[JDForinger]

I am trying to wire an 8-wire White-Rodgers Big Blue (model 1F95-1277) thermostat to accomodate 1 cooling stage and three heat stages. I want my Hydronic Water heat pump to be the first stage heat, the Hydronic Forced Air to be the second stage heat and the electric heat strips to be the third (or emergency) stage heat. The thermostat wires go to the Hydronic Forced Air unit, which has a 4-wire interface with the Hydronic Water heatpump. The confusion factor is mostly around the thermostat wires connected to the following terminal designators:

Y1 - I want the Hydronic Forced Air to be a single stage cool, but second stage heat, so I don't know how to get the signal to the Hydronic Water unit.

Y2 - I think the thermostat Y2 should be connected to the Hydronic Forced Air 2nd stage heat connection

O - Seems like it is obvious and should be the Hydronic Forced Air reversing valve call at terminal O

B - Should this go through the Hydronic Forced Air interface wires to the Hydronic Water reversing valve terminal O?

W2-W/E - Should they be jumpered, or separate. If separate, I think that the W2 should go to the Hydronic Forced Air teminal W, and the W/E should go through the hydronic forced air interface wires to the Hydronic Water terminal W1. If jumpered, do I just connect the one thermostat W2-W/E to both the Hydronic Forced Air terminal W and the Hydronic Water terminal W1?

If it matters, my Waterfurnace Hydronic Forced Air Heatpump is an Envision 208-230/60/1 and my Waterfurnace Hydronic Water Heatpump is an E-Series EW042 model.

Thanks to anyone who can help me decipher this. I installed it myself two years ago, but this is the first year that I got the radiant floor heating ready for the mainfloor because until now the forced air was heating the mainfloor and the radiant floor was only heating the basement slab.

 

[beenthere]

You'll need either 2 thermostats to do what you want. or, you'll have to add relays and temp sensors to get it to work automatically summer and winter.

 

[JDForinger]

Well I actually have 2 Big Blue thermostats, but only one wired in. The design was such that I would have two cooling zones (the whole upstairs and the whole downstairs) and four heating zones (2 upstairs and 2 downstairs). The heating zones had two thermostats upstairs, the Big Blue, which controlled radiant floor heating to the common areas, and a heat-only thermostat, which controlled radiant floor heating to the sleeping areas. The basement has two heat-only thermostats for radiant heat in the slab. The other Big Blue was intended for the cooling zone in the basement, but it is overkill and I keep it as a spare. The Big Blue is a 3 stage heat, 2 stage cool capable thermostat for heat pumps. The three heat-only thermostats are wired directly two the radiant floor source manifolds. The four interface wires from the Hydronic Air heat pump to the Hydronic Water heat pump are not presently connected and are intended to get signals to the fourth heat zone for the upstairs common areas. I think that I'm thermostat heavy, just need to decipher the connections. Thanks for replying.

 

[beenthere]

What you need. Is a BAS control for your system.

A 3 stage heat, heat pump thermostat, ALWAYS energizes Y1 first for heating or cooling. So with it connected to the air heat pump. It will always make that first stage.

A BAS can be made to call the water heat pump first.

However. It might be more then you want to pay for. And would be controlled from a central unit or PC.

 

[JDForinger]

Well you made me think of something as a different possibility, applying your first post with relays. Could I hook up two PAM-1 relays in the forced air unit to do the job? The relays would be energized by either B or O from the thermostat for hot or cold. They would share the same Y1 signal to ensure that in heat it would switch to the water unit and in cool it would switch to the air unit.

So, the unanswered question in my mind is: Would the air unit, in heat mode, turn on with a Y2 call if it didn't have a Y1 call, and if not, maybe a third PAM-1 could be configured to make both units receive the Y1 in that instance.

Thanks for helping!

 

[beenthere]

You can use ther relays to control which units gets what call as you described. And using the O for cooling calls, and B for heating calls can be used to energize the correct unit.

Some control boards must have a Y1 call for a Y2 signal to be recognized. You'll have to check the manual for your units to see if they do.

 

[JDForinger]

Thank you so much. This is good news. Being and old Navy electronics tech, designing relay networks doesn't scare me too much.

One last theory of operation question: When a thermostat progresses through the heat stages, does it keep the earlier stages still hot? In other words, does Y1 stay hot from the t-stat, when Y2 is active; and, do both Y1 and Y2 stay hot when Emergency Heat is hot?

If the answer is yes, then I won't need an additional relay for the 3rd stage Emergency heat.

Thanks again.
Best regards,
JD

 

[beenthere]

Y1 is energized the whole time Y2 is energized.

Emergency heat, only it and the fan in some cases is energized. Y1 and Y2 are de-energized. Or it would just be aux heat( a third stage), instead of emergency heat.

However. Y1, Y2, and W2(designation varies with the thermostat) can all be energized at the same time.

 

[JDForinger]

Success

Thanks for your help. It took this long to design, test, go back to the drawing board two times, etc., but it is running as I intended. It took a total of eight PAM-1 relays; six in the water-to-air unit and two in the water-to-water unit. It is successfully cycling through OFF/COOL, HEAT Stage 1 (water-to-water only), HEAT Stage 2 (stage 1 plus air-to-air), HEAT Stage 3 (stages 1 & 2 and auxilliary resistance strips), and EMERGENCY Mode. Thanks again!
Best,
JD