Hello. I currently have a Honeywell standard display T-stat. It has only
2 wires connected to the R & W terminals to control my Weil-Mclain steam bo
iler. The T-stat is battery operated.
I have spare wires in my current T-Stat wiring which I would like to utiliz
e to hook up a Wi-Fi T-stat. The Honeywell rep I spoke to in tech support s
aid to put the 2 existing wires to the R & W terminals, and to connect a se
parate 24VAC Power source ( which I have in my basement) to the C & RH term
inals, with all jumpers removed.
Just wondering does this sound correct?
When you get the new 'stat, the installation manual will clearly show
how to hook up that wire. It'll have diagram. I did same with Eco Bee
'stat for my daughter's cabin in the mountain. You don't believe
Honeywell tech support guys?, LOL! I retired from that company after
~40 years. If you ask same question with email they may attach diagram
in reply. Or you can download manual in advance to double check it.
On Mon, 20 Oct 2014 18:32:01 -0700 (PDT), Mikepier
Your stat is operating as a simple 2 pole switch. The Red is 24v in
and the white is "heat call" out. The common is in the boiler.
You could use an unused wire to bring the common to the WiFi
thermostat from the transformer, hook it to C and you are done.
OK, I got it hooked up ,and its working great. But I have a question concer
ning the wiring from my steam boiler. Attached is the wiring diagram. My bo
iler is on page 8.
As you can see on the ladder diagram, The T-stat R wire ( which in this cas
e is terminal G on boiler terminal block) is going through the low water cu
So this means that everytime the LWCO calls for water, which is not often,
the power to the t-stat gets killed because the relay opens up, which I und
erstand this is the way its suppose to work for safety. I confirmed this by
testing yesterday, I drained boiler until light on LWCO kicked on.
Is there any way around this? Not a big deal, but just curious.
On Sunday, November 2, 2014 8:04:44 AM UTC-5, Mikepier wrote:
boiler is on page 8.
nderstand this is the way its suppose to work for safety. I confirmed this
by testing yesterday, I drained boiler until light on LWCO kicked on.
The obvious way around it would seem to be to not wire it in series with th
low water cut-off switch. But I don't understand what the issue is. If th
boiler is working properly, the boiler should maintain the proper water
level. If it's not, then you want the boiler shut off because it's a
hazard, which is what the install intruction wiring would seem to be doing
On Sunday, November 2, 2014 1:57:41 PM UTC-5, Mikepier wrote:
Doesn't it have an automatic fill? And regardless, if the water gets so
low that it triggers the low water cut-off, why would you have an issue
with the thermostat being wired in series with it? It sounds like they
open the thermostat circuit to keep the boiler from firing when the water
is too low.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.