Boiler Storage Tank Immersion Thermostat Control


We recently purchased a vacation home that has an oil fired boiler with adjacent non-powered water storage tank that has an immersion thermostat on it to control calling the boiler for heat. I’m trying to determine what I could do to set things up so that I can leave the water at 60 degrees F (15C) when we are not at the vacation home and bring up to 125F when we are there.

The current thermostat is a TPI immersion thermostat which does not support any sort of automation. There are 6 wires coming into it. 2 for calling for heat from the boiler, 2 for 24VDC and ground, and 2 for the temperature probe. I’ve googled for hours trying to figure out what options I have and finding it very confusing what I can and cannot do. I’m located in the US. I see lots of thermostats, which seem not related to water/immersion. I found something called the Tesla T-Smart, but that seems to be in the UK only. I’ve seen that some regular thermostats also have support for hot water, but I can’t tell if that’s a solution.

Any stories or suggestions would be most appreciated.

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Those only work for immersion heaters which are already designed to work with a wall thermostat, so not suitable for your case.

As to the general question, in the US, like working with gas lines, work with immersion heaters is generally not considered a DIY project. There are too many different ways to cause serious harm, including just very hot water coming out of the faucet when you don’t expect it.

There are also a lot of electrical regulations in most jurisdictions, such as the heater may be required to be on a separate circuit.

Anyway, because it’s not a DIY project, there just isn’t a market for these devices that would fit a typical smartthings budget.

If you contact a local plumbing contractor who does inversion heaters they may be able to offer you a model with Wi-Fi/app control and there might be some potential integration that way.

Hmm, ok, wasn’t quite the answer I was hoping for. I expected people must be using something to manage this with home automation. It seems like immersion thermostats have safety features in them to prevent the scalding water scenario and looking at the Tesla T-Smart site and their videos showing how to easily replace a tank’s thermostat that it was a low to medium level difficulty in swapping out but maybe there’s something more uniform in UK heaters that makes it easier to do.

My scenario has my tank as just a storage tank so there is no circuit for the tank itself, just the boiler. I already did a DIY replacement/C-wire install for a room thermostat so I figured the level of effort was similar.

I sent an email to my boiler maintainance company to see if they have any product suggestions. Going to keep looking for something DIY though.

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@JDRoberts, @morganm00 - I think there is a confusion here.

@morganm00 is really looking for a new immersion thermostat (remote controllable) and not an immersion heater, but has found an immersion heater Tesla T-Smart instead. So there is no separate circuit for the tank, as it is not heated from an immersion heater, but from the oil boiler.

Anyhow, @JDRoberts is absolutely right, as replacing any immersion pieces on a tank is definitely a plumbing job and should be done by a professional. Just imagine when somehow it would fitted incorrectly and the hot water when pressurised starts to spray… The video is misleading as the guy does the job on an empty and brand new tank.
But I am guessing here that you have a really immersed sensor. Many storage tanks has a pipe in the middle which has an opening on the side and the sensor just placed inside this pipe and it is completely a dry solution. The sensor just placed inside this pipe from the hole on the side and the sensor has only contact with the wall of this pipe and not the water inside the tank. In that case the replacement is not complicated as you can just pull out the sensor and replace it all together with the thermostat.

But really my advice would be to talk with a professional who has a better understanding what controller you really need. It is more of an issue for failsafe events. Especially when the weather is below 0 Celsius.