Weil McLain ultra series 4

beercancold603

Have a Weil McLain ultra 105 installed on site. Boiler goes into soft lock out (return>supply) when outdoor air temp seems to be below 30 and it calls for a zone that has not been running in a little while. Talked with tech support and they said it will happen and would have to happen 22 times for it to hard lock out. Any one else experience issues with this? Also i dont understand if that is 22 time one call or when it racks up the soft lockout 22 times in the count. Boiler was installed using their header kit and has 2 zones for baseboard tied into a taco pump controller. When i see this happen almost looks like the me the boiler during prepurge is bringing in too much outside air for too long and cooling supply down as this is in alarm before the boiler even ignites. I have lengthened the prepurge to 2 mins as a max and this made it worse so i put it back to 45 sec.

109A_5

Hello beercancold603,

Were the items in this chart verified ? Were the sensor resistances verified ?

Item 10 are the sensors.

beercancold603

yes i have confirmed all above is good. The system sensors would have to be seeing the return higher for 10 min for it to go into alarm which while watching it they do not. Its always the boiler temp sensors.

109A_5

Does it do it often enough where you can monitor this display to maybe see some odd behavior ?

Is P14 seated correctly and screws secure ? Have you wiggled or tapped in this area to see is it stimulates anything ?

beercancold603

yes i have looked at screen while the error occurs also this is the last 3 saved fault temps all wire connections have been checked and are tight. now occurring once a day mostly in am when it is coldest outside.

system supply:93

system return:108

boiler out 1:86

boiler out 2:87

boiler in:97

flue 1:118

flue2:117

outdoor:33

system supply:92

system return:105

boiler out 1:85

boiler out 2:85

boiler in:95

flue 1:118

flue2:118

outdoor:31

system supply:90

system return:104

boiler out 1:82

boiler out 2:83

boiler in:93

flue 1:113

flue2:113

outdoor:35

109A_5

Initially, it looks to me like the sensors (system supply, system return or the wires 1, 3) are reversed. The colder it gets out the greater the heat load on the system the greater the temperature differential between sensors. Or the system circulator is flowing the water in the wrong direction.

Looking at the manual and your numbers some more

Is your boiler circulator circulating the water in the wrong direction or are the boiler pipes connected backwards ?

All these seem odd, they all seem backwards.

system supply: 90

system return: 104 - Should be lower than the supply.

boiler out 1: 82

boiler out 2: 83

boiler in: 93 - Should be lower than the out 1 and out 2.