Upgrade to Indirect DHW using existing boiler

[NYAVGUY]

I would like to replace a 14 year old Rheem gas water heater with a new indirect DHW using my existing Burnham Series 2 boiler (80.2% efficient according to the sticker). I have had 4 professionals look at the system. 2 would just add a third circulator to the exisiting header and new pipe as needed and two want to totally re-pipe the boiler. The reasons they state were the same.
1. The existing header is only 1" and I need a 1 1/4" to support the two heat zones plus DHW.
2. The current circulators are connected to the boiler return and pulling the water, when it is better and more efficient to push the water
3. Except for the boiler, all other devices around it (air scoop, check valves, circulators, etc.) appear to be 20+ years old and I should replace it all now to avoid piecemeal repairs over the next 10 years

I already upgraded the boiler control to a Honeywell Aquatrol AQ25142B with outdoor reset and DHW priority.

Based on the information above, is it worth twice the cost to replace everything around the boiler now?

I also couldn't find much about which Indirect DWH are best. I like the Vaughn/Burhnam stone lined, but one plumber told me they are not good for the type of water we have on Long Island and reccomended Techtanium or Superstor.

Thanks

[neophytes serendipity]

I would consider having the piping redone.

When it is redone, have it configured to work with a future condensing boiler replacement.

Make sure valves are added for servicing.

[snupytcb]

I would like to replace a 14 year old Rheem gas water heater with a new indirect DHW using my existing Burnham Series 2 boiler (80.2% efficient according to the sticker). I have had 4 professionals look at the system. 2 would just add a third circulator to the exisiting header and new pipe as needed and two want to totally re-pipe the boiler. The reasons they state were the same.
1. The existing header is only 1" and I need a 1 1/4" to support the two heat zones plus DHW.
2. The current circulators are connected to the boiler return and pulling the water, when it is better and more efficient to push the water
3. Except for the boiler, all other devices around it (air scoop, check valves, circulators, etc.) appear to be 20+ years old and I should replace it all now to avoid piecemeal repairs over the next 10 years

I already upgraded the boiler control to a Honeywell Aquatrol AQ25142B with outdoor reset and DHW priority.

Based on the information above, is it worth twice the cost to replace everything around the boiler now?

I also couldn't find much about which Indirect DWH are best. I like the Vaughn/Burhnam stone lined, but one plumber told me they are not good for the type of water we have on Long Island and reccomended Techtanium or Superstor.

Thanks

[NYAVGUY]

I will post pictures tonight

[REP]

You can do whatever you like at this point as the boiler will be down and everything is easy to get to.
When I install a new boiler,I use a spirovent instead of an air scoop and I put in flange valves at each circulator so that if i have to change a circulator,I don't have to drain the system. I also put ball valves at the beginning and end of each loop for quick purge filling.
You could do some of this or none of this but depending on how old system is ,you should probably change the air vent and the bladder tank.
As far as tanks go,they all are a good choice just check the warranty.

[snupytcb]

i have never heard of techtanium, but the superstore is lifetime warranty.

[skippedover]

Pix would help but there are numerous ways to pipe the indirect. Perfection is probably not necessary as long as the rest of the system operates satisfactorily. For example, it might be easier to pipe the indirect independently of the rest of the system on a dedicated loop with its own Spirovent. Or it might be possbile to minimize the re-piping by just coming off the top of the boiler 1-1/4, thence to a bull headed tee and again, use a dedicated Spirovent to the indirect, leaving the original system the way it is. The other thought is that if the indirect is going to have a priority zone, the other zones won't even be used when the indirect is use. So in that case, the net water flow change is zero, since the other circs will be held off when the indirect zone is calling and once it's satisfied, the other circs will have as much water flow as they've ever had. With multiple circs, I'd be using a Taco zone relay like the SR-501 with DHW priority. As I said, that leaves the DHW issue as not impacting the old system at all as far as any additional flow is concerned.