Boiler upgrade options

[u0362565]

Hi all,

We're looking to update our existing central heating setup and wanted to get a few more opinions. We currently have an open vented conventional boiler with cold water expansion tank in attic and indirect vented hot water cylinder. Initially we thought we would just swap to a combi boiler to remove all tanks. However, the other option is to keep existing boiler and convert hot water cylinder to sealed/pressurised system. It's a 3 bed house, 2 bathrooms with 2 adults. Both showers are electric, no bath. If you have the space it sounds like option 2, sealed pressurised cylinder and existing boiler might be advantageous in that you have ample mains pressure hot water but is this a more complex setup than a combi? Any thoughts in general as to what the better setup is or does it just depend on water usage. Thanks for the help.

 

[ShaunCorbs]

Are you planning on changing the showers from electric to mains hot in the future?

 

[u0362565]

Are you planning on changing the showers from electric to mains hot in the future?

Hi Shaun, yes at least one shower on mains hot water. maybe keep one electric for redundancy if there is an issue with the boiler.

 

[ShaunCorbs]

You could go combi as your only having one shower possibility using hot water

 

[u0362565]

You could go combi as your only having one shower possibility using hot water

We had a suggestion that converting to a pressurised hot water cylinder may pave the way to a conversion to heat pump in the future but I suspect at least a new cylinder would be required at that time but at least all the plumbing would be in place. Sorry forgot to mention that in the post. If that is removed for combi it may need reinstating in future

 

[ShaunCorbs]

New cylinder and new rads also possible new pipework so basically new heating system if you want it hp ready

 

[gmartine]

Unless there's a plan for more HW users (kids?) a combi would suffice unless you're already clashing in the bathroom because say you both take long showers. What's the main motivator for changing the system?

 

[u0362565]

The central heating seems to work fine, not gone through a winter with it yet but rads get hot and reasonable even temp top/bottom on most, pipes are microbore. Hot water from the vented cylinder is main issue or lack of it, doesn't get hot enough. Also have large cold water tank in attic feeding cylinder and want rid of it, this is in addition to vented expansion tank in attic.

Agree Shaun, switch to heat pump eventually means new larger pipes and rads, but if we already did the sealed cylinder we'd be a little way there. If we remove the cylinder in the case of combi this almost has to be undone again and cylinder plumbing put back in if eventually heat pumps become the norm. Perhaps it's not worth considering the future too much and just deal with here and now.. We're used to a combi boiler as we had in previous property so were just going to swap to that but then had the sealed cylinder option on existing boiler as anorher option

 

[gmartine]

You can wire up a combi for use with an unvented cylinder. Use the combi to provide instantaneous HW for say kitchen and other smaller outlets and use cylinder HW for bathrooms and get rid of electric showers completely as you can have immersion for backup and so contributing a bit to your future proofing plan.

Quite an efficient system actually as combi will have an excess of power to charge cylinder and usually better modulation than regular or system boiler.

 

[u0362565]

You can wire up a combi for use with an unvented cylinder. Use the combi to provide instantaneous HW for say kitchen and other smaller outlets and use cylinder HW for bathrooms and get rid of electric showers completely as you can have immersion for backup and so contributing a bit to your future proofing plan.

Quite an efficient system actually as combi will have an excess of power to charge cylinder and usually better modulation than regular or system boiler.

Ok thanks, so sounds like best of both worlds in terms of operation but perhaps more complex and costly as would need new combi boiler and sealed cylinder. Although I don't like electric showers, wonder if having one electric isn't bad idea though in case boiler goes down.

 

[Deleted member 120897]

Ok thanks, so sounds like best of both worlds in terms of operation but perhaps more complex and costly as would need new combi boiler and sealed cylinder. Although I don't like electric showers, wonder if having one electric isn't bad idea though in case boiler goes down.

They’re a good idea as a backup. I work in social housing and the vast majority of our properties have an electric shower, I think this may have been the reasoning behind it.

Hot water from the vented cylinder is main issue or lack of it, doesn't get hot enough. Also have large cold water tank in attic feeding cylinder and want rid of it, this is in addition to vented expansion tank in attic.

What’s the cylinder thermostat set to? Has it been checked it’s working correctly? Is it connected to the cylinder correctly? Ha so the motorised valve(s) been checked?

 

[u0362565]

They’re a good idea as a backup. I work in social housing and the vast majority of our properties have an electric shower, I think this may have been the reasoning behind it.

What’s the cylinder thermostat set to? Has it been checked it’s working correctly? Is it connected to the cylinder correctly? Ha so the motorised valve(s) been checked?

It doesn't have a thermostat and the cylinder heats if the heating is on there is no separation so it's a bit of a mess. And apparently it has 10mm input pipe and been told it's just not been done correctly so it either goes completely in case of combi or swap for new sealed. Another caveat is that we're having a rewire soon so floors will be up making possibility to change all pipes which paves the way for heat pump in future but generally at least 15mm is probably better than 8mm! Which is what we have now