I have an oil fired Weil McClain boiler, vintage 1974ish, tesco burner which I was told is the same burner as a becket hi retention head. 3 zone valves 2 for heat (upstairs and basement) third for indirect hot water tank. 2 digital thermostats Honeywell aqua stat which is brand new.

2 years ago on occasion I would hear my boiler run its normal cycle, it would start smoothly run its cycle. When it would shut down at end of cycle I t would immediately come back on and shut down a second later. It would stay off until heat or hot water was called for. Sometimes it would do as described above, other times it ran fine. The boiler was cleaned and could not duplicate the problem when tech was hear. He told me it could be relays in aquastate vibrating and week. The aqua state I have is expensive.
Last March I had no heat, if I pushed reset button heat would come on. I changed aqua state $505.00 from heating supply house. Boiler started working fine but would still occassionally hear it shut down at end of cycle, restart for a second and shut down again.
Boiler since then has gotten worse during the cycle now it will go on and of during the heating cycle. It wil run 2-4 minutes go off and on not really shutting down but sputter several times, run fine sputter, it seems to stay lit.
It got so bad that it finally stopped running last month. The aqua state relay would click on and off to a point it no longer fired. It was the circulator relay giving me the problem. I took aqua state back under warrantee, got another one, installed it. Everything was fine for a week. Now I am getting the sputtering during the heating cycle again. It is not shutting off, just sputtering sort of dieting out and catching again, were do I go from here.

 

Going to be a hard one to trace.
I would set myself up so that I can short the TT right at the aquastat on the boiler.
When it starts to sputter and do it's thing at the end of the cycle, you can short the TT and see if it still does it, or if the burner fires properly. Then try it again, but this time open one of the wires that goes to the boiler TT from the zone control box. If it still sputters and runs on, then at least you have ruled out the zone panel, or vice versa if it stops running on then you can safely assume that it's something in the zone wiring.
good luck

 

You got the optional GOLD PLATED model I presume?

What is the model of the AQUASTAT ?

 

The aqua stat ( autocorrect sucks) is a Honeywell R8182h-1070/1088. Last year cost 529.12

 

The end of cycle shut down start up is no longer an issue. I was giving the history in case it would help diagnose the problem I am currently having. The issue now is sputtering, I changed filter and screen, befor changing these items I blew out the supply line at the pump into the oil tank. I heard bubbles inside the tank. Put it all together started it up and it went through a cycle fine. Just took a shower and boiler came on ( indirect hot water tank) boiler came on ran after 3 minutes or so starts to sputter. How can I trouble shoot this problem.

 

You mentioned it was cleaned, but when was the last time a complete tune up was performed?
New nozzle, igniters, filters, check pressures, CO, draft, and verify burner head settings.

 

Has the coupling between the motor and the fuel pump been checked?

 

Could probably be found on the 'net for about $75 less...

 

Does the tesco burner have a coupling? Any idea how to get to it? Pull pump off?

 

All of the above was done except for pressures, co, draft

 

Why was co2 and over fire not done ?

 

Ed, I'm sorry, but I don't know anything about the Tesco burner particulars.

It must have a coupling though.

With Beckett and others, one would typically pull the motor though...

 

Broke down and had an independant oil repair guy come by. I buy my oil cod so no oil company wants to do service which is to bad. He checked it out and told me I had a vibration issue. He replaced the fan and mounted the triple aqua state on rubber and it is running fine. I am apprehensive that this was the problem but it is running nice and has cycle 3-4 times with no sputtering. I will update this thread if anything else needs to be done or if the vibration does not correct the problem.. Total bill was $135 which I think was more than fair for the 1 hour and 15 minutes he spent here plus the fan.
FYI: the tesco burner is a becket AF burner.

 

Everything was running fine until an hour ago.. Now I have to keep hitting the reset button on the Aquastate. It's a Honeywell triple aqua state. Any ideas I push reset button it fires, runs a minute and shuts down.

 

The word is aquastat, one word and no e on the end. Aqua means water and stat is short for thermostat, i.e a thermostat that controls the temperature of water.

 

Thank you for the spelling lesson, autocorrect on the iPad has its own mind. That doesn't give me heat. Lol

 

So does aque - so why isn't in aquestat ? lol

 

If the burner runs with out sputtering after it has been shut down for a 1/2 hour may indicate a clogged oil filter .

 

Let's just say I'm dubious of this diagnosis! It's actually sorta silly.........

Yes, but first post said the filter was changed and the lines blown out.

I've suspected fuel supply issues from the beginning myself.

Ed, where is your fuel tank located? Above or under ground?

Where is the burner in relation to the fuel tank? Above or below the level of the tank?

Is the fuel supply using ONE or TWO pipes?