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#19095 - 12/19/02 04:42 PM Thermostat wiring to gas boiler
BurnOut Offline

Registered: 12/19/02
Posts: 10
Loc: Long Island, NY
Hello everybody

I've been checking out this site for a week now and see alot of knowledgable people posting here. So I thought I would ask a question to get a answer from some pros. Since the last time I did any wiring was in high School 7 yrs ago.

It may seem basic but I can't seem to find any good reference on the internet on thermostat wiring. I never can figure out who this falls under plumber/electrican, but here goes

My house is a 2 wire thermostat 3 zoned gas boiler for reference

1) I read the thermosat zone value insturctions and it said that the wire type is suppose to be 18 guage, low and behold the basement and second floor have 14/2 wiring instead(I hope I used the right terminology here ack). I've replaced the basement to an 18 guage themostate wire from the thermostat to the zone valve, and the 1st floor too because it's all rotty. Still have yet to replace the second floor wire.

2) The electrican that did the work last, left a whole tangle of thermostate wires with wire nuts tied up to a nail on a board next to the boiler, I am assuming that this is totally sloppy? I know there must be a better way of wiring it up than that.

3) I also notice that the emergency kill switch for the boiler is spliced to the cable of the the boiler inside the circuit breaker box. I thought the correct way was to do that in a junction box?

4) should the cable running from the breaker box to the boiler be armoured or conduited entirely for that distance? Because there is armoured cable from the boiler to a junction box, then from that junction box is a conduit and out of the counduit is that old tar paper wire to the breaker box.

5) does honeywell purposely make those 8043v motors on the thermosate valves burn out every 4-5 yrs? I've asked a few other homeowners and they all seem to have that problem too.

Sorry for all the questions, and for not having some pictures as references. But after reading the posts and lookng at the violation pictures, it got me snooping around my house.

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#19096 - 12/19/02 05:04 PM Re: Thermostat wiring to gas boiler
Wirenuttt Offline

Registered: 11/10/02
Posts: 267
Loc: Massachusetts
Sounds like your house is around 50 years old or so.

Q#1:I like to run 18/3 wire minimum, you have an extra line in the jacket for future or if one of the lines break.

Q#2: I like to use 3/8" flexable metal conduit around boilers and fasten them appropriately. Sleeving the thermostat wiring to control boxes. On the zone valves I take a ball point pen, wrap the t-stat wire snuggly around it. Makes a shock whip, looks like a short telephone cord when your done. I make these about 4-6" long just before connecting to zone valves.

Q#3: I don't know your local electrical code or fire department codes but mostly I run a feed from the panel to kill switch then to the boiler. The switch should have a gas boiler switch plate thats red at the last or first door before entering the boiler room or basement. I also install another switch on the boiler itself for servicing. This is a gas system so no fire-o-matic is nescessary.

Q#4: When applying the feed to the boiler run emt up to the ceiling and make a 90 degree bend, bring the conduit away from being directly over the boiler and acssesable.

Q#5 I'm not sure of this honeywell item.

I know mostly that circulator pumps are better than zone valves.

#19097 - 12/20/02 02:52 PM Re: Thermostat wiring to gas boiler
Gwz Offline

Registered: 04/29/02
Posts: 199
Are you sure it is a Class 2 system as opposed to a Class 1 system ?


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