hydrostat 3250 and my new boiler

EdTheHeaterMan

So there is one wireless thermostat on one zone, and 3 wired thermostats on the other zones. Is there an extra conductor (unused wire) on one of the main floor thermostats or on the bedroom floor thermostat? And what model number thermostat are you using for the wired thermostats?. never mind. RTH7600D1030

TerrS

@EdTheHeaterMan

 Yes,  I ran 3 conductor wire, but not using it for common to the thermostats. I am just using the batteries.

EdTheHeaterMan

Good, you will need it for the W2 wire on the thermostat you are going to use for the relay.

EdTheHeaterMan

When I looked at your thermostat instructions, it appears that you may have a W2 terminal on the thermostat you already have. If that terminal is usable, then all you need is the relay.

Please verify that you have RTH7600D1030
Last 4 numbers will let me know if it will work.

EdTheHeaterMan

This is your wiring diagram with your existing thermostat (with zone 4 selected as the recover relay zone) I have added it as a file below so you can zoom in.. Print this and leave it near your boiler for reference.
Once you have this wired, You can go to advanced settings on your thermostat and use these settings

Let me know how this turns out for you!
Sent a PM with phone number in case you need answers in real time. Text me and I will call you back.

TerrS

@EdTheHeaterMan

 So I miss-spoke about my hydrostat model number, as I was looking to match up your picture. What I did was mirror MikeA post and his issues matched my perfectly, so I started this post to see if there was a work around for making the boiler come up to temperature quicker, before you offer a possible bypass. So I have to truly apologize.

My new boiler has a 4200 internal hydrostat. So my zc and zr are pinned out and, I think run to my zone control board. But now I am above my knowledge.

I did post 2 pictures of the schematic and 4200.

My last question is what did your solution actually do? Act like a second stage but how does that over-ride what the hydrostat setpoint is?

EdTheHeaterMan

Will look at this. you will have the updated diagram tomorrow

109A_5

Hello @TerrS,
Is it turned on ?


Or is it too bad the thermostat apparently does not work as advertised. Maybe why it was discontinued.
https://www.honeywellstore.com/store/products/7-day-programmable-touch-screen-thermostat-rth7600d.htm

109A_5

Hello @TerrS,

EdTheHeaterMan

Here is the latest diagram based on the 4200a control:



1. The concept is to fool the HydroStat control to get a higher boiler temperature during setback recovery. (at 6:00AM and 3:00PM)
2. The HydroStat will provide a higher boiler temperature if there is a call for DHW. (so we will use that feature at 6:00AM and 3:00PM)
3. The thermostat you have has the capability for 2 stage heat operation.
4. Your thermostat will automatically select stage 2 operation whenever the set-point (the desired temperature) is more than 1° higher than the room temperature.
5. This happens whenever there is a change from set back to normal set point (desired temperature). For example changing from 64° to 68° is more than 1° higher
6. By operating a RIB relay with stage 2 from one of the thermostats, the relay contacts can tell the boiler to make DHW with higher temperature water. (but we will operate the CH circulator pump)
7. Once the room temperature reaches 67° the stage 2 relay will drop out and the boiler will automatically revert to ODR mode.
8. You must program your 4200a to accept the stage 2 as DHW demand for this to work. (it should come that way from the factory)
9. You must connect the DHW/Zone 2 circulator wire to your existing circulator with a jumper or wire nut at the 4200a control (see triangle note 5)

TerrS

@EdTheHeaterMan

Thank You Ed!!!! for the information sorry for the delayed response the holidays got busy.

So I like this solution, however because of that 40v transformer it is a limitation without replacing it to the 50v like you possibly suggested I have more than 1 zone that has this issue.

So I will tell you without the ODR attached except for the warm weather shutdown mode, my house heats back up those 4 degrees in 1 hour again now. There are still days I see the boiler temp at only 165 degrees but in only 30 minutes If needed it will raise to the 185 and my house is warm again in a lot less time than with that 30 minute thermal boost delay.

It also seems my used gas CFM's are now around 2-3 per day , instead of 3-4 per day with the ODR

So unless something else changes, I am going to leave as it is.

Again thank you for all your help.

@109A_5

 The thermostats work as advertised with no issues, I started with that smart technology on but turned it off. Mostly because I built into my set times how fast my house warms up. So I didn't need the boiler firing to be warm before the time specified. Yes I could have adjusted my times but I asked why change with something that always worked assuming my boiler was at the proper temperature quicker. 

Again thanks everyone for the help and suggestions

EdTheHeaterMan

GENIUS @EdTheHeaterMan !

