Correct way to plumb a boiler stove with a non condensing oil boiler?

USER X

Hello,
I had a 30Kw boiler stove installed and had plumbers in to connect it into the heating system but they messed around for months and didn't finish the job. I've had a few plumbers look at it and i'm getting different approaches on how they plan to connect it into the system so just looking for advice on this.

The existing boiler is a 45Kw non-condensing oil boiler and it has an expansion vessel. The stove is a 30Kw boiler stove which has a Flow, Return, Feed and Overflow. The stove also has a mechanical safety valve to flush cold mains water through a separate coil if its over heating.

One plumber has suggested that both heat sources can be connected to the flow and return pipes without issue because if the pump on the return of the boiler is not running then water wont go to it so the stove wont heat the boiler and vice-versa. The stove needs to be open-vented with an expansion tank but i'm curious if the expansion vessel on the oil boiler should be removed? Are non-return valves necessary?

Also the boiler and stove appear to have pumps on their returns while the 3 zones have pumps on their flows - Is this normal/correct?

Dtp1979

USER X wrote: »

Hello,
I had a 30Kw boiler stove installed and had plumbers in to connect it into the heating system but they messed around for months and didn't finish the job. I've had a few plumbers look at it and i'm getting different approaches on how they plan to connect it into the system so just looking for advice on this.

The existing boiler is a 45Kw non-condensing oil boiler and it has an expansion vessel. The stove is a 30Kw boiler stove which has a Flow, Return, Feed and Overflow. The stove also has a mechanical safety valve to flush cold mains water through a separate coil if its over heating.

One plumber has suggested that both heat sources can be connected to the flow and return pipes without issue because if the pump on the return of the boiler is not running then water wont go to it so the stove wont heat the boiler and vice-versa. The stove needs to be open-vented with an expansion tank but i'm curious if the expansion vessel on the oil boiler should be removed? Are non-return valves necessary?

Also the boiler and stove appear to have pumps on their returns while the 3 zones have pumps on their flows - Is this normal/correct?

To be honest it's impossible to tell what's going on from your post.
Break it down a bit.
Has the stove been piped yet?
Is your hot water cylinder higher than the stove?
Have you a small tank in your attic?
It must be a gigantic heating system for a 45kw boiler!!

Dtp1979

USER X wrote: »

Hello,
I had a 30Kw boiler stove installed and had plumbers in to connect it into the heating system but they messed around for months and didn't finish the job. I've had a few plumbers look at it and i'm getting different approaches on how they plan to connect it into the system so just looking for advice on this.

The existing boiler is a 45Kw non-condensing oil boiler and it has an expansion vessel. The stove is a 30Kw boiler stove which has a Flow, Return, Feed and Overflow. The stove also has a mechanical safety valve to flush cold mains water through a separate coil if its over heating.

One plumber has suggested that both heat sources can be connected to the flow and return pipes without issue because if the pump on the return of the boiler is not running then water wont go to it so the stove wont heat the boiler and vice-versa. The stove needs to be open-vented with an expansion tank but i'm curious if the expansion vessel on the oil boiler should be removed? Are non-return valves necessary?

Also the boiler and stove appear to have pumps on their returns while the 3 zones have pumps on their flows - Is this normal/correct?

To be honest it's impossible to tell what's going on from your post.
Break it down a bit.
Has the stove been piped yet?
Is your hot water cylinder higher than the stove?
Have you a small tank in your attic?
It must be a gigantic heating system for a 45kw boiler!!

K.Flyer

There are too many people out there hooking stoves into heating systems, with no full understanding of how the existing heating system functions, so just be very careful.
I am in the middle of sorting out an utter disaster of a heating system where someone changed it from a perfectly working oil heating sealed system to an open vented system to accommodate a stove.
They did not do it right and the powerful circulation pump on the oil system caused constant pitching into the new expansion tank, which in turn saturated the attic in damp condensation causing a lot of damage.

USER X

Dtp1979 wrote: »

To be honest it's impossible to tell what's going on from your post.
Break it down a bit.
Has the stove been piped yet?
Is your hot water cylinder higher than the stove?
Have you a small tank in your attic?
It must be a gigantic heating system for a 45kw boiler!!

The stove has been piped, the stove fitter needed the pipes in to build the fireplace (Its an insert stove). So its piped to above the ceiling into the attic space.

The plumbers put in two twin coil 36x18 HW cylinders. I'm not convinced that we need the second coil because the stove's controller can open a valve to heat the water, then it closes the valve and starts heating the radiators. I think they were planning to have a coil always open for the stove but my concern would be that theres no control over the temperature of the water then and the water could get to scalding temperatures.

They left a make-up/expansion tank to be installed.

Theres about 30 rads on the system to heat a house of 480 sqm.

Dtp1979

USER X wrote: »

The stove has been piped, the stove fitter needed the pipes in to build the fireplace (Its an insert stove). So its piped to above the ceiling into the attic space.

