weil mcclain ultra II faults

Anco361 · March 1

We installed this propane fired Ultra II about 15 years ago.

For the first 5 years it worked flawlessly. It heats an apartment, dhw, and radiant in our garage floors.

After the 5th year we would get occasional faults, always resulting in hard lock outs. Regular cleaning, new igniters, and eventually a new gas valve helped its reliability. But still, occasionally it would lock out on E-02. Hit the reset and it will start and run fine.

Recently, in a cold snap, it started locking out multiple times a day and being difficult to reset. Did a service, thoroughly cleaned, new igniter, and discovered condensate pump was lethargic. (Moist at bottom of exchanger) Replaced pump, and it started working reliably again. Thought i was good.

This week, outside temps have been above freezing, and boiler is running less.

Every day this week it has quit once a day on an E02.

Shut off the floor loop and it makes no difference.

Note that this unit has always faulted more during windy weather.

It is driving us crazy as it provides heat to a tenant, and I can't trust it to stay online.

I have had it looked at by licensed techs and they see nothing wrong. Most suggest changing the board to the new style. Others have mentioned that possibly the gas line is undersized. But why did it work perfectly for the first five years ?

I've searched for knowledgeable weil mcclain techs in my area to no avail.

I'm willing to replace, not sure what I would put back. It needs to be direct vent as it is on the garage floor under a staircase.

Any thoughts, advice, etc appreciated. Or a knowledgeable gas boiler tech! (we're in CT)