LLigetfa
DIYer, not in the trades
OK, here's the scoop. My water is aerated with a micronizer for iron removal. That is the only point where air is entering the system. Cold water comes up through the floor, into the top of the tank. Hot water comes out the top of the tank and goes back down through the floor. It's been that way since I built the house over 12 years ago. Now, I will 'fess up that I should not have taken the cold supply to the WH off of the side of a Tee, as the straight through wins out every time. (Maybe that is sage advice to others, looking to save their marriage).
When this aerated water is heated in the tank, some of the entrained air is released causing an air lock in the plumbing. When drawing warm water, I always draw just hot at first to purge the cold water (and the air) from the line. When, and only when it runs hot, I mix in cold to achieve the desired temp. Been doing it this way for 12 years.
Enter the wife... she has a large soaker tub... lemme backup 12 years... When spec'ing the tub filler, I made sure to use one that ran full bore, knowing that a slow filling tub is a PITA. When the cold tap is full open, it steals pressure from the cold supply to the water heater and with the air lock, no hot water flows despite the hot tap also being open.
Now, the wife knows the ratio of hot to cold what the tub usually requires, and she goes about her way, first setting the cold, then the hot, and fills the tub, with... get this, cold water. At this point, I'm in hot water or the doghouse or (insert fav euphemism here). Telling her to run the hot to purge the air seems simple enough but she's not buying it. Trying to explain to her why it does what it does in technical terms and how to prevent it buys me no brownie points. You'd think that in 12 years, that this sort of thing would have manifested long ago. By her logic, my logic must be flawed since this is only the second time in 12 years (twice this month to boot) that she stepped into a soaker tub full of cold water. What are the odds?
Redoing the supply line to the WH is not an option. Remembering to purge the air every morning just in case it happens again, is not practical. BTW, she has also complained that it takes way too long for the water to run hot at her sink. So... I start to think, maybe I can solve both problems with a recirc pump, however I have no way to run a return line.
Enter the Grundfos Instant Hot Water Recirculation Kit with the crossover valve at the point of use. I am trying to understand how it works. I'm guessing that it provides a few PSI boost on the hot water line, just enough to create flow to the crossover with a temperature regulated valve that opens when cold and closes when warm. With the weight of 5 feet of water, it would need at least 2 PSI just to overcome the airlock. I cannot cut the recirc into the high point of the hot water line as the pump would lose its prime. Does the recirc have to be on the hot side or could it be cut into the cold supply?
If that won't work, should I just cut in an automatic air vent as is used in Hydronic heating systems? Help save my marriage.
When this aerated water is heated in the tank, some of the entrained air is released causing an air lock in the plumbing. When drawing warm water, I always draw just hot at first to purge the cold water (and the air) from the line. When, and only when it runs hot, I mix in cold to achieve the desired temp. Been doing it this way for 12 years.
Enter the wife... she has a large soaker tub... lemme backup 12 years... When spec'ing the tub filler, I made sure to use one that ran full bore, knowing that a slow filling tub is a PITA. When the cold tap is full open, it steals pressure from the cold supply to the water heater and with the air lock, no hot water flows despite the hot tap also being open.
Now, the wife knows the ratio of hot to cold what the tub usually requires, and she goes about her way, first setting the cold, then the hot, and fills the tub, with... get this, cold water. At this point, I'm in hot water or the doghouse or (insert fav euphemism here). Telling her to run the hot to purge the air seems simple enough but she's not buying it. Trying to explain to her why it does what it does in technical terms and how to prevent it buys me no brownie points. You'd think that in 12 years, that this sort of thing would have manifested long ago. By her logic, my logic must be flawed since this is only the second time in 12 years (twice this month to boot) that she stepped into a soaker tub full of cold water. What are the odds?
Redoing the supply line to the WH is not an option. Remembering to purge the air every morning just in case it happens again, is not practical. BTW, she has also complained that it takes way too long for the water to run hot at her sink. So... I start to think, maybe I can solve both problems with a recirc pump, however I have no way to run a return line.
Enter the Grundfos Instant Hot Water Recirculation Kit with the crossover valve at the point of use. I am trying to understand how it works. I'm guessing that it provides a few PSI boost on the hot water line, just enough to create flow to the crossover with a temperature regulated valve that opens when cold and closes when warm. With the weight of 5 feet of water, it would need at least 2 PSI just to overcome the airlock. I cannot cut the recirc into the high point of the hot water line as the pump would lose its prime. Does the recirc have to be on the hot side or could it be cut into the cold supply?
If that won't work, should I just cut in an automatic air vent as is used in Hydronic heating systems? Help save my marriage.
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