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I installed an in-line gas water heater French made Aqua-Star) about 4 years ago. All pipe from the meter in is new copper. It’s been fine until recently when our hot water flow drops off noticeably after about 30 seconds of being turned on. Cold water flow remains good, so the heater might be the culprit. But pretty much it’s just copper pipe with gas jets under it, so I’m confused as to the problem.
Anyone familiar with this?
Bob Muzzy
Replies
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Seems that the water must be colder or the the heater burning less gas after the first 30 seconds - either could be possibilities. I certainly notice once the 38F water from the city's water main gets to the faucet. It takes 20-50 seconds to displace the 70F cold water in the pipes and cool the pipes off before dropping in temperature at various fixtures. So your heater input might be constant, but both the hot and cold water colder after 30 seconds. At this time of year, the cold front from winter 2000/2001 is getting down to the 10-15 depth of city water mains, so your incoming water may the coldest of the year.
For the heater to be putting out less heat, it has to be burning less gas (if gas is unburned, you have serious efficiency and safety problems from CO gas). To check gas consumption, I'd time the rotation of the 1/2 cubic foot needle on your gas meter during both initial and long-term operation. If the needle's speed goes, for instance, from 14.4 seconds per rotation (125,000 BTU/hour) to 8.6 seconds per rotation (75,000 BTU/hour), you are burning a lot less gas after the first 30 seconds and can focus on that as the problem.
Lastly, this may be a problem or characteristic of a temperature and pressure-compensated shower valve. Does is affect all the fixtures in the house, or just one? -David
*Try the simple stuff first. The aqua-star has a screen filter just as the water enters the heater check to see if its clear. flush the pipe anyway. I had a odd problem with a faucet which turned out to be a chunk of dirt that moved with the water flow and clogged the pipe after a brief turn on.
*I agree that Nigel's got a simpler thing to try to first. And in re-reading your post, you did say FLOW drops off, not temperature.
*How about the most simplest thing of all?Did you change the shower fawcet washer?I have found that newer rubber fawcet washers do swell when the heat reaches them and I will have to increase the opening (turn the knob) more during that phase (up to a minute or two before it stabilizes). Old washers will be rather hard and you won't see as much of this. This will make it seem like the flow is dropping off.I have noticed this and now I turn on the shower with more hot than I will need, and after a minute or two everything is ready for me to get in.But why it only started in your house after installing the new water heater is curious. Unless you were less critical with the old heater and only just now noticing it?Or did someone else take the first shower each day until now so you did not experience this morning warmup before?just some thoughts.
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I installed an in-line gas water heater French made Aqua-Star) about 4 years ago. All pipe from the meter in is new copper. It's been fine until recently when our hot water flow drops off noticeably after about 30 seconds of being turned on. Cold water flow remains good, so the heater might be the culprit. But pretty much it's just copper pipe with gas jets under it, so I'm confused as to the problem.
Anyone familiar with this?
Bob Muzzy