Replacing old line voltage zone controls and thermostats.

swvawethead

The title of the thread is if I am correct in my assumption after observing the wiring, etc.
We have two zone system in a 1950s era home that started out with oil but converted to gas Burnham sometime in the mid 1980s. I am guessing the old relays were retained during the conversion. Two fairly large things missing covers with heavy gauge wires and transformers. When the art-deco looking thermostats call for heat there is a very loud clacking noise at the relay/switch (?) in the boiler room that starts the chain of events such as firing the boiler and runs the circulators.

Couple years ago I attempted to replace the old time thermostat with something newer but encountered the heavy gauge wires coming out of the wall. Never bothered taking a voltage reading to check if it is 24V.
The house was overbuilt back in the days and was wired with 12 gauge for lights and outlets.

I would like to tidy up this setup with a zone control box and get rid of the old stuff and properly run wires to the boiler and circulators.

The Burnham (standing pilot) dumb boiler with steel expansion tank has run with zero problems and all I've done is occasionally remove and check the burner tubes, change out the thermocouple and monitor the system pressure.

But the installers ran the 3 wires from the ungrounded old boxes and did not connect the ground wire to the pumps.
Some other spots where ground wire not connected during the boiler swap.

Jamie Hall

Before you start, keep in mind that what is in there has run for about 70 years, more or less -- and is still running. Nothing, but nothing, you replace it with will last anything like as long.

OK. That out of the way.

Your best bet is going to be to find out what the circulators run on -- almost certainly 120 volts. Then go and tidy up the circulator and boiler wiring -- especially make sure that the wires are properly colour coded and labelled, and that all the grounds and neutrals are correct an run back to the fuse (circuit breaker?) box as needed.

Then. Put in all new wire and zone control box and thermostats (and transformer, if the zone control box doesn't have one). You may or may not need relays on the output of the zone control box to power the circulators.

swvawethead

Jamie - couldn't agree with you more on the old reliable. Believe it or not the system has been hands-off since we moved in 1996 and I did some tweaking to the piping leading up to the steel tank and made sure the system was properly filled. Recently I finally retired a Series 100 and a multi speed B&G that died with 007s. We hardly know the system is running at times and the convector pipes are 1" instead of 3/4". And we like the simplicity of the old thermostats which we do not mess with often.

Anyway, was looking into this after switching from oil to a Buderus gas boiler next door and using a Taco zone controller with all shiny new stuff. Sure looks more tidy but as you said it remains to be seen on the durability.