi is:
- current HW flow rate from cylinder is poor with the bathroom being only down from the cold cistern in the loft
- useful to have the bathroom tap serving up mains rather than pigeon water from a cistern
- cylinder taking up lots of space that could be used for a shower cubicle
- seems wasteful to keep heating a whole cylinder of HW for a single person
Pardon my ignorance but what's the diff between "heat only and non-pressure / f+e" and Open Vent ?
(I've got a IG Xclusiv combi which has been a great successor to my old WB Highflow 400 which, though it had excellent HW flow, went v unreliable near the end)
- current HW flow rate from cylinder is poor with the bathroom being only down from the cold cistern in the loft
- useful to have the bathroom tap serving up mains rather than pigeon water from a cistern
- cylinder taking up lots of space that could be used for a shower cubicle
- seems wasteful to keep heating a whole cylinder of HW for a single person
Pardon my ignorance but what's the diff between "heat only and non-pressure / f+e" and Open Vent ?
(I've got a IG Xclusiv combi which has been a great successor to my old WB Highflow 400 which, though it had excellent HW flow, went v unreliable near the end)
It's to do with whether the system is pressurised or whether you have a small header cistern in the loft.
You can't run the Xclusive open vent
nice view of an annulus there
There is absolutely no reason not to fit a combi if that is your want. OP might want to utilise the space that would be better used. As far as controls are concerned, why should combi be the boiler that misses on controllability. I have a combi that is controlled to a high degree.
Have done it several times to system that was ancient and recently to a system that has SS plumbing.
Did that to system that was plumbed with truewld pipe also that went from OV to sealed system. In fact Ian did a pcb change on the boiler during lockdown.
I quite agree, as long as he has considered the pros and cons of each option.
I wasn't suggesting a combi is less controllable, I just meant that for a system 27 years old, possibly gravity HW, pumped CH, the controls probably need updating, whether heat-only, system or combi. As the new boiler will be in a different location from the existing, there'll be some pipe mods for any boiler, so it might be appropriate to move the pump (if separate as in heat-only)
I think I've researched the pros and cons so am not blindly going for a combi.
The current controls are an ancient timer Sangamo 410 F4 with no thermostat (room or HW) with gravity HW and pumped CH.
Even if I can't persuade my mother for a new boiler (one part depends on how compelling the gas prices make the payback) then she would consider a new programmable controller to optimise the efficiency for the 65% back boiler.
The ideal would be a "simple" one with thermostats for heating and HW that would also work with a combi (or other boiler) in future.
The anxiety around any new "gadgets" is not to be underestimated - and that even extends to staying somewhere nice while any work is done!
I've had Drayton Wiser and Tado and they have had issues which she would not be abe to cope with (even though I normally favour solutions that can be remotely controlled).
Tx again for all the info.
The current controls are an ancient timer Sangamo 410 F4 with no thermostat (room or HW) with gravity HW and pumped CH.
Even if I can't persuade my mother for a new boiler (one part depends on how compelling the gas prices make the payback) then she would consider a new programmable controller to optimise the efficiency for the 65% back boiler.
The ideal would be a "simple" one with thermostats for heating and HW that would also work with a combi (or other boiler) in future.
The anxiety around any new "gadgets" is not to be underestimated - and that even extends to staying somewhere nice while any work is done!
I've had Drayton Wiser and Tado and they have had issues which she would not be abe to cope with (even though I normally favour solutions that can be remotely controlled).
Tx again for all the info.
Sounds to me like you need to let a heating engineer look at it. If you go for combi the HW outlet on the combi will need connecting to the HW outlet pipe from the cylinder somewhere (not necessarily near the cylinder), likewise for the CH outlet into the heating circuit.
With heat-only or system need to connect to the cylinder primary and to the heating circuit (after a diverter valve).
How straightforward any of that is depends very much on the house layout.
Gas Safe were very helpful and confirmed that this was nothing to do with Gas Safe regs.
They also supplied me with Tech Bulletin 091 "Decommision part of a gas appliance" which Baxi advised me needed to be followed confirming that it is possible to retain a back boiler gas fire whilst decommissioning the back boiler, contrary to what several installers have said.
I completely appreciate that installers may have their installation preferences, but they appear to quote regs or manufacturers as being the source behind their advice when this is not the case when I have checked. Quite worrying.
Good chance the HW primary is gravity fed
system boiler will need fully pumped primaries to cylinder and radiators.
While it is a possibility, but often the cylinder is not insulated and indirect coil resistance would be low to aid circulation.
Connect it to fully pumped system, boiler will be cycling a lot as it will be low content and heatup would be rapid. So cylinder change would be in the cards too to make good use of boiler heat output as often cylinders have high input indirect coils
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