Wiring Diagram for Honeywell R132A Switching Relay


Old 01-02-19, 08:50 PM
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Wiring Diagram for Honeywell R132A Switching Relay

I have a 1950's boiler - American Standard Arcoliner O-153-T - which is controlled by two Honeywell RA832A switching relays connected to two thermostats, a L444A low-limit aquastat, a L4006A high-limit aquastat and a R132A switching relay. I need help understanding the functioning of the R132A switching relay.

The R132A has two sets of thermostat connectors labeled R1 W1 B1, and R2 W2 B2. B1 and B2 are actually the same connector labeled B12. See the attached photo showing the connection diagram from the inside of the cover. I understand that you connect a thermostat to R1 W1 B1. In my case, a two wire thermostat is connected to W1 B1. What is the function of R2 W2 B2 connectors? Can anyone share the internal wiring diagram for the RA132A?

I called Honeywell Tech Support but they had no idea about this switching relay. There are just a handful of online references to this switching relay. None of these references provides a clue as to the function of the R2 W2 B2 contacts/connectors.

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Old 01-03-19, 08:43 AM
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Here's something which may help. https://www.scribd.com/doc/98642688/...cient-Controls
I think it was on page 35
Old 01-03-19, 11:06 AM
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Without being able to trace the wiring, according to your schematic the W,B,R. 2 terminals are used for a limit switch while the W,B,R. 1 terminals are used for your stat or just W & B 1 for a 2 wire stat.

My guess is if you traced that wire you would possibly find it connected to your high limit 4006A possibly to shut the burner down on high limit and keep the pump going if the stat was still calling for heat.

As I said this is just a guess. Your wiring may go from your low limit - to your high limit- to your R132A to your boiler. The three line voltage terminals on the bottom are 1= hot, 2= common, 3= either burner or pump.

If you jump between 1 & 3 I believe either your pump or burner will come on. You could tell better by tracing the wiring.

As I said, this is only a guess going by what I see. Pics of all the wiring would be helpful.
Old 01-03-19, 04:00 PM
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Grady and Spott - thanks for your help.

I had looked at the document you referenced but I only looked at pages 47 and 48 that show diagrams with R132A. The purpose of the R2, W2, and B2 terminals was not clear from these diagrams. Thanks for pointing me to the earlier diagram which is on page 36. This diagram makes it clear how the R2, W2, and B2 terminals function. I've drawn up a diagram of the internals of the R132A based on my understanding. Does it look right?

I'll trace all the wiring on this boiler over the coming weekend and get back with findings.

The reason for this investigation is that I want to simplify the controls by perhaps using a Taco 3-zone expandable switching relay SR503-EXP-4. This controller has R, W, and C thermostat terminals for each zone. This would make it easy to use smart thermostats such as ecobee.

I'll post my findings over the weekend.
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Old 01-09-19, 06:56 PM
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Finished tracing the wiring

So I traced the wiring for the legacy boiler controls. I've attached the wiring diagram. The Americast boiler is controlled by two thermostats and a low-limit and a high-limit aquastat. It has a built-in tankless DHW system (although I don't use this boiler for DHW). The R132A I mentioned above is a legacy switching relay.

Now the next challenge is to redo the entire controls with something like a Taco SR503-EXP-4. The 3rd thermostat input would be connected to the low-limit aquastat. If anyone could help with a wiring diagram to upgrade this system with a Taco SR503-EXP-4, it would be much appreciated.

I want to use the EXP (expandable) version of the Taco switching relay because it comes with the additional Common terminal for every thermostat input. This would come in handy for connecting smart thermostats such as ecobee.
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Legacy Boiler Controls.pdf (94.9 KB, 35 views)
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