Originally Posted by crocus
The OP said he is getting water out of all of his faucets, so the hot water tank is obviously filling. The relief valve may be plugged?
I thought about this too. If the outside or inside shower faucets were both open and the shower handle was shut off; cold water would enter the hot water pipes allowing both faucets to show water pressure without having the tank filled. (valve in the correct non-bypass position)
If the pressure relief valve was plugged, as the only malfunction, hot water would still flow out the faucets; just not out the relief valve.
So, no hot water; cold water under pressure at the hot water tap; and no water/air at the relief valve is quite the conundrum.
I would be cracking the "B" nut just prior to the bypass valve to make sure there was water there. Replacing the valve may do the trick. I think a clogged bypass valve might be the problem.
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