Controls: circulators, mix valves, and actuators

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Maine Way

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Hello All,

The system I am installing has three temperature space heating requirements plus DHW priority zone. Of these temperature requirements, there are multiple zones in each.

My plan is to use manifolds with 4-wire actuators tied to thermostats. Additionally, the thermostat signal needs to go to a controller to call for heat and run associated circulator and mixing valve.

Lochinvar offers an (expensive) controller that does three temperature zones. I have included some information in the uploads.

I have also included my schematic.

1. Is it a sound plan to divide the zone manifolds by temperature, include one circulator and zone valve per zone, and have the individual actuators in the manifold open the zones that are calling by thermostat? It seems expensive enough with the three mixing valves and the three zone circulators and the three manifolds, and perhaps it is over designed? At least I won't need to buy a separate taco controller for this setup.

2. One specific question I have is if the signal from the thermostat is able to be split the signal to go to actuator valves and to signal the Lochinvar controller?

3. Regarding thermostats, I would not require a floor sensor for the radiant with this arrangement, because the supply temp is already limited?

4. Also, the boiler itself has an outside sensor. The boiler will attempt to predict supply temperature already for the cast iron baseboard, maintaining a condensing temp to maximize efficiency. Should I even use a mixing valve (to dictate a specific supply temp) for this group of zones?

Shawn
 

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John Gayewski

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I can tell you what I normally see. The floor sensor is to protect your flooring in the event of a failure (which will happen with a mixing valve).

With relays you can do about anything including splitting a signal and having it control two different things.

Normally hydronic systems don't have that many thermostats, but that is normally due to cost and complexity, but also the emitters on each room should be sized to heat the room. So as long as we know that it's getting hot water it's giving the correct amount of heat. Micro controlling isn't usually something that people find they need, and if so it's added.

Constant or near constant circulation with Trv's goes a long way toward simplifying things.

This is the beauty of hydronics. You can dive into the weeds and stay there for a lifetime. Tweeking and recording and learning.
 
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Maine Way

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Hello fitter30,

My plan is to have 3 temperatures plus DHW.

I am using cast iron baseboard as a high temperature heat (although I would still like to have return water below 130). I am also using an in-floor radiant heat. In this case the tubing is under cement board and tile. Lastly, I am using in-slab radiant in the basement. I was thinking that this application may take a lower temperature than the radiant on the upper floors.

The schematic I have attached to this thread shows these groupings.

I am still unsure about the system setup. I wonder if the Lochinvar controller is overkill. Maybe one thermostatic mixing valve is enough for all the radiant heat zones, and the boiler will provide the right temp to the CI baseboard? Then, a taco controller can work the pumps and zone valves...

Also confusing to me: if I decide to go with the Lochinvar controller, which mixing valves do I need? If I am buying a mixing valves with an actuators for the Lochinvar controller, then would not the mixing valves already be capable of reading temperature and sending the right temperature water into the zone anyway? Why buy an expensive controller?

Shawn
 

Maine Way

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Hello John,

I have ended up with more zones than I wanted, due to a couple reasons. I have mixed radiation types that require different temperatures. And, I am safeguarding for the house to be split into two apartments in 10 years or so. If that does happen, the bedrooms in one wing need separate control. There are two bedroom/bathroom groups I could put on the same zone. And I still may do that. Our current plan for one of those rooms is a guest room that will only be occupied occasionally, so we thought it would be useful to keep the heat in that room lower.

I do think the system has evolved into something complicated. And I am struggling to figure out what I actually need to control it.

I very much appreciate the comment on the floor sensor. I will maintain this in the system. So much for simplifying... :p

Shawn
 

Fitter30

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Maine Way

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Hello fitter30,

Those controls are a better deal than the Lochinvar controller. I thought the Lochinvar would play better with the boiler of the same brand. But, I think it is not needed.

The piping diagram I am considering is the same one uploaded to the original post (boiler scheme 6). But, I think if I can use only one temp for the radiant, then maybe I will modify it to include only one temp from the boiler (for CI baseboard) and one from a mixing valve to achieve the radiant floor temp. The boiler should be able to regulate the high heat zone for maximum efficiency.

I can group these zones by temperature, use one circulator for each temperature, and use actuator valves to turn off and on zones based on thermostat call. Am I making sense or just confused?

Thank you,

Shawn
 
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