Utica Boiler pilot gone out 50x, need Albany NY expert or your suggestions

Albany Chris

I have a Utica MGB boiler whose pilot has gone out 50+ times over the last few years. We have replaced pretty much everything at least once including the pilot assembly, gas valve, & aquastat. We have installed the Johnson Controls K16RA thermocouple. We have cleaned out the pilot gas tube. The HWH on the same gas service works fine, as do the other boiler & HWH on the other service (2-family house).

Does anyone know of someone in the Albany NY area who has the expertise and will take the time to figure out the problem? I do most of the troubleshooting and repairs for the 22 boilers in my rental units and I have had a few guys in to work on this one but once it is running they are done.

Or do you have any other suggestions for me?

I contacted Utica suport and they suggested replacing the pilot assembly (which I did). I have read extensively here on HH about how to set up the thermocouple with 1/3 to half of it in the flame. The pilot flame seems robust when it is working.

EDIT I should add that replacing the pilot assembly seems to have solved most of the problems. It went out in Nov '18 and we replaced the 8 month old thermocouple, it went out again in March of '19 and we replaced the thermocouple with the K16RA, and it is out again today.

Thanks to everyone in the HH commmunity.

Jamie Hall

First thing I'd think of is to check the gas pressure when the unit tries to fire and various other units are already firing. Then check it when it's not firing, but when other units fire up.

Any reasonably competent service technician should be able to do that, and to check all the adjustments...

STEAM DOCTOR

Make sure that boiler heat exchanger and chimney are clear. Make sure that there I'd adequate air.

Tim McElwain

What did you get for millivolt readings on the thermocouples? Did you do a combustion test. How is this unit vented. Some pictures may help. Is there enough air for combustion in the combustion zone? What size is the room in which it is installed and is there other equipment in the room?

Leonard

Don't know your unit but is it possible some ventilation fan is pressurizing or making a vacuum on the house and making a hurricane draft by the pilot?

Or is boiler in a SMALL room and when room door slams the pressure wave blows it out?

Once I saw pilot pressure set too high and flame was lifting off it's tube, unstable flame

Albany Chris

Thanks for everyone's input - some great ideas here. Turns out I may have been premature in panicking - the K16RA thermocouple had a pile of melted crud on it that was likely keeping it from heating up enough. Apparently it comes with some coating or covering that needs to be removed first before installing and I didn't see it in the dim light of the basement (speaking of dim lights...).
I will use some of these ideas if this re-occurs.

AJCimino

In the late eighties and early nineties, I remember Utica having this problem on their PEG steam boilers. The local supply house at the time took quite a lot of flak over the issue. What ultimately happened was that Utica supplied replacement pilot burners. The pilot bracket was mounted at a 45 degree angle with a reduced pilot flame and what was referred to as a "husky" thermocouple. I'm not sure who made the thermocouple, but it was more substantial than the regular one; this fix seemed to work. I never remember this being a problem on the MGB's. However, a few years later this cropped up on the Peerless hot water boilers, and the fix was basically the same. I still have one of the replacement pilot burners from Peerless. I believe that ultimately it was thought that the pilot flame was too strong and caused premature thermocouple failure. Fifty failures would dictate that the problem is more than crud, and I've never seen a thermocouple with a coating on it out of the package. One more thing: when I called Utica years ago, there was a man named Jim Benson (I believe) in engineering who was always very knowledgeable and helpful. I wouldn't know if he's sill there, but you may want to try.

Tim McElwain

@AJCimino The pilots on these systems should have an .018 size orifice and the pilot should have a soft blue flame not roaring or lifting. It should envelope the upper 1/2 to 3/8 of the tip of the thermocouple. The tip should glow "dull red" not "cherry red". A number of boilers from back in the 60's, 70's and earl;y 80's had problems with the pilot being to close to the bottom of the boiler heat exchanger and in extreme weather conditions with constant running it would burn out the thermocouples due to over heating them. Johnson Controls was the manufacturer of the Husky thermocouple especially the K16RA corrosion resistant/high temperature nickel plated version which would solve that problem. Those same thermocouples today are manufactured by BASO Gas Controls LLC which bought out that division of Johnson Controls.

Albany Chris

For anyone who finds this thread looking to fix a similar problem...

We are pretty sure that the problem has been condensation from the boiler sections dripping on the thermocouple during startup with cold radiators. I am going to craft a metal shield and mount it above the thermocouple.

A tech troubleshooting this for me immediately asked if the house had cast iron radiators (yes) and if there was a loop on this boiler that mixed exiting hot water into the return (no) and then diagnosed condensation. ( I always called this a Hartford loop but I guess this term is really used for steam.)

This is very consistent with the seasonality of the problem - the pilot rarely went out in the peak of winter (when the radiators likely never had a chance to really cool down) but was much more prevalent in the shoulder seasons.

Ironman

You need a bypass piped in.

Peter_26

Maybe your are just fixing one problem, but not addressing the main one, which is the condensation. Prolonged condensation will eventually kill your boiler. So, there is no boiler bypass loop and that's your real problem. There are a lot of good threads on here that helped me.

When's the last time your boiler had a good cleaning? What if any issues did the tech find?

Steamhead

Also, if you replace the aquastat relay with a HydroStat or AquaSmart type, the new control can be set to hold the circulator off and let the boiler warm up so it won't condense.