Unvented cylinder with nested coils

[Ryler]

Vented are available where one coil is used for solid fuel and the other a standard boiler.
But do they exist for unvented off the shelf?

 

[picasso]

Try looking for solar unvented although it they can’t be used with solid fuel if used as an unvented cylinder.

 

[Ryler]

I'm thinking of connecting solid fuel.
It will solve a few issues for me. Like low pressure at taps and I can change from two vented cylinders to a single UV cylinder.

 

[picasso]

you cannot directly connect solid fuel to an unvented cylinder as there is no way of controlling the heat input.

 

[Ryler]

I currently use a Danfoss RAV1 to control the vented cylinder temp.
Which works extremely well.
I'd just fit that to the UV cylinder.

 

[ianmcd]

I currently use a Danfoss RAV1 to control the vented cylinder temp.
Which works extremely well.
I'd just fit that to the UV cylinder.

well dont expect your house insurance to pay out when it takes the roof off

 

[Ryler]

well dont expect your house insurance to pay out when it takes the roof off

Won't the T&P on the UV open in an over heat situation?

 

[ianmcd]

installing an UV requires a qualification called G3 and a Ravi stat does not conform, dont shoot the messenger, just telling you it wont, whether I agree is a different thing

 

[Ryler]

and a Ravi stat does not conform

It shuts down the flow when the set temp is reached. Same as the supplied zone valve.
Except its probably more reliable as no electrics involved.
Whats not to conform?

 

[ianmcd]

It shuts down the flow when the set temp is reached. Same as the supplied zone valve.
Except its probably more reliable as no electrics involved.
Whats not to conform?

ask the people that make the regulations, just telling you it will not conform , didnt say I agreed, but will say messing around with unvented and solid fuel is a really big no no unless you really know what you are doing

 

[bernardgreen]

Won't the T&P on the UV open in an over heat situation?

Very likely the Temperature and Pressure (T&P) relief valve will open and discharge hot water. With the pressure reduced cold water will be able to come into the cylinder and the T&P will close. As long as the solid fuel source of heat is providing heat to the cylinder the T&P will continue to open and close with slugs of hot water, and possibly steam, being discharged.

Solid fuel heat sources cannot be quickly switched off like a gas or electric boiler can be.

 

[ianmcd]

Very likely the Temperature and Pressure (T&P) relief valve will open and discharge hot water. With the pressure reduced cold water will be able to come into the cylinder and the T&P will close. As long as the solid fuel source of heat is providing heat to the cylinder the T&P will continue to open and close with slugs of hot water, and possibly steam, being discharged.

Solid fuel heat sources cannot be quickly switched off like a gas or electric boiler can be.

And if the T&P fails on an unvented with a solid fuel supply guess what happens ?

 

[Ryler]

And if the T&P fails on an unvented with a solid fuel supply guess what happens ?

Pressure builds and the expansion relief valve on the combination valve opens.

 

[ianmcd]

Pressure builds and the expansion relief valve on the combination valve opens.

T&P is temperature and pressure relief valve , just go ahead and do it and make sure you are just staying there yourself

 

[Ryler]

If you plugged the t&p port it should still discharge safely I would have thought?