flue damper relays

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ronball

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Location
Champaign Il.
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Electric Contractor
inspector says we have to connect relays up to 3 water heaters and 3 furnace boilers to turn on exhaust fan when any are running. ( a 3 phase fan)
any help on installing would be great/ or a diagram. Ron/ central illinois
 
Put a relay coil across each appliance's load side of whatever controls it, so it comes on with the appliance, and run a 2-conductor wire from relay to relay.

Connect these wires in parallel to a N.O. contact on each relay, and connect the other end to the fan controller. Now, if any appliance fires, so does the fan.
 
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Larry, are you saying that you could install one contract on 1 phase of each 3 phase point of usuage ?

I've seen it mentioned here before that dropping a phase is considered "control wiring" , granted your just looking for current flow and not dropping nothing!

Lets expand the OP and state that is a 6 branch service situation only motors and fans in this can, wouldn't a doughnut on the Line side work or this would not be cost effective, or just plain to much ?

I don't know, I'm just asking ?
 
flue damper/ gas usage

flue damper/ gas usage

any help is appreciated. the inspector wants the make up fan to come on when any gas appliance is in use. 3 water htrs. 3 boilers. is their any way to monitor gas flow / or do we need to use damper control . Ron
 
Larry answered, LOL I missed "relay coil", Doh...

If you address the gas then call a plumber, can't you also tap off the tempertute of the control board of the boiler or interface or use a therostat in any case?

:wink:
 
The inspector will probally also want an interlock to shut off the water heaters and boilers if the fan fails,or at least an alarm. I know I would, incredible liability there if the fan fails and tennants die of carbon monoxide poisoning. A sail switch or pressure differential switch should work.
 
ronball said:
the inspector wants the make up fan to come on when any gas appliance is in use. 3 water htrs. 3 boilers. is their any way to monitor gas flow / or do we need to use damper control .
Click to expand...
This is the first mention of them being gas appliances.

Okay, you need a way of closing a pair of contacts triggered by each appliance firing up. The rest is easy.
 
The water heaters may be a little more difficult, as a lot of the lower efficiency types use a thermocouple to control the gas valve, so the control cannot be intercepted. The OP did not state what type these were, But since there's three phase available, I would say that there not of that type, but large commercial type.
 
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