Hot water troubles

We just moved into an old farm house.

It has an electric tank which is supplemented by our wood boiler during the cold months.

The issue: Hot water cools rapidly to luke warm. Has been like this since we moved in. Starts blazing hot and cools down almost instantly. It is as if the cold water supply is mixing in at the hot.

Cold runs in at the bottom of the tank, so there is no dip tube.

There is what appears to me, to be a bypass connecting the hot and cold directly above the tank. Is this normal? I feel like if I disabled (removed) the bypass pipe, it would solve my problem.

Would I be correct in doing so? And if so, why was it installed this way in the first place?

If I am incorrect, and this is a perfectly normal configuration, do you have any suggestions for which could help me solve this dilemma.


-fraser

Here is the actual image:View attachment ImageUploadedByPlumbing Forum1424960809.936013.jpg

The pipe on the left is the cold supply, it continues down to a bottom inlet. as you can see it is directly connected to our hot water just above the hot outlet.

I have now located a three way brass coupling that I assume is intended to mix (it's labeled hot, cold, mix).

Can anyone tell me what this is for/is it adjustable/what would happen if I removed it outright?

View attachment ImageUploadedByPlumbing Forum1424961478.279340.jpg

I'm thinking that by the looks of all that cal/lime crust spewing out of the valve, it might not be functioning properly. I'm just going to go ahead and remove it entirely.

I think I know the answers to my own questions, but any opinion would still be a help.

I figure the mix valve is there because the wood boiler has the potential to get the tank temp dangerously hot. I'm going to replace the valve with a new one instead of removing it entirely.

I would definitely want a tempering valve in there, if there is any potential of the boiler overheating the water in the tank.

Off of the top of my head, I am not sure the ASME rating number that you should use for that application, but I am pretty sure what is there now isn't right.

Yeah turns out the water in our tank was registering at almost 150 the other day when the the boiler was going!

Replaced the old mixing valve with this Apollo MVA--BS12. Now running at a constant 120 when valve is cranked. View attachment ImageUploadedByPlumbing Forum1425158248.409975.jpg