The Tank › Shower temperature
- November 11, 2010 at 12:16 am #14453
This isn’t a problem (I don’t think), but am just trying to understand what I’m seeing.
I recently (finally) completed a project where I replaced a single 50-gal. 50K BTU gas water heater, with an identical pair of 40-gal. 50K BTU gas Bradford White heaters, installed 6′ away from where the original heater was. Obviously this involved re-routing gas, vent, and water lines. I plumbed the new heaters in series.
Because of a health problem in the family, the water could only be turned off for so long, and as a result I only got one of the new heaters up and running on the first day. Everything seemed to work perfectly. Max. temp measured at the kitchen tap was 121F. At my next shower I noted where the (Moen) valve was positioned to achieve my comfortable water temp (pretty much centered).
A week later I finished getting the 2nd heater installed. Once again everything went as planned and I set the temp control on the heater to the same position as the first heater. A couple days later after I was certain all air was out of the system, etc., I re-checked the max temp at the same kitchen tap. Once again it was 121F, as I expected. However, to get the same comfort level in the same shower, the valve has to be noticeably farther to the hot side. Temperatures inside and outside the house have been about the same over this time period. All temp checks and showers were done when both heaters were fully recovered.
What could explain the shower difference after adding the 2nd heater?November 11, 2010 at 1:27 am #14456Larry WeingartenParticipant
Hello: You have two heaters in series. Is the “just added” heater up or down stream from the first heater?
Yours, LarryNovember 11, 2010 at 1:29 am #14457
The 2nd heater added is downstream (it receives the output of the 1st heater).November 11, 2010 at 9:36 pm #14460energyexpertParticipant
What is your water supply? Well temperatures change very slowly over time. However, if your public supply is a river or open reservoir a heavy cold rain or cold front could change the water supply temperature significantly. During the first test you may have had equal parts hot and cold. If the supply temperature drops you will find you are using more hot and less cold to achieve the same final temperature.
During summer school in Raleigh, NC in 1975 the cold was so hot I just took “cold” showers.
DavidNovember 11, 2010 at 11:20 pm #14461
Good point David, and thanks for replying. As it happens, this is public supply and we’ve had a stretch of several weeks where there has been no rain and very even temps from day to day.November 12, 2010 at 12:19 pm #14463Larry WeingartenParticipant
Hello: Since you’re getting good temperature at the kitchen, it’s likely not a heater problem, though you could verify this by measuring the actual output temp from the heater. If there is a recirc line, you might be getting some backflow. If there is a cross connection in the plumbing, that could do it. Or, (remote possibility) if you have a pressure / temperature balanced shower valve, it could be in need of cleaning or adjustment.
One thing we all do is to look for cause and effect, but that sometimes hampers troubleshooting as we assume too much. The misbehaving shower likely has something to do with a change at the heaters, but it might not 😉
Yours, LarryNovember 12, 2010 at 12:36 pm #14464
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