Rejuvenating an old-style Hot Water Heating system

Doug Lindsay

I am a retired, (sort of), PHC contractor/Building Maintenance Supervisor, now keeping busy helping friends with their outdated heating systems. The case in point is a Weil-Mclain hot water boiler, size 167/series 1 and rated at 390 square ft. of Steam and 625 square ft. of water.
It is equipped with a Beckett burner, and fired at .85 gals. Burner is rated at 1.40 gals., max.
The boiler maintains temp. at 160 degrees, high limit set at 200. The circulator cycles on a call for heat, to feed the cast-iron, free standing radiators in the living area of this approx. 1000 square ft. house. The boiler is shut down in the Summer.
Anyone can see that this arrangement is going to have a long heating lag time.
The house is Brick & cinder-block with wood-frame interior, and has plastered walls. Since it was built in 1950, I have to assume that there isn't much insulation.
The house is a Cape style, but is only heated on the first floor. There is a finished room on the second floor but it is heated by a propane Fire-place/stove unit. There is a total of 5 radiators, one each in the Living room, Kitchen, 2 Bedrooms, and the Bathroom.
The boiler, while old and inefficient in it's present configuration, is still in good condition. The piping arrangement is a split loop with flow tees.

The burner has been upgraded at some point, not to state of the art, but also not exactly a "Silent Glow." The combustion chamber almost doesn't exist and needs to be replaced and backfilled properly. Also the burner-tube entry needs to be built-up and sealed. The dimensions of the fire-box are 15"X27".

Can anyone tell me what size chamber this boiler should have, and if there is a pre-cast chamber available, or whether it would be necessary to fabricate one from a Fiber-Frax type, soft, formable material?

Question 2:
It seems to me that this system would provide a lot more comfort and many less peaks and valleys of temp. swing if it were set up with an outdoor reset.
Can anyone out there help me with a sketch of the needed control setup and/or other suggestions to enhance this system?
I have done a lot of burner service & heating/cooling installations, but not much burner or chamber replacement.
Any help from you "Blue-Collar Professionals" out there will be greatly appreciated, and you'll be helping me help a friend.
Doug Lindsay
dlindsay9067@sbcglobal.net