Purge light flashing on Lochinvar boiler

Dave_61

we have a Lochinvar EBN300 boiler. It has been nothing but trouble with lockouts, etc. This morning....no heat again. The purge light is flashing (can be fan switch fault, etc). The last time this happened, it was the flow switch. I shorted the terminals on the flow switch, but boiler wouldn't fire. Fresh air fan appears to be running.

Now, after not running all night, boiler came on on its own.

Does anyonr have any ideas as to why this would intermittently be not working?

Thanks.
Dave

Rob L_3

Could be

The venting arrangement? If the flue switch does not prove then the boiler does not light. Or a bad hot surface ignitor? We have used these boilers before and usually if all it does is trial for ignition but never light it is usually one of the above.
If not, call the techs at Lochinvar for assistance, they should be able to help further.

Rob

Dave_61

This has been a recurring problem

for us over time. It is direct vent with fan that brings in fresh air.

Over the years (at least once a year), the service people have replaced the air-proving switch, ignitor, circuitboard. They have also cleaned the burners and adjusted the air shutter. The last time, it was our flow switch in the boiler water piping was not closing.

I shorted the terminals on the flowswitch this morning and boiler would not start.

The normal sequence is:
1 Power light comes on
2 Purge light comes on and then switches off when ignitor lights.
3 Valve light comes on (gas)and burners ignite.

Currently, the power light does come on, but the purge light does not come on....then the boiler tries over and over and finally gives up. Then the purge light flashes.

I'm at a loss. Then, later this morning, the boiler is on....came on by itself. But dollars to doughnuts, it will not be working tomorrow morning.

Is there a way to test the air proving switch....eg short out terminals with jumper wire to see if it works?

I wouldn't think it was ignitor because we don't get to the ignitor phase.

Rob L_3

You can

Test the ignitor at room temperature(it cannot be warm) for resistance ohms and I believe it should be 40-80 ohms on a good(cool ignitor). You can also try jumping the air switch or just push in the diaphragm with something.

Yes, these boilers seem to be very picky and for some reason have a very narrow window of that happy place where it lights consistently. It will come down to what electrical circuit is not proving as this seems like an electrical problem and not a combustion problem.

Dave_61

Thanks Rob.

So the ignitor could be faulty even though the purge does not seem to finish (ignitor LED never lights).
I actually bought a freeze detector that will phone us when we are away as I am so paranoid about this boiler. We have had maybe 5-6 lockouts since '01 (when it was new).
Any possible connections on circuitboard that could cause this....like when we had our flowswitch across X/B not making?

Stirling Boston

Let's talk, please call

I'm confident that we can help you with this.
please give us a call at 1-800-722-2101. Any one of us that answers will be able to help.

hvacfreak

Dirt

At least on commercial units....the air tubes in the burner assembly have very small holes that pass air. When these get clogged the inducer can't move enough air for combustion and the air switch locks out everything. Remove tubes and rinse each one with water ( and replace the burnt ones ).

Dave_61

Well,

the gas co guy came today as we have a maintenance agreement with them, and God knows we get our money's worth.

He says he ran the boiler through 15 cycles without one lockout, so he will be coming back tomorrow to replace the circuitboard/control board.

They also did this last year....does that make sense?

Last fall when we had another nuisance lockout (happened to be a flow switch that was not closing), they removed burner tubes and cleaned them, and none were burnt.

hvacfreak

wishful thinking

From my experience with the larger units they are just very sensitive to the ammount of air that needs to move through. And after seeing those tubes , I'd think that the unit needs to have an air filter installed all the time ( the newer ones have a filter rack on the air inlet ).

Inducer blower wheels were something else I had to clean often. As sensitive as these are , I'd say " CLEAN " is the key. Everything on these units needs to be CLEAN , including the cabinet and EVERYTHING.

And draft spikes or something....I'd say they'd cause a lockout in a second. I've never had draft issues on the new ones I've started up , but as sensitive as thoses switches are I'd say that any resistance whatsoever would cause sensed failure. Any windy days lately ?

Dave_61

We have a service contract

with the gas co. The guy came yesterday and ran it through its paces (15 cycles without any problems). The boiler ran fine all last night. This morning....no heat or hot water. All zone pumps running. Boiler flashing "purge". If I had a 44 magnum, that boiler would have about 20 holes in it.
Why would it work fine all afternoon/evening but not fire at night? It must have been off all night because our Phase III hot water tank was cold also.

Joannie_15

The Service Guy

Your service guy needs to talk to someone at Lochinvar. Sounds like he's guessing. Lochinvar posted a phone number. Maybe you should give the service guy that phone number when he comes back.

Dave_61

You'd think

they'd use it...I've given it before, but they feel they can do this themselves.

Rob L_5

\"Doing it themselves\"

Is costing you extra money that could wisely be spent elsewhere. I seriously doubt control board is the culprit in this scenario and does not need to be replaced. Make them call the tech guys at Lochinvar and stand there while the do it. A technician that guesses at what the problem "could be" and then replaces parts based on that guess is doing you a disservice.

Dave_61

Well,

the serviceguy came yesterday and cleaned the burner tubes as well as replaced the controlboard and the pressure switch. Since we have a service contract, it cost $0.00. And so far, the boileris running for >24 hrs!!!!