Advice needed : changing from Partly pumped to fully pumped S Plan

[Asif Qureshi]

Dear all,
I have the following setup at my house for past 15 years.
1: Oil fired 35W Firebird boiler with flue in Garage ground floor
2: Convection based HW system with non-pressurized Cylinder which is fed by attic cold water storage tank . Only a Pleger Thermo mechanical valve with mercury tube as flow control to cylinder HW coil.
3. Pump comes ON along with burner as CH is switched on / does not come on when only HW is switched on ( convection )
4. Apparently, the hot water cylinder, first floor, is too far away from boiler....
Added for advise ( pictures ) later

Plan : advice required for Conversion to fully pumped S-plan regarding :

1. Plan to use 3 Motorized valves e.g V4043H , one each at CH supply separately , upstairs & downstairs and one at HW supply
2. Do I need an automatic bypass valve like DU144 ? Where would I connect it
3. Do I need to Take out the mechanical Pleger thermo valve from the HW system at cylinder entry
4. Should I also replace the 15mm pipes afterwards with 22mm which are plumbed for only 24 Inch run close to HW cylinder , tapped off the 22mm coming from boiler
5. Any safety issues as the motorized valves can fail during their service life

ANY HELP WOULD BE HIGHLY APPRECIATED

 

[Asif Qureshi]

 

[Asif Qureshi]

 

[SimonG]

Cylinders not too far away. If it's recently fitted then I would say it's second hand and wasn't suitable for gravity primaries.

You need to find somebody, and not the one who did the pipework in the cylinder cupboard, to get the work done properly.

 

[Asif Qureshi]

Thanks Simon,
The cylinder and everything is not new. 15+ yrs old since I have been in the house.
The only work done during this time was done by a qualified plumber / gas fitter.
1. Cold water supply taken from mains instead of the overhead tank and now has mains pressure. ( No need for the second salamander pump)
2. Top overhead attic water tank gets riser supply the same way
3. Hot water supply needed a boost ( salamander pump) for upstairs shower and bathrooms and has a TMV-2 thermostat valve fitted to it before it gets pumped
In short, the hot water still comes from gravity cylinder
What do you mean " the hot water cylinder is not appropriate" it's definitely fitted by the builder when house was built in 1999 - 2000

 

[Jimmy18]

Your better off ripping out and replacing everything imho as your going to need major work done on zoning upstairs and downstairs separately anyway.

 

[Asif Qureshi]

Ant suggestions for modification of the system with minimal rip apart
how about installing three motorized 4043B zonal valves at the flow pipes right next to the boiler thus independently controlling the HW and two CH zones ??
Wire roomstats and cylinder stats and electrics can be sorted out no problem, its the plumbing part I need advice on

 

[Jimmy18]

How are you going to to that? You need to make major adjustments to cap off the legs that that go downstairs and tee in the returns etc. You may as well repipe and do it properly as by the look of your pipework it wouldn’t hurt

 

[Asif Qureshi]

Just want to point out here that the upstairs and down stairs CH circuit to radiators are completely separate as you can see next to the boiler , the CH pipe going upwards supple all the upstairs and the pipe 28mm going down to the ground is only for CH radiators for ground floor.