The plumbers put in two twin coil 36x18 HW cylinders. I'm not convinced that we need the second coil because the stove's controller can open a valve to heat the water, then it closes the valve and starts heating the radiators. I think they were planning to have a coil always open for the stove but my concern would be that theres no control over the temperature of the water then and the water could get to scalding temperatures.

They left a make-up/expansion tank to be installed.

Theres about 30 rads on the system to heat a house of 480 sqm.

Is there 2 cylinders or 2 coils?
I think the type of stove you have can be joined to a sealed system, which I strongly disagree with. I'm really not a fan of mains cooling circuits.
When you say the stoves controller, what do you mean?
Snd ad always, a picture tells a thousand words!

USER X

K.Flyer wrote: »

There are too many people out there hooking stoves into heating systems, with no full understanding of how the existing heating system functions, so just be very careful.
I am in the middle of sorting out an utter disaster of a heating system where someone changed it from a perfectly working oil heating sealed system to an open vented system to accommodate a stove.
They did not do it right and the powerful circulation pump on the oil system caused constant pitching into the new expansion tank, which in turn saturated the attic in damp condensation causing a lot of damage.

Yeah, I could have put together a 4 zone heating system myself (3 x Rad circuits + DHW) but decided to call in the professionals because of the added complexity of integrating the boiler stove - i've read some horror stories of what can go wrong. Unfortunately the guys I hired got too busy with other jobs to finish this one so i'm without HW for 3 months, no zone control and a stove that I cant light because its not plumbed in :mad:

I am in the middle of sorting out an utter disaster of a heating system where someone changed it from a perfectly working oil heating sealed system to an open vented system to accommodate a stove.

Sounds just like what they were planning to do - changing it to an open vented system. Any pointers for doing it right?

Dtp1979

USER X wrote: »

Yeah, I could have put together a 4 zone heating system myself (3 x Rad circuits + DHW) but decided to call in the professionals because of the added complexity of integrating the boiler stove - i've read some horror stories of what can go wrong. Unfortunately the guys I hired got too busy with other jobs to finish this one so i'm without HW for 3 months, no zone control and a stove that I cant light because its not plumbed in :mad:


Sounds just like what they were planning to do - changing it to an open vented system. Any pointers for doing it right?

The only way to do it right and safe is to have it open vented. In K.flyers instance, the guys did have it open vented, they just didn't know how to do it right

USER X

Dtp1979 wrote: »

Is there 2 cylinders or 2 coils?
I think the type of stove you have can be joined to a sealed system, which I strongly disagree with. I'm really not a fan of mains cooling circuits.
When you say the stoves controller, what do you mean?
Snd ad always, a picture tells a thousand words!

There is 2 cylinders with two coils in each (2 x dual coil cylinders)

The stove has a controller which controls the motorised air choke, monitors the temperature of the stove, the upper and lower temperature of the HW Cylinders and controls the pumps/valves. So when the stove hits a set temperature of 45C, the controller will prioritise heating the HW. It opens the valve for the HW and heats the water to 65C. Once thats finished it will close the valve and start running the radiator zone pumps to heat the house. If the fire is burning too hot, it automatically chokes the air supply to calm it down.

roy rodgers

USER X wrote: »

The stove has been piped, the stove fitter needed the pipes in to build the fireplace (Its an insert stove). So its piped to above the ceiling into the attic space.

The plumbers put in two twin coil 36x18 HW cylinders. I'm not convinced that we need the second coil because the stove's controller can open a valve to heat the water, then it closes the valve and starts heating the radiators. I think they were planning to have a coil always open for the stove but my concern would be that theres no control over the temperature of the water then and the water could get to scalding temperatures.

They left a make-up/expansion tank to be installed.

Theres about 30 rads on the system to heat a house of 480 sqm.

480sqm massive house.
I'd personally would of put a buffer tank to take that sort of heat away. Your never gonna heat the whole house with the stove and probably would feel it's not working at its best.
I'd put a buffer tank in and zoning and disturb the heat to other parts of the house when needed.

Dtp1979

USER X wrote: »

There is 2 cylinders with two coils in each (2 x dual coil cylinders)

The stove has a controller which controls the motorised air choke, monitors the temperature of the stove, the upper and lower temperature of the HW Cylinders and controls the pumps/valves. So when the stove hits a set temperature of 45C, the controller will prioritise heating the HW. It opens the valve for the HW and heats the water to 65C. Once thats finished it will close the valve and start running the radiator zone pumps to heat the house. If the fire is burning too hot, it automatically chokes the air supply to calm it down.

Ye they're the type of stoves I hate to be honest. Maybe connected to an open vented system they're ok but I don't think you can with those. What happens when there's a power failure or the damper remains stuck open?

gctest50

you get them oval-shaped to slip through doors a bit easier if its an afterthough

this sorta craic :

http://www.dunsterwoodboilers.co.uk/akvaterm.php


https://issuu.com/akvaterm/docs/2015_katalogi_v8_eng

gctest50

Dtp1979 wrote: »

Ye they're the type of stoves I hate to be honest. Maybe connected to an open vented system they're ok but I don't think you can with those. What happens when there's a power failure or the damper remains stuck open?

they'll be scraping what's left of you off the wall for weeks