unimatch 24 volt feeder with 2 terminals.. not marked which is hot and which is neutral

Joseph_4

Hi I am working on 2 boilers that both have an old unimatch 24 volt feeder for steam with only 2 terminals.. not marked which is hot and which is neutral. does anyone know which is hot and which is neutral or have wiring diagram?
Thanks
Joe

Ironman

You don't have a hot and neutral with 24V.

STEAM DOCTOR

If I am not mistaken,  the older, 2 wire models, did not have a constant hot. One wire is neutral and one is hot only when there is a call for feed. 

Joseph_4

Im trying to connect the new hydrolevel CG400 LWCO to the old feeder. quoting from instructions from hydrolevel (and Im asking for help cuz I dont want to short out either the feeder or the LWCO) " For water feeders with 2 leads, connect feeder neutral to terminal 2 and feeder hot to terminal A"
Thanks
Joe

STEAM DOCTOR

Is the old feeder still wired? You should be able to manually trace the wires backwards. 

Joseph_4

one of them is... but runs into main power supply then goes into old Honeywell ring LWCO (not so familar with) and has second #67 LWCO so instead of breaking my head I was looking for an easier trip

Ironman

First, do yourself a favor and get a SafeGaurd, not a CycleGaurd.

Second, are you reading the instructions for a 24V model or the 120v model?

Again, there's no hot and neutral on the secondary side of a 24v transformer.

STEAM DOCTOR

See attached. I am assuming that H is for hot and N is for neutral. 

Joseph_4

ok you were right....the wording went to hydrolevel site on 24v model says connect to "feeder common" and the "feeder hot" to terminal A... how do i know which is which?

STEAM DOCTOR

The MM 67 does not have a neutral. All wires running to the 67 are "hot". Not familiar with the Honeywell. Maybe you can post some pics.  

Joseph_4

thats my problem those instructions have 3 terminals how can i make any assumption if control was changed

Joseph_4

here is pic

Joseph_4

ok will be at tomm.. will let u know..

EdTheHeaterMan

STEAM DOCTOR said:

See attached. I am assuming that H is for hot and N is for neutral. 

H on the LWCO is the same as R on a 24V transformer and
N on the LWCO is the same as C on a 24V transformer

They have changed-up the designation to be able to use the C designation for Common on the NO and NC contacts in the LWCO. If you look at the internal wiring of the LWCO, C is common on the switch to B and W

To answer the OP question, Eliminate the wire from H to H on the LWCO to the feeder. Then it won't matter which wire is the B or the N. With only two wires you just need 24V alternating current (AC) since there is no additional circuit to deal with. You can reverse the wires and get the same result.

In the diagram for the Hydrolevel control, just eliminate the wire that I have colored pink.

Joseph_4

Thank you so much Ed.. awesome!! Will implement  today.
Joe