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https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl DIY Forum >> Plumbing Questions >> external pump https://www.askthetrades.co.uk/cgi-bin/yabb/YaBB.pl?num=1424988791 Message started by h on Feb 26^th, 2015, 10:13pm

Title: external pump
Post by h on Feb 26^th, 2015, 10:13pm

Hi, conventional boiler at moment, changing to system boiler, can i keep the external pump? Thanks

Title: Re: external pump
Post by thescruff on Feb 27^th, 2015, 12:10am

Hi,

Bit more info would good on your intentions etc.

A system boiler has a built in pump so you'd need a low loss header or something similar.

What not go for a heat only boiler.

Title: Re: external pump
Post by h on Feb 27^th, 2015, 9:31am

Thanks for reply, i currently have a heat only boiler in a vented system with external pump close to water cylinder, im upgrading to a higher capacity boiler( worcester 30kw) because radiators arnt warming up quicker( 15 rads), i thought if i put a system boiler in which has a pump and also leave the external pump in then maybe itll pump through to the rads quicker? Can that work? Would i need to rewire the pump to make it work in tandem with boiler pump? Or would it work in tandem anyway? Thanks for the help

Title: Re: external pump
Post by thescruff on Feb 27^th, 2015, 5:17pm

If the boiler is large enough upgrading to a bigger one wont help.

The best way would be to modify the system and or increase the pipe sizes, assuming the existing pump isn't undersize.

A low loss header then feed the heating and hot water from that would be the best plan and perhaps the easiest.

Title: Re: external pump
Post by h on Feb 27^th, 2015, 6:17pm

Thanks for reply, the boiler at moment is a baxi solo 40/4 rs(12 kw)
On a general note would it be a problem if i left the extermal pump when installing system boiler, or is it better to take it off?

Title: Re: external pump
Post by thescruff on Feb 27^th, 2015, 11:04pm

Lots of potential issues, The pump in a system boiler is likely to be on the return, whereas the existing pump is likely on the flow, this can upset the balance unless you intend to have a sealed system and do away with the header tank.

Normally a pump inline will be ok but I wouldn't advice it without seeing the system and any implications.

Sounds like the system has been extended a few times and with that in mind I'd sooner upgrade the pipework

Title: Re: external pump
Post by h on Feb 28^th, 2015, 7:55am

Thanks for reply, its a sealed system, mains pressure, how can i send u images of my system?

Title: Re: external pump
Post by thescruff on Feb 28^th, 2015, 8:53am

wrote on Feb 28^th, 2015, 7:55am:

Thanks for reply, its a sealed system, mains pressure, how can i send u images of my system?

There's a how to post pics in the index, failing that I'll send you an email address.

Title: Re: external pump
Post by h on Feb 28^th, 2015, 9:25am

Sorry, failing to send images due to php resizing? Email would b better Thanks

Title: Re: external pump
Post by h on Feb 28^th, 2015, 9:42am

Hi, managed to upload images on my gallery, hope that helps thanks

[album]hussain&1425116340[/album]