gravity to fully pumped....

[peteisfishing]

Hi all, converting a gravity HW/pumped CH to fully pumped. All pipe less for those at the top of the old boiler are inaccessible, buried behind Kitchen units and under fitted wardrobes. This is what has been done so far:
Utilised the 28mm flow to cylinder for Flow to Air seperator-pump-bypass - 3 port.
Capped the old cylinder return
New CH flow from 3 port to old ch flow on top of old boiler
New cylinder return connected to old CH return then return to bloiler
Bypass into return.
New boiler fitted
returning in the morning to finish and commission

Have i missed anything obvious?

I asked the cust if any rads heat when only HW on, but this just led to a unclear answer and a argument between them both!!!!!!.......what issues would arrise if this was the case? I guess just one rad wouldnt work and would require re-piping.................
Cheers all

 

[cdodds2004]

i doubt any rads would be on the gravity mate!

 

[dancinplumba]

have had bathroom rad on gravity circs

 

[cdodds2004]

well if it is the case it would need re-piping, but i havnt seen it before. but as dancin says he has seen it! allsorts out there, you never no!

 

[mountainman]

have had bathroom rad on gravity circs

Quite a common configuration some years ago.

 

[zzzjim]

My old system BBU grav HWC ,pumped CH self circulates upstairs on HW when it feels like it . HWC fully hot . offending rad in room with HWC .

Takes an age to get many of upstairs rads involved . A symptom of plenty of Hot water ready !

Possibly a cause of vague / varied answers !

 

[diamondgas]

One thought peteisfishing, Is the hot water return tee'd in before or after the heating common return? Possibility of reverse circulation if before.

 

[peteisfishing]

it will be the last tee before connecting to the boiler....thanks for the replies folks

 

[diamondgas]

it will be the last tee before connecting to the boiler....thanks for the replies folks

Nice one! ... Use to be a thing of the past but I think there may be a resurgence on "fully pumped" systems as folk realise the limitations of the Combi!

 

[peteisfishing]

Job done, as feared, bathroom rad on old HW pipes, will need re-piping, did warn cust but no doubt they will moan about extra cost. but remainder working a treat

 

[dancinplumba]

nice one pete, bit of extra work for you, no fishing today then