Boilder is not starting...

Kh500

Boiler is not starting.

Peerless residential steam boiler on natural gas, installed 1991 and flushed and cleanned early this year.

I tried;

- Replaced old thermostat to new simple non-programmerable Honeywell thermostat, There are only red and white wall coming out of wall to connect.

Red and white wire is marked by looking at old thermostate mountboard and re-connected to new one.

- 15A socket fuse replaced <ol><li><a href="http://i183.photobucket.com/albums/x130/kh500/boilder/boiler074.jpg">http://i183.photobucket.com/albums/x130/kh500/boilder/boiler074.jpg</a></li></ol>



How do I proceed to toubleshoot for non-start issue?

Thanks in advance.

David Nadle

Check the LWCO

Maybe the float on your low water cutoff is stuck. Isolate it from the circuit and see if the switch is open or closed.

BobC

Won't start

If you have the boiler manual and a voltmeter you can go through the wiring diagram and see where the power stops. If the thermostat is good the two safety's that will lock the system off are the LWCO and the pressuretrol.



When pressuretrols get iffy sometimes the switch inside doesn't close and will prevent the system from starting. Go through all the wiring to make sure something isn't just loose or corroded. just be careful so you don't get lit up.



Bob

Kh500

l

Thanks for suggestion.

Low Water Cut Off swithc has been working intermittently last winter.

When I had a flush and cleanup, literally mud came out.

The boiler was installed in 1991 but the previous owner never really maintained it seems when I moved in this year.

Kh500

i

Thanks for advise.

I should look up the manual wire diagram.

How do I check pressuretrols?

BobC

Pressuretrol

The pressuretrol will open the circuit when the boiler pressure goes above the set-point (usually 1-1/2 or 2 PSI), when the pressure falls below the differential (usually 1/2 PSI) the switch will close and allow the boiler to start.



On the front of the pressuretrol you will see a screw that will allow you to remove the cover, inside you will see the switch with two wires leading to it. If the boiler has been off long enough for the pressure to drop off the switch will be closed and there will be no voltage across it.



BTW sometimes just a good rap with the plastic handle of screwdriver will cause an intermittent switch to close, when I was a tech at the post office I fixed more than one switch by doing that.



Bob