I recently moved to a house with an oil fired Aga. After it sooted up, I adjusted the settings on the BM-30 type oil control valve but am struggling to get it settled again. The Aga is overheating even when the low fire is set at the lowest setting.
I couldn't find a clear set of instructions online so wrote my own in the hope it will help others. Grateful to anyone who can review my guide and let me know where I'm going wrong.
Any ideas anyone?
Control
High fire vs low fire
Troubleshooting
Principles
I couldn't find a clear set of instructions online so wrote my own in the hope it will help others. Grateful to anyone who can review my guide and let me know where I'm going wrong.
Any ideas anyone?
Control
- For both high fire (H) and low fire (L): turning anticlockwise increases the flow rate.
- The screw is very sensitive and each adjustment should be only a quarter turn.
- Wait up to 15m between each adjustment to allow flames to settle
High fire vs low fire
- The high fire setting controls the flow rate when the temp is lower than the thermostat setting.
- The low fire setting controls the flow rate when above thermostat setting (overheating).
Troubleshooting
- If orange flame: turn high fire [anticlockwise] .
- If overheating: check thermostat then turn low pass clockwise.
- If underheating: check thermostat then turn high fire anticlockwise.
Principles
- HF is the default operating mode.
- LF is only activated when the Aga is overheating and is activated automatically by the thermostat triggering the lever to drop.
- The HF should be set to achieve a steady blue flame with no sputter.
- The LF can be set with minimal flame, so that the flow is just enough to keep the Aga alight.
- As LF controls the flow only when overheating, LF should only be adjusted when the thermostat is on the lowest setting.
- The centre pin reflects the height of the slit valve - the higher the pin, the more fuel flows
- This is because the slit valve is sprung open (up) by default which is its highest flow rate setting
- The HF represents how high the slit valve can go.
- The LF represents how low the slit valve can go.
- So max setting is high fire fully anticlockwise
- This will produce an orange flame, so keep turning clockwise until a steady blue flame occurs
- If the Aga overheats (according to the thermostat setting) the lever will drop, pushing the pin down to trigger LF and reduce the opening of the slit valve (the low fire setting determines how closed it goes)
- The Aga is either at the low or the high fire rate, there is no in-between.