Wiring up a Taco 007-F5 circulator

shortmort37

I'm wiring up to a Rheem Prestige combi, and the connection inside the box is tight, with no provision for strain relief. 18 gauge lamp cord is rated at 5A, and the circulator is rated at .7A (the combi will supply a max of 2A). Would I be ill-advised to use lamp cord? I would, of course, use a standard junction box clamp at the circulator with a rubber grommet.

bucksnort

No

MikeAmann

You need the proper wire. There is more to wire than the gauge and current capacity. The insulation is a factor also. What the device connected to the end will draw for current UNDER NORMAL OPERATING CONDITIONS is not the only consideration. Suppose the device shorts out. Your circuit breaker at your electrical panel is 15 amps. You need that wire to be able to carry that >15 amp current to trip that breaker. So what could happen using the 5A rated lamp cord under a not normal condition? Your lamp cord heats up, melts the insulation off, exposing more bare (electrically) HOT wire that can now melt into other wires and/or short out with them, or anything else. A fire could start. And the breaker back at the panel has no idea that there is a problem, so it does not trip. You still want to use that lamp cord?
Go to Home Depot or Lowes and buy a foot of the correct wire.

EBEBRATT-Ed

No. And you need 3 wires Hot, neutral and ground. You can use solid or stranded #14 wire (stranded is easier to work with) The hot can be any color except for white or green, The neutral should be white and the ground green or bare but I would use an insulated ground.

You can use greenfield or seal tight

shortmort37

OK; so I'll use 15A wire with a ground for the external Taco pump. Here's the diagram I have to work with:

I can take the ground wire and connect it to the enclosure. When I do that, the pump is no longer isolated from ground; meaning, the polarity of the hot/neutral connections to CN17-1/2 becomes important. But the diagram is not color coded. When I called Rheem tech support, they couldn't identify which was which; they said use a zone controller to power the pump. Which, makes sense if you have more than one zone. I don't.

Is there anyone out there who has wired up an external pump to a Rheem Prestige Combi boiler, using CN17? My fallback plan is to enable the terminal in Installer Mode, and check the terminals with respect to ground to identify the hot terminal.

EBEBRATT-Ed

Power up the boiler. You have terminal #1 (the power into the boiler) which is HOT
You have Terminal #9 which is the incoming neutral

Terminal #1 for your circulator is probably HOT Check this by putting a meter or test light between both #1 terminals (incoming power and pump terminal) you should red 0 volts when the boiler is calling the pump to be on. Both these terminals will be HOT but you will read no voltage between them. Check each 1 terminal to ground or to the # 9 (neutral) and you should have 120 volts.

#2 is probably the pump neutral connection. You shold have 0 volts between #2 & #9 and 0 volts to ground from #2 & #9

EBEBRATT-Ed

I looked in the Noritz manual. They don't tell you about the polarity of the external pump.


And they should that is crap.

And they do not show it grounded which it must be grounded (although they do mention it has to be grounded.)

They do say the pump can't draw more than 2.0 amps. If it does then use a RIB relay #RIBU1C with the coil connected to 1 & 2 (pump terminals 120 volt) and the pump wired from terminals #1 & #9 (incoming Power) with the RIB Relay NC contacts between #1 incoming power and the pump hot wire. Run the neutral from #9 to the pump

shortmort37

EBEBRATT-Ed said:

I looked in the Noritz manual. They don't tell you about the polarity of the external pump.


And they should that is crap.

And they do not show it grounded which it must be grounded (although they do mention it has to be grounded.)

They do say the pump can't draw more than 2.0 amps. If it does then use a RIB relay #RIBU1C with the coil connected to 1 & 2 (pump terminals 120 volt) and the pump wired from terminals #1 & #9 (incoming Power) with the RIB Relay NC contacts between #1 incoming power and the pump hot wire. Run the neutral from #9 to the pump

I see. So, isolate the pump with a relay. Since the input power to the unit comes from a junction box, I'll run a line from that to another box to which I'll connect the relay, and make up to the pump from there. I would use the NO contacts of the relay to feed the hot side of the pump, correct? Which would close when the relay is activated by the pump terminals in the Combi? Any recommendations for wire from these terminals to the relay? There won't be a ground wire.

EBEBRATT-Ed

Not saying you have to use a relay but the 2.0 amp limit is rather low that why i suggested a relay. #14 wire just run a ground with the pump feed. Relay coil get pulled in from Combi

hot_rod

Certainly no harm in using an isolation relay, but that Taco will work fine powered from the onboard relay.
Or use the 007E, ECM type circulator for even less power draw.

shortmort37

hot_rod said:

Certainly no harm in using an isolation relay, but that Taco will work fine powered from the onboard relay.

Understood; but in the absence of isolation, I need to know which of the CN17 terminals is hot, and which is neutral. No biggie - I'll enable the external pump, call for heat, and measure each with a meter with respect to ground. Then, agreed, I can dispense with the relay.

pecmsg

14 gauge
seal tight
or
MC cable

hot_rod

pecmsg said:

14 gauge
seal tight
or
MC cable

The box store sell short pieces of BX, 8 feet of # 12 is about 12 bucks with two connectors.

ethicalpaul

MikeAmann said:

Your circuit breaker at your electrical panel is 15 amps. You need that wire to be able to carry that >15 amp current to trip that breaker. So what could happen using the 5A rated lamp cord under a not normal condition? Your lamp cord heats up, melts the insulation off, exposing more bare (electrically) HOT wire that can now melt into other wires and/or short out with them, or anything else. A fire could start. And the breaker back at the panel has no idea that there is a problem, so it does not trip. You still want to use that lamp cord? Go to Home Depot or Lowes and buy a foot of the correct wire.

