Vailant combi with cylinder

[b21playa]

Hi all

Is it possible to add a unistore to a combi boiler?

I am thinking about converting our loft into a room with en-suite, and the current boiler (ecotec 837) would not be sufficient to run 2 showers and all the taps. Currently if the shower is on, and a tap is opened, there is noticable pressure drop, so an electric shower was fitted to our downstairs shower room.

I need it, so that both showers can be used at once and taps can be opened without a drop in pressure

Thanks in advance

 

[namsag]

Ca be done but do you have sufficient incoming mains pressure to supply it

 

[b21playa]

Ca be done but do you have sufficient incoming mains pressure to supply it

I have no idea on what bar or flow rate the incoming is. All I know it has been changed to mdpe pipe before I purchased the house

 

[b21playa]

sorry to bring up an old topic, but how can this be done and where does tge tank need to sit in relation to the boiler.

currently boiler is in the kitchen

 

[dcawkwell]

Yes it can be done. Using the heating pipes from the boiler to
heat the hot water tank just as in a conventional system boiler.
An unvented cylinder can be placed anywhere in the house.
Since you are converting the loft I suggest there. But if you have a garage
or old tank cupboard there is just as good.
If you have a flow of 25 litres a minute you should be ok
an installer will be able to advise.

 

[b21playa]

Yes it can be done. Using the heating pipes from the boiler to
heat the hot water tank just as in a conventional system boiler.
An unvented cylinder can be placed anywhere in the house.
Since you are converting the loft I suggest there. But if you have a garage
or old tank cupboard there is just as good.
If you have a flow of 25 litres a minute you should be ok
an installer will be able to advise.

Only been a year since I done my kitchen. Would the flow and return pipes from the boiler need to go to the cylinder first, or can it be T'd from anywhere on the circuit?

Do you have any further information I can use to read up? Was planning on fitting the tank myself and getting an electrician to wire up anything that needs to be done.

I don't know if the loft conversion is being done now, but still need to sort out water drop. Was thinking I could locate it in the corner of the garage and create a cupboard

Thanks in advance.

 

[dcawkwell]

Yes it can be done. Using the heating pipes from the boiler to
heat the hot water tank just as in a conventional system boiler.
An unvented cylinder can be placed anywhere in the house.
Since you are converting the loft I suggest there. But if you have a garage
or old tank cupboard there is just as good.
If you have a flow of 25 litres a minute you should be ok
an installer will be able to advise.

Only been a year since I done my kitchen. Would the flow and return pipes from the boiler need to go to the cylinder first, or can it be T'd from anywhere on the circuit?

Do you have any further information I can use to read up? Was planning on fitting the tank myself and getting an electrician to wire up anything that needs to be done.

I don't know if the loft conversion is being done now, but still need to sort out water drop. Was thinking I could locate it in the corner of the garage and create a cupboard

Thanks in advance.

You will not be able to install the tank yourself. With it being a pressurised vessel and therefore dangerous if not installed correctly it has to
be done by a qualified person.

Take a look at S plan or Y plan systems for piping configurations.

 

[b21playa]

Yes it can be done. Using the heating pipes from the boiler to
heat the hot water tank just as in a conventional system boiler.
An unvented cylinder can be placed anywhere in the house.
Since you are converting the loft I suggest there. But if you have a garage
or old tank cupboard there is just as good.
If you have a flow of 25 litres a minute you should be ok
an installer will be able to advise.

Only been a year since I done my kitchen. Would the flow and return pipes from the boiler need to go to the cylinder first, or can it be T'd from anywhere on the circuit?

Do you have any further information I can use to read up? Was planning on fitting the tank myself and getting an electrician to wire up anything that needs to be done.

I don't know if the loft conversion is being done now, but still need to sort out water drop. Was thinking I could locate it in the corner of the garage and create a cupboard

Thanks in advance.

You will not be able to install the tank yourself. With it being a pressurised vessel and therefore dangerous if not installed correctly it has to
be done by a qualified person.

Take a look at S plan or Y plan systems for piping configurations.

Oh right

Just looking at mrcentralheating.com 250l tank for £610. would this work with my vaillant?

Just so I know if this is viable for me or not, can it be connected to the heating pipes that go to my radiator, or does it need to be piped from boiler to cylinder?

 

[dcawkwell]

You will need to have a separate set of 22mm pipes from the boiler.
One set for central heating one set for hot water tank.
Otherwise the only way you could heat the tank would be when the central heating was on.

 

[Agile]

It needs to have its heating coil piped back to the boiler otherwise it cannot be controlled unless the heating is on.

Should be in 22 mm but would work with 15mm with a longer reheat time if that was not crucial.

As it would normally have an immersion element that could be used to get a faster reheat in unusual cases.

Of course if its only for limited use for guests or teenage boys then an immersion only reheat might suffice and save costs.

Tony

 

[b21playa]

You will need to have a separate set of 22mm pipes from the boiler.
One set for central heating one set for hot water tank.
Otherwise the only way you could heat the tank would be when the central heating was on.

I guess the seperate set would need to be tee'd off the pipes coming from the boiler, before any radiators?

Do i Also need a pump?

But then how would this stop the central heating coming on when the tank is heated?

 

[warmadmax]

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

 

[algas]

The flow to the cylinder should come off before any radiator & the return from cylinder the last connection to the boiler.

 

[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?

 

[dcawkwell]

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.