The 109 second stage was the "Adjustable" while the 156 "Balanced Adjustable" is a later version of the same reg with a balanced poppet. This same poppet and balance chamber was used in the G250 design. Consequently both the Balanced Adjustable and G250 offer essentially identical performance with the only difference being the adjustable flow vane on the G250 - that most people left more or less in the middle anyway where it gave the same venturi effect as the Balanced Adjustable had.
Any 109 adjustable can be upgraded to use the current "S-wing" balanced poppet used in the G250HP, S600, and S550 and when you do so it basically becomes the latest configuration Balanced Adjustable. It requires a G250/S600 annual service kit as well as a new balance chamber and a new spring. In the oldest (late 60's) 109's a new G250 lever may also be required as the shape of the tabs were changed on the alter regs. In any event, with the current 109 "Adjustable" poppet, you need the new lever anyway, so it's an annual service issue more than a converion issue for very old 109's.
The spring is about a $1.50, the lever is around $6.00 and the balance chamber is also around $1.50 (it used to come in G250/S600 service kits but is no longer included.) The annual service kit itself is around $10.00. So for around $20 in parts you can upgrade a 109 to G250 performance levels and there should be no additional labor charge if it is done in conjunction with an annual service.
I have see few 109's that were not salvageable, but if they are badly corroded it can be challenge. If the orifice is even slightly corroded, performance will suffer badly and it will need to be replaced to get decent performance. A new plastic orifice can be installed for about $6.00.
SP used to package an upgrade kit but stopped doing so several years ago when sales fell off after most 109's in active use by interested owners were converted to the current 156 status. They still sell all the parts, but most shops have to call SP to get the correct parts ordered as they do not do the conversion all that often anymore.
I ordered parts to do a number of upgrades a few years ago and still have 2 or 3 in stock. Unless the customer objects or has a specific preference, I tend to upgrade 109's to 156 standard when they come through for annual service. The lighter spring used in the 156 results in less engraving of the soft seat and fewer problems with freeflows from an excessive seating groove over the course of a 12-13 month annual service period. Plus G250 kits are common and always in stock just about anywhere on the planet which makes it easier for a customer to get an emergency fix if they are on a dive trip.
I don't mind doing the upgrade via mail as most "new" techs at the average SP dealer are not familiar with it. Labor rates run $10.00 per stage for an annual service and I prefer to have the first stage at the same time so the second stage can be properly tuned to it. Shipping seems to run $15-$18 each way depending on insurance and residential versus comercial delivery address. So a first and second stage annual service plus 156 upgrade would run around $80-$90 for parts, labor and shipping.
Any 109 adjustable can be upgraded to use the current "S-wing" balanced poppet used in the G250HP, S600, and S550 and when you do so it basically becomes the latest configuration Balanced Adjustable. It requires a G250/S600 annual service kit as well as a new balance chamber and a new spring. In the oldest (late 60's) 109's a new G250 lever may also be required as the shape of the tabs were changed on the alter regs. In any event, with the current 109 "Adjustable" poppet, you need the new lever anyway, so it's an annual service issue more than a converion issue for very old 109's.
The spring is about a $1.50, the lever is around $6.00 and the balance chamber is also around $1.50 (it used to come in G250/S600 service kits but is no longer included.) The annual service kit itself is around $10.00. So for around $20 in parts you can upgrade a 109 to G250 performance levels and there should be no additional labor charge if it is done in conjunction with an annual service.
I have see few 109's that were not salvageable, but if they are badly corroded it can be challenge. If the orifice is even slightly corroded, performance will suffer badly and it will need to be replaced to get decent performance. A new plastic orifice can be installed for about $6.00.
SP used to package an upgrade kit but stopped doing so several years ago when sales fell off after most 109's in active use by interested owners were converted to the current 156 status. They still sell all the parts, but most shops have to call SP to get the correct parts ordered as they do not do the conversion all that often anymore.
I ordered parts to do a number of upgrades a few years ago and still have 2 or 3 in stock. Unless the customer objects or has a specific preference, I tend to upgrade 109's to 156 standard when they come through for annual service. The lighter spring used in the 156 results in less engraving of the soft seat and fewer problems with freeflows from an excessive seating groove over the course of a 12-13 month annual service period. Plus G250 kits are common and always in stock just about anywhere on the planet which makes it easier for a customer to get an emergency fix if they are on a dive trip.
I don't mind doing the upgrade via mail as most "new" techs at the average SP dealer are not familiar with it. Labor rates run $10.00 per stage for an annual service and I prefer to have the first stage at the same time so the second stage can be properly tuned to it. Shipping seems to run $15-$18 each way depending on insurance and residential versus comercial delivery address. So a first and second stage annual service plus 156 upgrade would run around $80-$90 for parts, labor and shipping.
