Trying to complete Heating /Diagram / Schema. Any comments ?

[Blaze]

Hi,

Been living in current house for 2 years (built 1960's). I posted a couple of weeks ago with my system setup, couple of replies, outlining some major changes needed. Basically, I have a Floor Standing Ideal Mexico 2 Boiler (works), on a GRAVITY Feed system (don't know why it was not upgraded when the new Boiler was installed in 93), with F&E Tank, Cold Water Storage in loft (vented), Indirect Hot Water Cylinder in Airing cupboard (with jacket built-on from factory so guessing this is reasonable heat return but I don't think boiler is up to it, one pipe central heating - nice to balance, but keeps the house very warm quite quick . All works, but in house of 5 people, 3 females i.e. lots of baths, about to have side extension built with shower room in downstairs w.c., have to wait for water and when the extension happens the window of opportunity changes.

Feel its the best time to upgrade if we are going to, even though economies of scale suggest it won't pay for itself for around 15-20 years ! and plan the following:-
Change CH piping from one pipe copper to plastic two pipe hep2o, 22mm runs with 15mm breaks to each rad.
Change boiler from floor standing in outside boiler room to System Boiler in Airing cupboard (550mm width so just enough space).
Update current loft tank with new and have old safely removed. Stop using F&E too.
Have System Boiler change system to fully pumped with some changing of the current pipes.
Have Gas Man move gas pipes upstairs.
Ask builder to prep up MDPE as a new cold mains (currently around a 15mm lead pipe) then ask Water board to connect to lift the flow a little.
Use Weather Compensation to manage heating.
Poss use additional controller if setting within Airing cupboard is a hassle.
Change rads (some smaller than current install which was compensating for one pipe flow) and place TRV on all.
Would the Bath - Tail Rail be on the DHW or CH pipes ?
Add Power Shower Pump (would do two showers. One in bath, one in downstairs w.c.).
May update HW Clylinder to ensure quick recovery as don't know history of current cylinder.

Should then have a new fully pumped system on two pipe CH, quick recovery Hot Water via HW Cylinder (not pressurised as it won't fit where I would like it to be installed and I think it is too much at this stage, space for new cylinder is limited to 550mm).

I've drawn a basic diagram / schema of where, in my head things would go. Does this look OK ?

Basic Key
A - Rising Mains
B - 50G Cold Water Tank
C - Cold Feed down to DHW
D - 170L Indirect DHW Cylinder with Immersion
E - Cylinder Feed
F - Cylinder Feed
G - CH Feed
H - CH Feed
I - External Weather Compensation sensor
J - DHW Feed
K - Cold Mains pressure feed
L - Shower Feed
M - Shower Feed
N - Cold Feed
O - Bath
P - 3 bar ? Pump
Q - Thermostatic Power Shower
R - Vent
S - New Rads, approx 13 with TRV
T - System Boiler 26 to 28kW
U - Shower Feed
V - Shower Feed
W - Gas
X - Rising mains to be updated to 25mm
Y - Loft - should tank be raised ?
Z - Cylinder thermostat


The system would be on W plan, providing DHW first, then CH but hoping System Boiler will manage via Weather Comp.

System Boiler Flue to side and condensation pipes would back onto bathroom.

Sorry for the waffle. Comments would be welcomed about if the system looks OK. Clearly obvious detail missing like stop values, draincocks, flow etc but it was taking ages to draw as is !!

Thanks.

 

[ChrisR]

Shower pump would need a flange off the HW cylinder.

 

[Blaze]

Shower pump would need a flange off the HW cylinder.

Thanks for info ChrisR.

Would this be something like a Surrey or York depending upon connection at cylinder ? with 22mm feeds. If so, is it also worth adding some full bore values for servicing ?

 

[ricarbo]

You might consider a new hot water cylinder as you can get better insulated one than those made in the '60's and if you order one with a scecond outlet for a shower, the additional cost isn't great and you'd get it in a few days, probably. You can choose where the second pipe is to go. You can choose a quick recovery type which has more coils inside. You can choose the size/shape. Then you don't need to muck about trying to adapt the present one. You're looking at about £150, I should think, plus fitting.
if you think the boiler isn't up to it, perhaps you should check it's rated output against your proposed demand. You'd get a good idea by completing the questionnaire on the 'Sedbuk' site. Or you could measure (with clip on pipe thermometers) the difference between flow and return boiler pipes on a cold day. If the difference on maximum demand , when all rooms up to required temperature is no more than about 10 degrees centigrade, then your boiler is powerful enough. You could perhaps reduce the demand on it by improving insulation.
Weather compensation incorporated in some programmable stats as they learn the room temp rate of rise and adjust start time accordingly. Saves wiring in extra outside sensor, with all it's upheaval to decorations and plaster.