The Summerlands Chuffer is well established and proven to give the best possible Chuff on Roundhouse locos. On some locos, though, the chimney space is marginal and the additional diameter of the Chuffer with FX Control fitted might compromise the burner stability. On most locos this is easily overcome by the addition of an air control ring on the burner, but for those who would prefer the Chuffer control to keep to the original diameter, we offer an exchange service where the 7/32" diameter Chuffer is used.
The FX Control sits 2mm highter in the chimney, so on some locos, such as Russel and Talieasin, an exchange Chuffer is essential. On locos which use the 3/16" Chuffer, an FX Control is not possible.
So in the list below, you will see that you have a choice of two options on a number of locos.
Option A will be a simple fitting of the FX Control - but may require a simple air control ring for the burner.
Option B will exchange your Chuffer for the smaller one to maintain the diameter
A or B?
If in doubt, you can do a simple check with your loco. Place a short length of 9/32" OD K&S tube over the Chuffer in your loco and check the lighting and burner stability. This tube is slightly larger than the FX Control, but will give you an indication of the effect on breathing.
What is an air control ring?
This is a simple strip of metal (like a tiny boiler band) that wraps round the rear burner tube and is held with a screw and bolt. It can be slid forward to reduce the air flow. Adjustment is by trial and error and beware that too little air will result in incomplete combustion. You can smell this!
Lilla - SCGP4. It may be possible to fit FX but at this stage (Oct 17) I do not know.
Garratt - There are two versions for the Roundhouse Garratt and they are made to order only. Please note that fitting either of them has warranty implications - if in doubt, please speak to your supplier or Roundhouse.
The SCRH7-RH is the same outside diameter as the Roundhouse simple exhaust and has the sme characteristics for lighting - at the top of the chimney as normal.
The SCRH7- FX has the 7/32" chuffer with FX Control. As it is larger than the RH exhaust it makes lighting at the base of the smokebox easier.
Lilla - see below