Hot Water Generator taking heat from my Hot Water Tank?
I live in Ontario Canada. (hopefully that's a good start to my thread HA HA)
I researched on this forum about HWG (hot water generators) and the proper plumbing into a single electric hot water tank.
I purchased a 10 year old home with a 2005 model Climate Master GSV 060 (5 ton) geothermal unit with HWG. I have owned the home for 2 months and noticed a SUBSTANTIAL amount of electricity consumption. Last month (30 days) 3528 Kw/h. Yep, in Ontario Canada $0.21 per Kw (tax included) equates to $740.00 for the 30 day period. Yeah WOW.
So, we have no gas what so ever in our area. Geothermal Closed Loop system. Yesterday I conducted an experiment to shut down my hot water tank for 6 hours. It is a 80 Gallon REHEEM unit. I have no bunker (secondary tank). My energy consumption dropped in 1/2 for this period compared to the last 60 days. Here is my concern, I think my HWG is plumbed incorrectly to the HWT. I wanted to enter a picture but cannot figure out how so I will try to explain it. Two lines run from the HWG. (in / out). These two orange lines run into a four way T on the bottom of the tank. One is a drain, the other goes into the tank. Does this not create a vacuum drawing the pre-heated hot water from the tank back into the HWG of the geothermal unit?
Another little note: on the hot output (on top of the tank) is a circulation pump which circulates the hot water throughout the large home to acquire on demand hot water at the faucets. It's 1/25 HP less than 25W.
Any specialists that can help me on this would be VERY appreciated. I was told I cannot just close the valves on the bottom of the tank because the HWG pump needs constant circulation. Although, could I just disable the HWG pump and then turn off the valves if in fact this is why all my energy is being drawn from the Hot Water Tank?
First off, if the HWG in/out lines go to two of the 4 ports on a 4-way cross at the bottom of the tank it would just be a short circuit and very little would be done to help your domestic hot water. Doesn't go through the tank at all. If that domestic circulation pump is plumbed in down at that 4-way I would need to see a diagram and I could be barking up the wrong tree. I also don't like a HWG without a "bunker" tank. The electric elements are going to hold the temperature and you gain very little to nothing unless you have a HW demand while the geo is running. And that requires them to be plumbed in correctly!
Originally Posted by parabrush
The inlet to your HWG should be plumbed to a Tee at the cold inlet to your domestic HW tank. ClimateMaster wants the outlet to go into a Tee installed at the tank drain fitting. Since we have always installed our geothermal systems with a non-electrified water heater (bunker) ahead of the electric water heater, instead of the Tee at the drain fitting (hate the tripper it makes) I remove the lower element and return the output of the HWG into that opening. Drain runs cold even with the geo system operating but it looks a bit odd to the uninitiated with a hole cut into the bottom element cover and a pipe going in.
To me, HWGs don't make much sense when the system is running for heating. They make the most sense in AC. You better have a really hefty ground loop with a lot of capacity designed for both space and domestic water heating. Around here the HWG isn't often taken into account when designing the ground loop.
Hope that helps.
these aforementioned 4-way T's for recirc in HW tank drain ports, - in one port have fowled in nearly every one of seen installed since the 1980's.
The PEX tube installers' flood-baths in folks homes are less pretty than where plugged at the 4-way.
PEX has not held up to the convected HW able to hit 170f RARELY when a circ pump is off and a GHP desuperheater is below a cold fluid in a tank, forcing slow , sometimes over-heated pressurized hot water to pop-off the PEX at the inlet to the GHP ( reversed heat migration, likely during restricted air flow/ blower-failing to wipe off heat/ etc).
@ Hawkeyehvac Just curious based on my solar hot water experience why you wouldn't draw cold water from the bottom of the water heater, heat it in the desuperheater and then return it to the top of the tank where the warm water is? Stratification is your friend.