Vailant combi with cylinder

[b21playa]

To do it you would NEED the combi's "CH" side to come on,
as you need the CH pipework up to where you Tee it off with zone valves to be actively heated.


To put it into perspective, a normal system boiler only has "CH" flow and return, unlike a combi's HW in & out, CH Flow & Return.

You add the gubbings to control where the "CH" hot water goes with zone valves on seperate pipe runs to the radiators and cylinder,
the zone valves control where the water can go and external controls tell the boiler when to fire and which valves to operate.

have a look at S or Y plan as suggested, you need to put all the external controls in place (Room thermostat, cylinder stat, timer/programmer) then tell the combi on it's front panel you want CH constantly.
Once both thermostats are satisfied, the boiler will turn off for the CH side.
Add in the programmer so you can say when you want Cylinder HW and/or Heating, once the thermostats tick over, boiler stops heating.

if you turn the "CH" side of the combi off, you'd turn the heating and cylinder heating off.

Pump is built into the combi normally and should be able to handle it,
I'd suggest getting someone competent to design and do the above

Looking at the diagrams provide here http://wiki.diyfaq.org.uk/index.php?title=Central_Heating_Controls_and_Zoning, its making a bit more sense to me.

I called a few local plumbers today and they didnt seem interested.

Look at the diagrams the Y-plan looks like alot less valves to buy and fit.

Currently I have the ecotec 837 boiler which is controlled by a VRT 392f. Could this still be used, or would I need to replace this?

I understand I need to split the flow and return straight from the boiler before any rads. Add a 3port mid-position valve on the flow side and nothing on the return, jut to ensure its connected as close to the boiler.

When my bathroom and kitchen was done, they piped hot and cold in 15mm. As the units are in the way, I can not upgrade to 22mm. Would it be ok, to change to 22mm as close as possible to the main stop cock (about 1m) from 15mm to feed the tank, and then run 22mm for hot water to the furthest I can get for DHW?

The VRT won't be suitable. It is just a wireless thermostat for controlling
central heating. Although I haven't looked into it further. I would normally start with a 2 channel programmer like a Honeywell st9400.
3 port mid position valve will be fine but the wiring can confuse some.
Wrong time of year I suppose getting interest from plumbers especially with the weather just at the moment. Most plumbers will be completely confused combi boiler and hot tank "impossible". I've seen many plumbers quote and install system boilers replacing perfectly good boilers that would
have easily done the job.

I think it was the "combi" part that confused them totally.

Im no plumber but this doesnt seem all that complicated now, maybe the wiring, which i need need an electrician for anyway. Mid-position valve would need to be close to the floor under kitchen units due to pipe locations, would that be ok?

Im thinking of running all the pipework, site the tank and then get someone to commission it and install the vessel

would I be ok in increase pipe sizes for hot/cold?

 

[b21playa]

Are there any recommended cylinders

What about warmflow, can get a 210litre for £510 including expansion kit

 

[dcawkwell]

Are there any recommended cylinders

What about warmflow, can get a 210litre for £510 including expansion kit

I think you will struggle to find anyone.
They will either want to take on the whole job or nothing at all.
Cylinder size isn't all that critical as the reheat times for cylinders
are very quick. 210 sounds ok for the house size.
Most electricians seem to be confused by central heating circuits
as it isn't their usual area. House wiring yes. central heating no.

 

[b21playa]

Are there any recommended cylinders

What about warmflow, can get a 210litre for £510 including expansion kit

I think you will struggle to find anyone.
They will either want to take on the whole job or nothing at all.
Cylinder size isn't all that critical as the reheat times for cylinders
are very quick. 210 sounds ok for the house size.
Most electricians seem to be confused by central heating circuits
as it isn't their usual area. House wiring yes. central heating no.

is the warmflow good/ok? 22min reheat

My brother-in-law to be in part p qualified, I could get him to do it

 

[dcawkwell]

Are there any recommended cylinders

What about warmflow, can get a 210litre for £510 including expansion kit

I think you will struggle to find anyone.
They will either want to take on the whole job or nothing at all.
Cylinder size isn't all that critical as the reheat times for cylinders
are very quick. 210 sounds ok for the house size.
Most electricians seem to be confused by central heating circuits
as it isn't their usual area. House wiring yes. central heating no.

is the warmflow good/ok? 22min reheat

My brother-in-law to be in part p qualified, I could get him to do it

Quite a lot of the cylinders are made by a few companies and just re-badged. Nothing to choose between them really. Most come with a 10year warranty. Some more.

 

[b21playa]

http://www.heatandplumb.com/acatalo...nless_Steel_Hot_Water_Cylinder_210_LITRE.html

This is the one