Doesn’t the same concern exist when using the lamp cord to wire…a lamp? So UL is endangering everyone by certifying lamp cord?

so if you have a 20 amp line with a 20 amp breaker everything you plug into it must be able to carry 20 amps?

ChrisJ

ethicalpaul said:

MikeAmann said:

Your circuit breaker at your electrical panel is 15 amps. You need that wire to be able to carry that >15 amp current to trip that breaker. So what could happen using the 5A rated lamp cord under a not normal condition? Your lamp cord heats up, melts the insulation off, exposing more bare (electrically) HOT wire that can now melt into other wires and/or short out with them, or anything else. A fire could start. And the breaker back at the panel has no idea that there is a problem, so it does not trip. You still want to use that lamp cord?
Go to Home Depot or Lowes and buy a foot of the correct wire.

Doesn’t the same concern exist when using the lamp cord to wire…a lamp? So UL is endangering everyone by certifying lamp cord?

so if you have a 20 amp line with a 20 amp breaker everything you plug into it must be able to carry 20 amps?

Yes,
And I've never seen table lamps wired with 12 gauge wire.

Also, refrigerators, freezers etc are often wired with 18 gauge wire internally as chassis wiring rules are different than NEC rules for wire buried in walls. The NEC rules also include a huge safety factor.

18 gauge wire is actually good for 16 amps for "chassis wiring" according to most charts, but it'll run warm. Obviously you need to take voltage drop into consideration.

It's also common to install 15A rated receptacles on 20A circuits as it's assumed there will be more than one in use at a time.

MikeAmann

Thank you @ChrisJ
What he said.

EdTheHeaterMan

This was a very enlightening discussion. I got a charge out of it. I just want everyone to know that many of my customers are shocked to find how little I know about electricity.

Incorrect diagram removed. Also the reason for the last line in this comment

This should work for you!

To be 100% sure follow the instructions @EBEBRATT-Ed listed above.

shortmort37

Was this diagram markup just a guess on your part? If so, you guessed wrong. I just now got around to measuring with my VOM, in preparation for the work to be done. Terminal #2 is HOT with respect to ground with the external pump enabled, and calling for heat; not #1. Correcting for the record, lest someone else wire things up incorrectly.

EdTheHeaterMan said:

I just want everyone to know that many of my customers are shocked to find how little I know about electricity.

OK. I can agree with that.

EdTheHeaterMan

@shortmort37
An educated guess, It has always been my experience the No1 terminal is always HOT and No 2 terminal is always Neutral. on most controls for ~115V. HVAC controls. This company must want me to re-educate my guesses.

Sorry for the confusion here, Thanks for the followup I will remove the incorrect illustration.
Also the reason i indicated to follow EBEBRATT-Ed' instructions

Second time I remember wrong... Ask me about the first time!

Solid_Fuel_Man

@ethicalpaul and @ChrisJ

The NEC is concerned with permanently installed wiring. So yes, a 15A breaker which should be protecting the boiler circuit then all wireing that isn't otherwise brotected by a secondary overcurrent device should be rated to handle the full 15 amps. 

I completely understand the sentiment about the 16 gauge lamp cord, and I've made the arguement before the NEC about requiring fuses installed in the cord end like we now have with Christmas lights. Cheap solution, but instead they believe Arc Fault breakers are adequate. As an electrician fuses are always superior.......

ChrisJ

Solid_Fuel_Man said:

@ethicalpaul and @ChrisJ

The NEC is concerned with permanently installed wiring. So yes, a 15A breaker which should be protecting the boiler circuit then all wireing that isn't otherwise brotected by a secondary overcurrent device should be rated to handle the full 15 amps. 

I completely understand the sentiment about the 16 gauge lamp cord, and I've made the arguement before the NEC about requiring fuses installed in the cord end like we now have with Christmas lights. Cheap solution, but instead they believe Arc Fault breakers are adequate. As an electrician fuses are always superior.......

Are these pumps protected by a secondary overload device?
I guess my Taco 006 is just fine as it's connected via a NEMA 5-15 plug so that's considered temporary.

P.S. fuses won't make a good electrician. I think they'll just lay there ant not get any work done.

HVACNUT

Terminal 1 has been the hot terminal on a switching relay since the beginning of time.
Terminals 1 and 3 are jumped by the manufacturer. Terminal 2 is neutral. Always was. You've got some funky wiring. 

shortmort37

HVACNUT said:

Terminal 1 has been the hot terminal on a switching relay since the beginning of time.
Terminals 1 and 3 are jumped by the manufacturer. Terminal 2 is neutral. Always was. You've got some funky wiring. 

Terminal 3? 3/4 are a 24V AC input, if you refer to my original diagram. I'm not sure why you are bringing this into the conversation.

At any rate, the VOM doesn't lie, funky or not. Funky, you can take up with Rheim. My only point is that one should never assume, because you know what they say about assume...

I used BX, per recommendation of others in this thread. The Taco is wired up with neutral to terminal 1, hot to terminal 2, grounded to the Combi enclosure, and operating admirably on this chilly night.