Thank you, I know.
And I am modest too!


ZC and ZR contacts are 120V contacts that allow a second zone control like the Honeywell R845A or the Taco SR501 to operate properly on a tankless coil oil burner system. ZR will take power from the accessory (second zone) switching relay and turn the oil burner (or 120VAC gas valve) with the high limit in the circuit. This will allow the burner to stay ahead of the boiler temperature when the second zone calls for heat.

If the second zone is too large and dumps a lot of cold water back into the boiler You could end up taking a cold shower. To prevent that, ZC powers the second zone control. If the boiler water temperature drops below the low limit, the second zone looses power and the circulator pump for the second zone stops. This allows the burner time to catch up, giving the boiler temperature DHW priority.

That is what the ZC and the ZR were initially intended for. With the HydroStat, and other electronic controls, they will operate the same way. But there is an added feature in these electronic controls for use with indirect tank systems. By connecting the ZC and the ZR together, you basically offer the indirect Priority over the space heating systems. In the case of the system using the ODR with the lower boiler temperature, a DHW call would not recover very fast, so to get the higher boiler temperature, you place a jumper from ZC to ZR to make the boiler operate at the high limit setting in order to have a faster DHW recovery, and drop back to ODR operation when the call for heat is finished.

In the case of @TerrS above, I used the idea to fool the control to make the hotter water for the setback recovery by using the DHW priority feature on stage 2 of a 2 stage thermostat.

I believe I have already posted the diagram you would use in error because @TerrS indicated she had your control and not the one she actually had. So that diagram is already there. The fact that you only have one zone does not change the logic. But if you only have one zone and you do not have a second zone control of any type means that you may need to get one, (Like the TACO SR501) in order to use the C wire on the switching relay to power the RIB Relay for stage two the make the ZC and ZR connection. You can't just use the low voltage stage 2 wire on the line voltage terminals.

I would need a list of all the controls you have in order to may your diagram.
Thermostat model number
Switching relay if you have one
HydroStat model number
Is there a separate LWCO or are you using the built in one on the HydroStat?
Any other 24 VAC transformers that you are currently using in order to operate a smart thermostat
Any other relays that you are currently using in order to operate a smart thermostat
What primary control you are using (if it is oil heat)
What brand tools do you use for you work on heating equipment?
and finally, What make and model vehicle you are using as your daily drive?

The vehicle and tool think is a joke

EdTheHeaterMan

Not knowing your thermostat, here is one way to do it, It my not be the best because the transformer in the one zone relay may not be very powerful to power both the relay itself, the RIB and the Smart Thermostat. It will do the relay itself and the thermostat. or the relay itself and the RIB. I would be a little cautious about doing all three.

EdTheHeaterMan

EDIT: I think I answered my own question. ZR ZC are 120v AC. Regardless of the current, I probably wouldn't want to be connecting 120v directly to any thermostat, right @EdTheHeaterMan ?

Correct

EdTheHeaterMan

We should use your existing discussion, or start a new one.

EdTheHeaterMan

MikeAmann said:

@EdTheHeaterMan
Agreed, but not necessary. I know what I need to do now.
I just thought this would add info to what TerrS already witnessed and described about the way the Hydrostat operates.
But, whether a 2-stage thermostat or timer to fool the Hydrostat for a shorter setback recovery time, the Hydrostat itself is limited to 45 minutes:

• Smart DHW Priority: During a call from an indirect water heater, the control will de-energize the circulator contacts (C1/C2) to heat only the indirect tank ensuring an adequate supply of domestic hot water. The control will re-energize the circulator when the indirect tank is satisfied or if the boiler temperature reaches 170°F. If the indirect call continues for 45 minutes, the control will override the priority function energizing the circulator to provide space heating.

Agree with you on the 45 minute max for the override temperature. and the fact that I show that both the CH circulator and the DHW circulator hot wires from the control are wired to the same circulator provide the necessary operation for her situation. Also the idea of using the higher temperature for the recovery from setback is supposed to make the recovery happen faster then the 2 hour window that it has now. I believe 45 minutes should be sufficient in her case.

In your situation you need the CH circulator to operate when the call for heat comes from the stage 1 or the stage 2 call for heat, even when you are using the ZC and ZR to fool the Hydrsstat control to the higher temperature. You also need the DHW feature to work because you have the indirect for your DHW. So your situation presents a different problem. Which ZC > ZR jump is for hot water and which one is for stage two. That will present a different set of rules and logic to get there.

Are you still interested in the 2 stage thermostat idea? IF YES the we should go to another discussion... IF NO, then we are able to leave it as is. Let me know.