Weil McLain Ultra Oil

Warmfoot

I have a Weil Mclain Ultra Oil 3-Section Boiler that is located in an unheated detached garage. Supply lines go from the boiler to the house where we have our mechanical piping and Indirect Water Heater.

My problem is....Whenever it get REALLY cold, (in the Seattle Area..30 deg.) the boiler locks out. We have gone out for the past few years (during the winter) had to reset it up, occasionally clean it because it sooted up. When it fires from a cold start, it has a tough time running until it warms up, then it runs great. All the numbers are good/great from out combustion tests.

My question is...has anyone had similiar experiences with this type of problem? The only thing I can think of is the unconditioned garage space. When the ambient air is cold, the boiler does not like it. It is insulated and drywalled, just no heat.

Does anyone have any ideas?

Ernie Bogue

Master Hydronics

Rusty Powers

Tripping Reset

Hi Ernie
I can give a few things to check, as we've put in dozens of UO's. Yes cold air can be a factor, but not much, as my direct vent unit pulls much colder air (in Alaska) w/o any issue. If your flame is lean to begin with, then colder air can do it. Also low oil pump pressure and/or poor oil supply will do it...do you have a tigerloop on it?
Usually we find a high cad cell reading (4 flashes) when there's a nusance resetting problem.
Aligning the lens with the hole in the firing assy is critical. Lastly the Beckett electronic transformers are having issues- but your symptom sounds more like an unstable flame. What is your oil pump running vac and press readings?

Rocky_3

We have found

they do not like to burn cold fuel and air. The Beckett NX burner is very touchy when it comes to cad cell readings due to the "necked-down" blast tube. Visible light from the flame has a hard time getting back to the cad cell. Consequently anything that diminishes the flame (cold air, cold fuel) can often push the cad cell reading over the limit leading to nuisance lock-outs. Beckett has a retro-fit drawer assembly that helps this problem, as well as advising you to install a small piece of kaowool liner down the middle of the firebox: guess it helps reflect more light to cad cell or creates a more stable flame quicker, or both.
Love the boiler, but the you have to know some of its idiosyncracies.
Rock

Warmfoot

Yes, We install Tigerloops on all new oil installations, we have replaced the ignition transformer. I don't have the all the combustion and pump numbers in front of me, but I know that they all were within tolerable specs.

Again, this only seems to happen with the colder weather. We are pulling air from the garage and it is not direct vented.

Ernie

Rusty Powers

Which firing rate?

If it's the low rate, do you have a liner on the bottom of the firebox?