swop out Worcester 350RSF combi with Greenstar 37CDI combi

[t22]

Hi All

My 19 year old WB 350RSF wall mounted combi needs a new Expansion Vessel so rather than get this changed I am considering getting the boiler replaced with a modern condensing combi hoping that in the long run it will be more economical (ie less gas consumption)

consideing the Worcester Bosch Greenstar 37CDI but the pipe layout is in a different sequence & the position of the side flue is also different

boiler is mounted in the corner of an integral garage with pipe work dropping down through the rear of the 350. (the pipework cannot be changed above the ceiling)
unfortunately there would not appear to be much room to swop over the pipe order to match the 37CDI at the rear

But if the boiler was fitted 75mm off the wall in the same position (maybe slightly lower) this would allow for the same flue hole to be used and for enough room behind to change over the order of the pipework

would the fitting of two vertical lengths of 75x75mm timber suffice or should the framework be non combustible ?

what are the experts thoughts on swopping out for a 37CDI ?

 

[landyandy]

Have you considered fitting an external expansion vessel

Andy.

 

[t22]

Hi Andy

thanks for your suggestion much appreiciated & sound advice - though while replacement internal EV's are still available for the 350RSF at approx £65 I would prefer an internal one

but what are the thoughts of totally replacing this boiler with a combi or is it just a waste of money & would I be better off just getting the EV replaced ?

 

[twgas]

What is actually wrong with your ex vess?

 

[nickso]

EV for a 350 is very easy to change. i would keep it myself although i believe there are some obsolete parts for it now.

 

[t22]

Hi Nickso & Twgas

the EV has sprung a leak internally & the air escaped & has collected in the nearest upstairs Rad to the boiler.

& yes this EV looks very easy to change just 1 bolt & 1 clip - would just have to ensure it had been drained of water first before removing


If I vent this air out & repressurise the system with water when the heating is on the pressure rises close to 3bar , so as a temp measure Ive just admitted air into one of the rads to allow the system to work until I either get the EV replaced or take the opportunity to go for a condensing boiler assuming the long term running costs will be cheaper


cheers