Heating cedar hot-tub with combi boiler. Need thermostat suggestions

[dave_w]

I am Looking for a reliable programmable 24v Wi-Fi enabled thermostat with external probe control for Navien combi boiler for boiler zone control. Zone is used with a stainless Bowman heat exchanger for a cedar hot tub and I want the zone to maintain hot tub temp for 3 different events - away (50-60 deg), standby (80 deg) and active (102 deg). Hot tub side is a black and decker VS pump controlled by 5v relays.

This one looks promising but isn’t readily available in US.

MCD5

“All-in-one” clock thermostat for electric underfloor heating creates optimal comfort temperature and the lowest possible energy consumption.

ojelectronics.com

Any other suggestions??

I am also still trying to work out coordination between the VS pump side controlsrelays and the Navien control board Open to ideas if anybody has tackled this. Though I don’t mind having to control each independently and it seems no harm if one side is on without the other



Thanks in advance.

 

[ajw22]

Welcome to TFP.

Below is a thread where @xrabbi discusses using a Heat Exchanger on a pool…

How to Properly Run Plumbing Through Heat Exchanger?

Our PB completed the plumbing setup before the inline heat exchanger was available for installation. Now that we're installing, I'm not quite sure the plumbing is set up quite right. Would really appreciate any advise/observations on the setup and how it really should be arranged. As you can...

www.troublefreepool.com

I have not seen anyone do the type of controls you describe. Let’s see if any steps forward with ideas.

 

[phonedave]

I cannot seem to find something that meets all of your needs.

Reptile temperature controls fit all of the criteria (Wifi, 24V, wet sensor) except temp range (nobody wants their lizard at 102F)

Granger makes a bunch of controls, but without WiFi

Your best bet may be a Nest Thermostat. It is 24V, WiFi, programmable. and supports remote sensors that go from 32 to 104 F operating temp. The only issue is the remote sensors are air sensors. Not sure how they are designed and if maybe they can be potted and made into a water temp sensor. Or maybe somebody makes a water sensor for it.

 

[dave_w]

Thanks. I have a spare ecobee but they will not accommodate an external hard wired temp sensor. Some radiant floor heating systems use external slab sensors and give the option to drive from just that sensor, ambient room temp or average bott. But most run on line level voltage and the few I found that were 24v had terrible reliability reviews. I would think the hydronic floor industry would have some solid ones by now.

 

[phonedave]

Thanks. I have a spare ecobee but they will not accommodate an external hard wired temp sensor. Some radiant floor heating systems use external slab sensors and give the option to drive from just that sensor, ambient room temp or average bott. But most run on line level voltage and the few I found that were 24v had terrible reliability reviews. I would think the hydronic floor industry would have some solid ones by now.

Again, I can't seem to hit all of your requiremetns

Here is a a line voltage solution

APOLLO Wi-Fi Pool Aquastat

Simply the best Wi-Fi Pool Aquastat on the market. Designed in the USA. Main Feature Pool or Spa precise temperature control 35ft sensor included 2 stainless clamps for 1.5" and 2" PVC. 110 to 240V input voltage Universal voltage control side with COM and NO / NC relay. 3.5” High-resolution...

www.mbtek.com