Question about Rinnai Webstone The isolator EXP tankless water heater Service Valves WRIK

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I have a Rinnai tankless. The temperature fluctuates wildly

I suffer occasional loss of heat in the sinks but the basement shower is the worst. Temperature will fluctuate from burning hot to icy cold withing seconds with touching the controls. This will last for months, and then not happen again for a while. First my serviceman thought our pipes might be clogged with sediment, but they are pretty new. Then he thought there wasn’t enough gas coming into the house, so now we have enough for an apartment building.

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  • Maine 1234 Jan 20, 2009

    I have a similar problem. The temperature in our showers slowly goes from too hot to too cold over a 20 second interval. I had a repair guy come without success. The one insight I do have is that we installed a low flow shower head about 8 months ago, when the problem “might” have started and I think the low flow is a problem for the water heater. At the low flow the heater switches from high heat to low heat but never to the right heat. I’ve switched to a normal shower head and the problem is better but not solved. My family is still not satisfied so I’m interested in for information.

  • gsalexander Feb 03, 2009

    when i set the temp it will not reach the 125 degree temp that its set at.

  • jimbeam4me Feb 15, 2009

    hi we have the rinnai 20 hot water (tankless) but the hot water go colder as you use it this has goten worse over time now you are turning the tap up just to get hot water then you have to turn it down so that you are not burnt we have 9lt slow shower heads & its take 6/8 month to get to the point that you are turning the taps constontly just to get hot water we have no controlers on the system

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I think the dip tube in your water heater has failed, this is a plastic tube that goes in the cold side of your tank and forces incoming cold water to the bottom of the tank allowing hot water out at the top. When this tube deteiorates the incoming cold water mixes at the top of the tank causing the problem you have. the dip tube runs about 5 bucks but takes someone with pluming skills to install.

Posted on Jan 09, 2009

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Water temperature fluctuates with tankless


Have you ever tried to pump water for a fountain... It is so tough and you need larger and larger pumps to get it to go 7 feet high to let's say 10 feet high. Having the on demand water heater in the attic dramatically drops it's pressure. It's best to feed it with a 1 inch or at least 3/4 inch pipe downstairs before it splits the hot and the cold to get the best pressure everywhere then the least pressure will be when it reaches the 2nd floor. but the heater won't cut out because the pressure it even greater downstairs.

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Bad PC board.
Bad sensor.
Don't buy a tankless because the problems can be endless.

Before blaming the tankless however.
Perform the yearly required maintenance on burner
Delime the unit.
http://waterheatertimer.org/pdf/Bosch_Descaling-heat-exchanger.pdf

Remove and clean aerators, replace low-flow shower heads with large water-wasting shower heads.

IMPORTANT check all your single-handle faucets for crossover.
Water getting cool after 15 minutes could be bad cartridge on another faucet.
http://waterheatertimer.org/Crossover.html
http://waterheatertimer.org/pdf/No-Error-Code.pdf

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4_5_2012_1_19_13_am.jpg

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