Hilozer
New Member
We have a hot water boiler system. There is a control box on the wall that contains two different control units. The first is a Tekmar 250 one stage electronic control which has numerous settings, a supply temperature sensor, and an external temperature sensor. One of the settings is a Warm Weather Shut Down (WWSD) which prevents the boiler from running when the outside temperature is above a set limit.
The second control unit is a Johnson Control A19ABC-36. This is a basic temperature controlled switch. The sensor bulb is mounted outside (same location as the Tekmar outside sensor). This unit is wired to cut all AC power to the boiler when the outside temperature reaches a set point.
The Tekmar WWSD feature and the A19 temp switch seem to perform the same basic function: prevent the boiler from running when the outside temperature is too warm. Both units are installed in the same box and seem to be original. It seems that the Tekmar control would be sufficient on its own and the A19 could be eliminated.
Does anyone know why there would be two devices that basically do the same thing?
Thanks in advance.
The second control unit is a Johnson Control A19ABC-36. This is a basic temperature controlled switch. The sensor bulb is mounted outside (same location as the Tekmar outside sensor). This unit is wired to cut all AC power to the boiler when the outside temperature reaches a set point.
The Tekmar WWSD feature and the A19 temp switch seem to perform the same basic function: prevent the boiler from running when the outside temperature is too warm. Both units are installed in the same box and seem to be original. It seems that the Tekmar control would be sufficient on its own and the A19 could be eliminated.
Does anyone know why there would be two devices that basically do the same thing?
Thanks in advance.
