HVAC Site - Professional HVAC Contractors Forum banner
1 - 7 of 7 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hi all, I'm looking at a condo unit with a heat pipe system and two fan units in separate rooms (Enviro-tech Enviro-Pack Model VHC Size 06, FC6-14-4., The Valves are Erie Controls). Currently connected to TAC T155-010 (120v) Thermostat, vertically mounted on a standard 2x4 electrical box.

They'd like to replace the stats on both units with a more modern stat digital stat that will allow for better temperature control and auto controls for the blower / toggle between heating and cooling.

I've dug up the instructions for the TAC T155-010

Currently wired to the stat is:
Terminal block 3:
1. Heat
2. Cool
3. Sw'd Power

Terminal block 2:
1. L1
2. High Fan
3. Med Fan
4. Low Fan
5. Fan Hot

Terminal Block 1:
1. L2 (Neutral)
2. None Connected
3. None Connected
4. None Connected

The closest replacement I've been able to find is a Honeywell TB6575, adding the adapter plate. It would appear though I have two extra wires - Fan Hot and Sw'd Power.

For the Honeywell Model it's wiring is:
L (hot)
Heat Valve
Cool Valve
Fan Low
Fan Medium
Fan High
Neutral
Optional - remote sensor
Optional - remote sensor
Optional - Setback
Optional - pipe sensor

Can anyone give me some advice on this. Help with the wiring or alternate new stat for this upgrade?
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #2 ·
I forgot to say, fan hot and switched power are jumpered together in the cable harness.

This unit runs all the time on low unless set to off.

The goal of the new stat is to shut the fan off when the temperature is reached.

Not sure if the replacement stat has the relays to shut off the fan when the temp is reached and the valves are closed.

Seems like the current stat could switch the blower off if it had the 110v relays added for the hot and cold valves.
 

·
Registered
Joined
·
3 Posts
Discussion Starter · #3 ·
My other stat option that i know is is a psg nepra iii (120u2f). It limits the fan to high and low, but the documentation indicates it has a auto mode that will shutoff the fan as desired.

I guess I need to call honeywell in the morning.
 
1 - 7 of 7 Posts
Top