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White-Rodgers spdt 11D31 question
FredH
Member Posts: 18
Can a single pole double throw switch be used to control both line and low voltage.
Is there a potential issue with line voltage and 24v on the same common.
I guess I am more concerned with the line voltage toasting 24 volt if both circuits are energized at same time than a 24v back current on the 120v side. I have a good knowledge of electrical wiring but never considered this before.
I want to use switch as a 24 v low lim and line voltage circulator cutout
Thanks
Is there a potential issue with line voltage and 24v on the same common.
I guess I am more concerned with the line voltage toasting 24 volt if both circuits are energized at same time than a 24v back current on the 120v side. I have a good knowledge of electrical wiring but never considered this before.
I want to use switch as a 24 v low lim and line voltage circulator cutout
Thanks
0
Comments
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The answer is
no. The two voltages can't be connected to the common on the SPDT switch. What exactly are you trying to do? A little more information would be helpful.
Typically the SPDT aquastat controls use R to B normally closed for a low limit to operate the burner. Then when R to B breaks R to W makes and is used to operate a low voltage relay to bring in the circulator. The circulator however does not want to come on until there is a call for heat from the thermostat. So R to W should be wired through the relay in series with the call for heat from the thermostat.0 -
White Rodgers Question
Currently it is used as a line voltage cutout for three circulators.
It was set at 120Deg with closed differential.
I think the reason it is so low was was because return water is sometimes close to room temp on call for heat in AM and system would hang if it was a still few degrees above the hi lim differential. Call for heat no circulator or burner.
Just realized that old adjustable American Standard CA-666dt in the tankless well was never breaking( took it out and lubricated and tested and does not break on rise. It was estentially acting as a TT jump and boiler was cycling between hi lim and differential.
Disconnected and now burner and circs come on when call for heat and shut off when call is stisfied. Occasionally will run to high lim.
Hoping to use the SPDT as a low lim and circulator control.
Each circulator has its own thermostat and relay. Not sure if it is possible to put this in series between 3 t-stats and 3 relays.
You did confirm what I suspected. Now if it was a DPDT It would work0 -
Or DPST
will work as you can have 24 volts on one leg and 120 volts on the other leg.0 -
what about buying a White-Rogers 11d18-1?
Reletively inexpensive (about $65) and will serve as inexpensive replacement low limit control on tankless well. Opens on rise and has an adjustable differential.
Line voltage to 3 circulators would remain on its own controller. May not be
the best way but can not figure out how to use one low voltage switch to interrupt three t stats and three circulators. How was that normally done.
0 -
Give me a list of what
you have for equipment and controls and maybe we can sort this out.
Normally if you have a low limit it maintains temperature in the boiler, in the case of a L6006 Honeywell or comparable SPDT from White Rodgers it would be wired (R to into the primary relay on your boiler which typically contains your hi-limit.
When R to B breaks (due to set point temperature say 140° (F))then R to W makes and waits for a call from the thermostat. That will bring in the relay in the primary control and brings on the circulator for that zone.
If there are added zones they would be wired through the primary control to insure high limit protection.
Are you getting domestic hot water from this boiler?0 -
Inventory of existing controls
Contact this user
1964 American Standard Arcoliner wideback with General fittings
tankless (estimated original cap 5GPM) 164,000BTU/hr Becket burner
Hi Limit Detroit Lubricator (Breaks burner line voltage on temp) Set at 185 Deg (Coasts up to 200+ ) Closes at approx 160 Deg
3 taco 007 circulators with 3 American Standard circulator relays with terminals
for TT and SS terminals going to TT on Honewell r8184 G controller on Beckett burner
SPDT American Standard aquastat in tankless well is wired NC(normaly closed) in parralel back to TT on burner relay (however, it is malfunctioning and not breaking on rise
3 luxon programable thermostats (new to replace old Honewell mercury round)
On mid back back of boiler is White Rogers 11d31-1 spdt wired to close on rise (open on drop) to break
line voltage to circulators on temp drop.
Adjustable differential is set to as close
to 0 as possible
It was set set to 120Deg, I bumped it up to 140 deg but sometimes circulators will not turn on and boiler will hang a few degrees above 160 deg diff on hi lim switch on heat call. No burner or circulators. Probably due to cold water return after nightime setback.
Put it back to where it was but boiler was still just cycling between differential and Hi lim.
Dicounected malfunctioning low lim switch and now burner and circulators run until call for heat is satisfied or till hilim and then circulators continue.
17 deg outside with all 3 circulators calling for heat, boiler drops
to approx 130 degs and I still have hot water for shower. Tankless does have
30 gal aqua boost with its own circulator and separate aquastat. Not linked to burner
Hence my original question. Since I can not use the existing SPDT to break line voltage to circulator and also close 24 volt to turn on burner, i was just going to replace the controller in tankless well with a simple break on rise SPST with adjustable diferential. Would act a low lim during off season. Circulators will remain independently controller by own aquastat.
I think that is the way it was setup before tankless controller stopped working.0
This discussion has been closed.
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