Old Coleman mod 3110-750 heater only

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richnchicks
Posts: 7
Joined: Sat May 16, 2009 10:54 am

Wed Sep 10, 2014 4:52 pm

I am helping a friend fix a furnace that had 2 parts taken out. One is the transformer and the other is the quick disconnect. I am having a problem finding the parts for them. The code serial number is 67664471. the model is 3110-750. btu is 33,450. Disconnect number on casting is 13484. Any help will be appreciated. It was supposed to be working before the parts were scavenged for another heater. All components look good. Maybe this will help, on schematic,yellow wire from transformer goes to fuse terminal #1, orange wire goes to fuse terminal #4, red wire from transformer goes to thermostat and black wire goes to h2 terminal on sequencer. H1 terminal on sequencer goes to thermostat. M1 and M3 yellow wires on sequencer go to fuse terminal #1. M4 and M2 wires from sequencer go to elements and M2 black wire goes to blower motor. Common terminal on blower motor goes to fuse terminal #4 orange wire. That is the entire wiring schematic! Got to love old stuff! Looks like transformer had foot mount. See if I have this right, it seems the only things the transformer powers are the thermostat and the sequencer. The data plate says 240volts which would be 240v into transformer and probably 24v output if that is what the thermostat and sequencer use. The va (volt amperes) on transformer would only need to be big enough (or bigger) to power those two items. So, would a 240/24v/40va transformer work or is it too much va? An update, the sequencer is 24 volts and the thermostat is a 2 wire. My understanding is that too much va is okay but too little is bad. So, a 3300-3861 transformer should work. Also, the sequencer looks like the 3110-3571.


jpingram5
Posts: 205
Joined: Sun Dec 05, 2010 5:34 pm
Location: Orefield, PA
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Fri Sep 12, 2014 9:09 pm

What is the one you are replacing? Is it 20va? I believe it would cause a problem such as over heating.

What I'm trying to say is that it should work for a temp solution but I'm pretty sure if it's that big a difference it will end up dying rather soon.
2009 Skyline Sunwood Premier 14 x 80

richnchicks
Posts: 7
Joined: Sat May 16, 2009 10:54 am

Fri Sep 12, 2014 11:21 pm

The old one is gone. It is one of the two parts that were scavenged. We never saw the old one. I would imagine a smaller one would be good since the only thing it will drive is the small sequencer and thermostat but, if it is too small it will burn up, too, right? Since the va (watt rating) is the only question, now that I found the 24v on the sequencer, It seems it comes down to what load the sequencer and thermostat will draw, if I'm understanding it right. Will the sequencer draw an unlimited amount of watts when it has a call for heat from the thermostat? This is the part I don't understand yet. Or, does the va limit the draw to keep from the overheating condition you are talking about. I honestly appreciate all your help and instruction. Thank you.

richnchicks
Posts: 7
Joined: Sat May 16, 2009 10:54 am

Sat Sep 13, 2014 12:04 am

A note for Robert. Back in 2009 I rewired the heater in my old house with your help. Just wanted you to know it is still working perfect and has not had one problem since. We have bought a new home since and my sister-in-law is living in the old place. Thanks again for all your help.

richnchicks
Posts: 7
Joined: Sat May 16, 2009 10:54 am

Sat Sep 13, 2014 11:12 pm

Let's try this, I have,
9.6 kw element =33,450 btu 40 amp
blower motor 1/4 hp, max mtr FLA=2.5
new 2 wire thermostat.
24v sequencer 2 stack for motor and elements only.
240volt system
No a/c on this heater.
What is the proper transformer va rating I should be using? 240/24/ ? va
thanks.

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