Circuit diagram wood burning stoves with boilers


Now that we have looked at the primary circuit, the heat sink radiator and pumped radiators we can look at the complete system in one circuit diagram. Firstly let’s look at a two port boiler stove:

circuit diagram wood burning stoves with boilers

IMPORTANT NOTE: The pipework between the top of the coil and where it meets the vertical pipe (bit of pipe B is attached to) should have a slight rise from the cylinder to the vertical pipe (unlike the drawing where it has a slight fall which is wrong) to prevent air trapping in the area at the top of the coil.

 

Secondly let’s look at a four-port boiler stove (this is the easiest way of doing things in my opinion and no injector T required):

circuit diagram wood burners

Ignore the injector T reference as there is no such part in this circuit. IMPORTANT NOTE: The pipework between the top of the coil and where it meets the vertical pipe (bit of pipe B is attached to) should have a slight rise from the cylinder to the vertical pipe (unlike the drawing where it has a slight fall which is wrong) to prevent air trapping in the area at the top of the coil.

I have added two extras in this diagram, EITHER of which is demanded by Building Control in Document G (3.13). Of course you can fit both if you wish. The first option (B) is a valve that will close the circuit to the cylinder in the case of the cylinder overheating (set high at say 90 degrees centigrade) – a normally closed two port valve will do. The other option (that I choose) (F) is a temperature relief valve close to the top of the cylinder that sends water safely off to outside should the cylinder overheat (the same as somebody using a hot tap) NOTE THAT THIS VALVE NEEDS TO BE FITTED SO AIR CANNOT TRAP UNDERNEATH IT AND STOP IT WORKING – I.E. VENT NATURALLY AWAY FROM THE VALVE (essentially slide it into a pipe that is pointing uphill slightly away from the valve).

More in BOILER STOVES> Key Building Regulations.

Note: The pipe leaving the top of your coil (usually 22mm) should rise slightly between cylinder and where it meets the primary circuit so air is not trapped at the top of your coil. If you are looking for this on my diagrams above it is the pipe that “B” is strapped to. I also add a T off of this pipe with a manual 15mm gate valve on the end. Then, if air were to trap in the coil during filling (can happen) I can add a hose and flush it through.

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