Adding a zone to Burnham V73 Oil Furnace boiler

jweggy

Hello,

I have a Burnham V73 Oil Furnace boiler with three zones providing hydronic baseboard heat and domestic hot water with a superstor tank.
The two hydronic baseboard heat zones are connected with the following Honeywell devices.
- Honeywell R845A switching relay.
- Honeywell L8148A aquastat relay.

The domestic hot water zone is connected with a Taco SR501 switching relay.

As far as I can tell the Taco SR501 relay is wired into the Honeywell R845A switching relay with the DHW circulator feeding downstream from the circulator controlled by the Honeywell R845A.

***I am planning to add another hydronic baseboard heat zone and was wondering if I could use the (ZVC404-EXP-4) Taco 4 zone valve control module with priority expandable to replace my current setup? The baseboard for the far end of the new setup is already in place.

Robert O'Brien

First thing I would do is take off right side jacket panel and make sure that thing isn't leaking, it sure looks like it

jweggy

Thanks for the tip. I have checked and have no leaks. The moisture on the ground is from a failed durastill that is being removed this weekend!!

lchmb

zvc is a zone valve control not circ's.. that would be an sr504 exp. Does your boiler maintain temp or is it allowed to go cold?

HVACNUT

Where is the third circ?
Like @lchmb said, you need an SR504 for circs. Why the EXP, unless your going to expand again?
Wire all the zones into the 504 using zone 4 for the indirect on priority.
Use dry contacts XX in the 504 to TT in the aquastat.
Looks like everything on that system has seen better days, and has exceeded their life expectancy. You might be throwing good money after bad. Burner motor, primary, fuel pump, circs, tridicator, furnace cement holding the inspection door on, black on the jacket above the front plate. What does the chamber look like?
It's probably time to think about upgrading to a new system.

jweggy

The 3rd circ. is near the DHW heater.

What do you think it would cost for a total replacement?

HVACNUT

We don't discuss pricing here, but if you click on the link at the top of the page "Find a contractor in your area", you'll get responses from the pros.