Water Heaters and Geothermal Heating
CherBear2022
| Posted in General Questions on
Hi there,
We recently purchased a home in the country which has existing Geothermal heating. No gas line to the house at all. The existing hot water heaters are 17 years old and need to be replaced. They have hoses coming out of the bottom sides of them that I am not familiar with. Do I need to buy special hot water heaters to work in conjunction with the geothermal heating system in place?
Thanks in advance!
Cheryl
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Replies
It sounds like there are multiple tanks correct? Often geothermal uses a preheat tank and another finishing tank. The preheat tank uses a pump to circulate water from the bottom to the geothermal's desuperheater and back into the top of the preheat tank, which often has no heat source of its own (or a deenergized heat source). The pump is often within the geothermal unit itself. The water then flows from the preheat tank to the finishing tank. If these are regular electric tanks (think Home Depot) then there's nothing special going on. In fact, they might not be connected to the geothermal system at all. However, they could be higher end storage tanks, in which case, besides age, is there another reason to replace them? Their lifespan can be much longer. So no, you don't necessarily need special tanks and you also may not need to replace them at all. If you did replace them, they don't have to be connected to the geothermal system either, although it's more efficient.
Can you draw out/post a picture of what the setup looks like?
Thanks!
Here are some pics...
A heat pump water heater would have a drain hose for condensate attached.
I think you would be better served if you delay replacing the heaters until one of them is leaking/ broken. Generally, they tend to fail slowly in that at first the leak is small and slow giving you time to arrange a replacement. I might feel differently if the leak would be near a wood or carpeted floor that would be damaged. They do sell alarms that would alert you in the event of a leak.
Consider posting a few photos of the labels based on your description we are mostly guessing.
This photo is a heatpump water heater
Walta
thanks! I posted some pics in the above reply so you can check if this is what we are talking about.
It looks to me like for some reason they relocated the Temperature and Pressure Relief Valve (T&P) this is a critical safety device. If you look at the attached picture you will see the sensor for the valve extends into the tank. It seems unlikely the sensor of your valve could be long enough to reach the tank after it was relocated.
Seems to me the pipe that is connected to T&P port could be connected heaters inlet connection and would function in the same way.
It does look like your water heater is connected to the ground source heat pump.
The heater itself is a normal electric water heater.
Walta
It looks like a regular tank with something plumbed into the t&p port at the top and at the drain port at the bottom. That makes me think that water is being sent somewhere else for heating, what you'd do is pull cold water out of the bottom and return hot water at the top. Alternately, it could be that water is being taken out of the tank and used for heating elsewhere. Can you trace where those pipes go?
Is anyone else shocked by how the code required safety device is compromised in this installation?
DC most ground source heat pumps are connected to the domestic hot water as shown in this diagram.
Walta
Don't you think that pipe is going to get as hot as the rest of the tank anyway? And the real danger is pressure, which that is going to vent. If the water heater overheats venting the hot water doesn't really do anything.
But overall the installation does have the look that it was done by someone not a plumber.