Electric boiler operation

Bob Larson_3

I'm working on a 60 year old New York electric boiler. I replaced the aquastat relay, and it's working again. But when I started it up, only one element came on. It's heating slowly, but I can't for the life of me figure out how the elements are sequenced? It's just controlled by the 24v control circuit in the relay as far as I can tell. Is there another control that I'm missing? I'm concerned that when the weather turns colder, one element won't keep up. I have continuity thru all 4.

EdTheHeaterMan

Is there a wiring diagram?   

Or a model number that we could use to find a wiring diagram?

Bob Larson_3

Here's the info

Bob Larson_3

The wiring diagram on the boiler only showed the 24v control circuit and nothing else. But I didn't take a pic of it.

Zman

Some sharper pictures would help.
Did you check voltage or amperage?
Did you Ohm the coils or just check continuity.

Bob Larson_3

Voltage was fine. Ohms were around 15 if I remember correctly.

hot_rod

Loops a lot like the EFM boilers, maybe a private label. Should have a step or time delay control.
https://cdn.efmheating.com/eb4-Manual-Orig.pdf

EdTheHeaterMan

Looking at @hot_rod 's post and other brands of electric boiler, they all seem to have the same components and your second stage of heating elements should come on by way of a 2 pole contactor connected to a time delay relay or a sequencer. So you either have a bad time delay if the contactor is not pulling-in or you have a bad contactor if the contactor is not pulling in or if it is pulling in and the elements are not energized.

If we could see the areas indicated on the picture it would be helpful

Bob Larson_3

Thanks, Ed. I haven't been back to that job since Saturday. She says it's working fine. I'm just concerned that may change when the weather gets colder. It may be that there's no problem.

Bob Larson_3

So I went back today and the sequencer has been fried. Is this something that they even make any more?

Solid_Fuel_Man

Looks like the micro switch can be replaced. 

Im not familiar with the sequential operation of the 4 elements. 

Looks like there are only 3 connected. You could replace the sequencer with two contractors, and a time delay relay. Or if you have an extra conductor to the thermostat or can pull a new thermostat wire. Install a 2 stage thermostat to operate the two pole contactors.

Stage 1 would be 2 elements, and stage 2 would be the additional 2 elements (all 4 energized). 

EdTheHeaterMan

You may not be able to get an exact fit. You can make it work with aftermarket parts. You need to know how the electric parts work to do it. Not an easy thing to do unless you are experienced in this type of thing.

You knew enough to realize that not all the elements are powered. Take a look at the diagram Hot Rod Bob Rhor sent you and compare it to your diagram. There is a time delay for the second set of contacts. Maybe you could eliminate the defective sequencer and replace it with a contactor and a time delay available from any HVAC supply company.

The section on your diagram (Part 36E5) that is bad could be replaced by 2 contactors and 1 time-delay relay.

https://www.supplyhouse.com/Packard-C230A-2-Pole-Contactor-24V-30-Amp

https://www.supplyhouse.com/MARS-32391-Adjustable-Delay-on-Make-Time-Delay

hot_rod

pretty sure parts are still available for that or a very similar boiler. EFM = Electric Furnace man

Bob Larson_3

Thanks everyone for your assistance! I will be able to give them options.