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Okay, let’s see if I can describe this. I have a boiler for my heat, with one additional loop that heats the domestic hot water in a tank that’s off to the side. When the DHW leaves the tank, it tees into two branches with their own shut offs. One branch serves the kitchen and the one finished bathroom. The second branch serves the laundry and the master bath, which is at this point only roughed in.
This set up has been working just fine for a year, except for one small glitch. This glitch was, I think, due to the fact that I hadn’t installed a check valve in the cold-water feed to the water heater. I believe that a convective loop developed, which meant that when we turned on cold water, we’d get a brief burst of hot water until the line flushed. Not a big deal, but an energy waster. So, this past week, I installed a check valve and an expansion tank in the cold-water feed branch. Problem solved.
Except… that our water temp at the taps dropped to about 95F. I’m not man enough to shower in that, and my wife certainly isn’t. The water coming off the heater was at about 130F. I fiddled and fretted all day yesterday and got nowhere. I called the oil-burner-service guy today, and he scratched his head for awhile. Then, he concluded that the DHW was mixing with the DCW somewhere, and shut off the DHW to the laundry/master bath loop. Symptom cured, there’s HW in the kitchen and main bath.
I figured that one of the roughed-in shower valves in the master bath might be open, and the water was mixing in there. Tonight, I closed both shower valves, and re-opened the DHW feed to that loop. Problem returns — DHW in the other loop is down into the 90s. I’ve shut the DHW down to the laundry loop for now, but that’s no permanent solution. Does anyone have any ideas?
As an aside, when the oil-burner guy was here today, he hinted that, because we use so little oil, he thought we might be cheating on our contract and buying oil from another supplier. I really love my dense-pack cellulose insulation.
Andy
Replies
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Okay, let's see if I can describe this. I have a boiler for my heat, with one additional loop that heats the domestic hot water in a tank that's off to the side. When the DHW leaves the tank, it tees into two branches with their own shut offs. One branch serves the kitchen and the one finished bathroom. The second branch serves the laundry and the master bath, which is at this point only roughed in.
This set up has been working just fine for a year, except for one small glitch. This glitch was, I think, due to the fact that I hadn't installed a check valve in the cold-water feed to the water heater. I believe that a convective loop developed, which meant that when we turned on cold water, we'd get a brief burst of hot water until the line flushed. Not a big deal, but an energy waster. So, this past week, I installed a check valve and an expansion tank in the cold-water feed branch. Problem solved.
Except... that our water temp at the taps dropped to about 95F. I'm not man enough to shower in that, and my wife certainly isn't. The water coming off the heater was at about 130F. I fiddled and fretted all day yesterday and got nowhere. I called the oil-burner-service guy today, and he scratched his head for awhile. Then, he concluded that the DHW was mixing with the DCW somewhere, and shut off the DHW to the laundry/master bath loop. Symptom cured, there's HW in the kitchen and main bath.
I figured that one of the roughed-in shower valves in the master bath might be open, and the water was mixing in there. Tonight, I closed both shower valves, and re-opened the DHW feed to that loop. Problem returns -- DHW in the other loop is down into the 90s. I've shut the DHW down to the laundry loop for now, but that's no permanent solution. Does anyone have any ideas?
As an aside, when the oil-burner guy was here today, he hinted that, because we use so little oil, he thought we might be cheating on our contract and buying oil from another supplier. I really love my dense-pack cellulose insulation.
Andy