Fitting combi or system boiler to existing system with an open vented cylinder

[Indigo Install]

Hi Guys

Looking for a bit of advice. Been asked to replace boilers on two separate systems, both are open vented heating systems with open vented hot water cylinder, one with a baxi backboiler the other with a vulcan floor standing atmospheric. In both situations a replacement boiler would need to go elsewhere.

Looking likely for the baxi replacement that the boiler will have to go in the loft - the position of tanks rules out staying as open vent. Given that the boiler would be in the loft it would mean that the hot water from a combi would have a long way to go to the kitchen, so a system boiler plumbed into the existing system (with appropriate alterations), including the cylinder, would mean that there is no change to the existing hot water 'experience'.
The vulcan replacement could still be heat only boiler in its new position, but I am looking at the possibility of either a system, utilizing the existing cylinder, or a combi also using the cylinder but also directly supplying the kitchen.

I've never done this before to an unvented cylinder, it doesn't seem to be an unreasonable thing to do and pretty much use the existing controls. My concern is regarding the integrity of the coil within cylinder (and indeed the system as a whole - the vulcan system is 30+ years old)

• is there any reason why this shouldn't be done
• what should I check for
• etc

Any thoughts and advice would be greatly appreciated

Jonathan

 

[SafeGasInstall]

welcome to forum , you will be better of with a system boilers , however old system likely to leak so new pipes will be better option but knowing the market you will probably have to do a pressure test and get customer to sign disclaimer

 

[Centralheatking]

It is quite a good trick to install a combi which supplies the hot direct to the adjacent kitchen
and then heats the cylinder for the rest of the property.

However combis are awash with problems - esp hooked into old systems which might not take the pressure of 1.5- 2.0 bar.

I would go down the system (conventional) route, it is more complicated and takes up more space but is so much better in larger homes. Otherwise you can go down the 1m Kw combi
boiler route - which means buying a way over rated boiler JUST to get the hor water supply
up to needs. and that depends on the mains water supply which is also variable.

Combis are for small houses and flats with limited space AND central heating fitters who are
not capable of designing and fitting a system set up. Its so easy to bang a do it all box on the wall.


centralheatking

 

[Ermintrude]

My sentiments exactly. Our sales man is still non stop on back boiler or open vent to combi though. If old system simply run in a 15mm DHW to outlets in leu of 22 or old lead. I would fit a combi to nothing bigger than a 3 bed 1.5 bath. With good water pressure.

 

[AWheating]

what do your customers want?

 

[Ermintrude]

what do your customers want?

What all customers want .... A quality boiler cheap. When your half price sale is on and your offering £400 scrappage, 10% oap discount and free servicing for 10 years.... And to do it tomorrow doh!

 

[AWheating]

im offering a 50% disscount on combi for combi swaps at the monent. WB cdi for £ 4000 instead of £8000. with a free internal filling loop.

 

[cr0ft]

Don't forget that to comply with Sales Regulations you have to state that the higher price was charged for X amount of days between Date X and Date Y 🙂

 

[Rob Sale]

for the baxi back boiler have you thought about baxis new condensing back boilers. they are cheap from plumb center, easily swapped.

 

[Ermintrude]

for the baxi back boiler have you thought about baxis new condensing back boilers. they are cheap from plumb center, easily swapped.

Bbu are carp. Old Bermuda top shelf... New ones with conny pump = pish. Plus old cylinder and controls probably not part l or in particularly good health??

 

[AWheating]

Don't forget that to comply with Sales Regulations you have to state that the higher price was charged for X amount of days between Date X and Date Y 🙂

like asda, tescos etc...... i hiked the price up for 2 days then called it a half price sale. 🙂

maybe i should do a dfs........