Wiring not per diagram


Old 11-18-05, 02:07 PM
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Wiring not per diagram

Ok I'm a bit confused. Just had a new steam boiler installed but it hasn't been working well. Been short cycling ever since it first fired up. Everyone involved with the install, plumber and electrician say that their work is fine.

While reading through the installation manual supplied by the boiler manufacturer. It has this diagram for the electric installation and from what I understand all the electrical stuff should br running of the 24v transformer. Now looking at the electricians installation it is quite different. He has the thermostat running of the 24v, connected directly to the intermittent pilot module and the low water cut-off and pressure switch off of 120v current. How can the LWCO or the PS tell the IPM to shut off? Could this be why it is short cycling? Is this electrician working with his "wires crossed" or am I just not understanding his work?

Can someone shed some light. Should I get the wiring looked at by another electrician?

Pic of diagram
My wiring

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Old 11-18-05, 02:48 PM
Join Date: Sep 2003
Location: Central New York State
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Sorry, I cannot make heads or tails out of your drawing.
Old 11-18-05, 03:29 PM
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Sorry you don't understand. Let me try to explain.
Where all the wires are connected is the junction box. The right top side is wires (black,white) coming from the 120v supply. The lower right are wires (black,white) coming from the Low water cut-off and the lower left are wires (black,white) coming from the Pressure switch. The little box on the left side of the Jnc. box is the 24v transformer. The thermostat is wired directly via the 24v transformer to the intermittent pilot module. The black wire from the supply is is connected by a nut to the black wires coming from the 24v trans.,low water cut-off and pressure switch. the white supply is connected by a nut to the white 24v trans. wire. The white water cut-off and the white pressure switch wires are nuted together. I hope that makes it clearer for you.

Just one simple answer. Is it OK to have the Pressure switch and the low water cut-off running on 120v current?

Old 11-18-05, 04:05 PM
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Is it OK to have the Pressure switch and the low water cut-off running on 120v current?
The quick answer is sometimes. There are switches that are rated for low voltage, switches rated for line voltage, and switches rated for both. It would be reasonable that your switches are indeed rated for line voltage.

It looks like your hots (black wires) may be wired improperly, but the problem I see would not cause short cycling; it would cause the high pressure and low water switches to simply not function. Based on your diagram, it seems like the black from the supply should connect to the black on the low-water switch, and the black from the transformer should connect to the black from the high-pressure switch, but the two groups of black wires should not connect to each other.

My adivce is based on there being no other wiring (high or low voltage) than what you pictured in your drawing. If there are other wires, relays, circuit board, etc then there's more to the story that you need to investigate before making any changes.
Old 11-18-05, 05:05 PM
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Their are no other things inside the jnc. box only those wires shown in my diagram.

The quick answer is sometimes. There are switches that are rated for low voltage, switches rated for line voltage, and switches rated for both. It would be reasonable that your switches are indeed rated for line voltage.
Since the boiler came with all its components in one package and the diagram in the manual had everything running on 24v. I thought that it was the only way it should be wired.

Thx all for your replies. They are most appreciated.
Old 11-19-05, 09:10 AM
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All saftey-controls should be connected to the 120 volt power-supply. With this arrangement, the conductors connecting the saftey controls will be #14 wire ( minimum) rated at 15 amps and 600 volts , and such conductors will enclosed in an approved Wiring Method for maximum protection from mechanical injury.

I consider saftey-controls wired with "exposed" #18 conductors to be an extremly un-reliable. The most important concern is the possibility of a "cross" between 2 wires that in effect will "shunt", or by-pass the saftey controls, and the "Primary control"-- the gas-valve-- will continue to operate and supply heat to the boiler at a time when the heat-input is applied to the boiler in an un-safe and dangerous condition.

A service-man may in-advertantly cause a cross-connection when making an changes to the low-voltage wiring, a possibilty extermely remote when the wiring for the saftey-controls is "Line-voltage" wiring which is "isolated" from the low-voltage wiring.

There was a boiler explosion in a building in NYC that killed 30 people. The saftey-wiring was "Line-voltage", but it was a 220 volt circuit, and when a wire "Grounded", the Primary control remained operated thru the ground-fault even though the pressure-saftey control had opened the circuit.
Old 11-19-05, 12:31 PM
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So from what your saying this is not only wired wrong but dangerous because the safety devices are not going to work at all.

If this isn't what is making the boiler short cycle. Then what could it be? I bypassed the thermostat and wired the IPM directly to the 24v transformer and the boiler still only worked for 4-5 minutes and shut down. The last time the electrician came he said that the IPM was causing the short cycling and that it had to be changed. Waited about a week for the part to come from Utica and it was put in place by the plumber who did the install. Well that didn't change a thing it still behaves the same way.

Any ideas on what could be causing this, if it's not the bad 120v wiring job.

Old 11-20-05, 01:49 PM
Join Date: Oct 2004
Location: USA
Posts: 719
From YOUR drawing I agree the safety devices are not going work.

If this is a new unit, don't you have a warranty?

I think your problem starts with the flame sensor.
It may open up when it gets hot.

A long shot would be the transformer opening up when it gets hot, or the gas valve.
Maybe a second safety item wired with the gas valve.
Old 11-24-05, 12:00 PM
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I put the Tstat at 80 and turned on the boiler at the emergency shut-off swith. She fired up on qeue. I then took my newely bought multimeter and started checking currents. Their was 120vac flowing throught the Pressuretrol and the LWCO. The transformer and tsta both read 25.6vac. The gas valve, as expected, was getting the 24vac it needed to be open.

The boiler worked for about 5mins. and then stopped. I rechecked for current flow. The Pressuretrol and the LWCO were still letting 120vac current flow, so I figure they are workibg fine. The transformer was still letting current flow only now it read 27.1vac. I figure this is because there was no load since the boiler shut down. The tstat was still reading current so It was still calling heat. The connections at the IPM were also ready current. But the gas valve was reading 0 current. It wasn't getting the 24vac it needed to open.

Could it be that the IPM is malfuntioining or is it he flame sensor? The IPM is a UTEC 1003-620A and is less than 3 weeks old. It had been replaced once already because the electrician said it wasn't working right.
Have these models been prone to malfuntioning problems? Are these a good brand IPM or is Honeywell better? Which honeywell IPM would be compatible to this UTEC model?

How do I test/know if the IPM or flame sensor is the culprit?

Thx for the help and Happy Thanksgiving.
Old 12-01-05, 09:08 PM
Join Date: Jul 2005
Location: MO
Posts: 206
Looking at the drawn diagram I see that the saftys are not being used.
(they should be in series as in the manufacturers diagram)
It also shows it being on the low voltage side and not the line as it's wired.

If the boiler is shutting down my question is was the aquastat satisfied??
If not I would try jumping it out and seeing if it runs longer then 5 min. While keeping an eye on the temp gauge.

Like i said before your lwc and ps are not being used at this time. (this is very unsafe)

With electronic ignition and controls your unit ground is very important. I have run into a few calls that the ground was lose and caused problems.

Do you have the book on the unit? Or does the cover have a flow chart for trouble shooting? If not go to the boiler mfg website and see if they have a flow chart, or the honeywell web site.

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