Remove and Replace Old White Rodgers Zone Valve on Boiler

MitchAgainN8

I have an old boiler system with two white rodgers 1311 zone vlaves. These connect to mercury thermostats with three wires and work on power open / power close.

I am trying to replace the mercury thermostats with wifi thermostats but am encountering problems with this type of series 20 wiring. What I want to do is replace the old power open / power closed zone vlaves with different vlaves that will work with the new thermostats.

I don't know which vlave to use as a replacement and how to install it. Any suggestions?

HVACNUT

What model thermostats?
Most can use the O/B terminal to power close.

MitchAgainN8

I have the ecobee smart thermostat... So you're suggesting wiring the y wire from my mercury stat into the ob on the wifi stat...

mattmia2

Could always use a spdt relay as well

MitchAgainN8

The spdt relay is the next thing in going to try. My main concern with that is failure... Worried that a relay might fail every couple of years...

mattmia2

The relay has very little load on the contacts and a lot less moving parts than the zone valve.

I would be far more concerned with everything about the ecobee.

hot_rod

Are you wiring via a relay box? At least 3 wires at the t-stat location? Ecobee work fine with 3 wires and a typical power open zone valve.

HVACNUT

I would contact Ecobee.
I dont see anything in their manual for series 20 wiring.
The Honeywell stats use W and O/B.

MitchAgainN8

I'm also considering just swapping out the zone valves. Can I use any zone valve or do you recommend one to replace the white rodgers 1311?

hot_rod

Any zone valve should work. Spring return are the most common. Numerous brands available
The Caleffi Z one has a 5 year warranty is you install it with a Caleffi ZVR relay box. This would solve the valve and wiring issues and work with any of the WiFi stats if you have 3 wires at the stat it will be a simple Install

https://www.caleffi.com/sites/default/files/file/01115_0616_na.pdf