Weil Mclain Ultra 310 gas valve fault 1

[bob_scheel]

A customer asked me to look at a boiler installation they had that was done by another contractor. It is now out of warranty with that contractor. They have had a lot of problems with lockouts.

I checked the installation and found that none of the 4 boilers had been set up properly. Gas pressures were too low, CO2 was outside specs, etc. Got everything tuned up properly and the problems went away we thought. Tune up was done in August before hardly a week went by that they didn't have a lockout before that. Gas pressures were checked and set with all 4 boilers firiing at 100%.

Just this past weekend we had two boilers lockout on gas valve faults and the history log status says boilers were in post purge. All 4 boilers also lost their time of day, date clock data about a week before that too.

Then Friday a third different boiler locked out on gas valve fault. I am suspecting gas pressure problems as I think it unlikely that 3 different 1 yr old boilers would have gas valve problems. However I know that there were some recalls on controls for these boilers. I changed out 2 controllerer in August because they were on the recall list.

Has Weil Mclain solved their control problems with these boilers?

[hedtedjr]

Haven't dealt with the ultra's a ton. Sounds to me though like maybe its an incoming power issue. One of our accounts has had so much problem with their power frying things that they installed giant capacitors to filter the incoming juice and smooth out the peaks and valleys. Found similar issues, though not as extreme in many places that have high draw equipment on an older power grid.

[guy597]

Is this a erratic problem ?

[bob_scheel]

Is this a erratic problem ?

Seems to happen mostly on nights and weekends, not during the weekday. Just tried an experiment adding some time delays to the start/stop signal. The system has 3 sets of pumps/loops. Each boiler has one, then there is one to a plate heat exchanger for all 4 boilers, then there is the main bldg loop. The guys that installed didn't integrate it with the bldg. EMS, they just replaced a steam heat exchanger with the water to water plate exchanger. The EMS has a 0-10v signal for the old steam valve which they didn't use. The EMS also starts/stops the main bldg pump on outdoor air temp and on demand when unoccupied.

We think that when the heating demand from a single floor is triggered by a drop below 55 degrees that the pump starts, the boilers begin to fire, eventually firing several, and then the pump shuts down, essentially removing the load suddenly. We added a relay to delay the shutdown of the main pump for 5 minutes after the EMS shuts down the boilers. (Didn't have separate control before.)

Ideally I would like to control the boilers modulation rate with the 0-10v signal. The way it is setup now each of the 4 boilers tries to hold its own loop at 180 degrees and a pump controller stages the boilers up and down by time.