Multizone system hot & cold plenum temperature controls.

[comindustrial]

We have several air handlers with a hot & cold deck multi zone system serving different zones in the building.Each zone is controled by a Honewell T921 propotional thermostat which activates a 24 volt modutrol motor to open & close hot & cold dampers. The plenum temp. is also changed with reference to the return air temp.
At this time Hot ( steam coil) Plenum temperature is controled by a now obsolete Honeywell R7080A controller modulating a M904 modutrol motor ( 6 wire 1,2,3,4,G,Y T) connected to a steam valve ( two sensors sense Return & supply temp). R7080A controller has a pot to set plenum temp.as well as a pot for percentage & authority settings.
What is the replacement controller? Honewell tech support ?
Any suggestions .

 

[imok2]

This might work..Call Honeywell

Excel 50 Controller Highlights


Inputs/Outputs

8 analog inputs (universal), 0 to 10 Vac
4 digital inputs, 24 Vdc
4 analog outputs, 0 to 10 Vac, 1 mA
6 digital outputs, 24 Vac per triac