recirculation sediment problem

Old 01-06-08, 06:06 AM
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recirculation sediment problem

I have been in this house for 10 years. I am on a well, and have two hot water tanks set up to work in parallel. I am getting a sediment discharge in my hot water, only from my upstairs faucets and showers. The hot water tanks were extremly dirty and it took several drainings and flushings to clear most of the debris. Apparently, I have a recirculating system, as I notice copper pipes entering the drain valves at the bottom of the tank. I see no pumps anywhere on the system, nor have I heard anything "pumping" since I have been in this house. The recirculating pipes branch off in two opposite directions to either side of the house. The recirculating system seems to work fairly well on one side of the house (although lately nowhere as good as in the past). I see no positive results on the other side of the house, where I traced that circulating line. Indeed that side of the house, be it upstairs or downstairs, never showed any benefits of instant hot water.

The recirculating lines are very hot for about 10-15 feet as they join the bottom of the hot water tanks. I see no check valve anywhere. I suspect I am getting backflow up the recirculating pipes with hot water off the bottom of the tanks. Is it possible that sediment off the bottom of the tank could be pushed up to my second floor faucets via the recirculating lines causing the sediment discharge? The upstairs faucets in the master bathroom with the fastest hot water, discharge the most debris. However, in a second upstairs bathroom there is discharge from one sink faucet and the bathtub faucet (the instant hot water, if installed in both faucets works poorly, if at all). Interestingly, I see no discharge from the second sink faucet in that bathroom. A third bathroom upstairs discharges in a similar fashion to this latter bathroom, but the instant hot water appears to work (this is on the same side of the house as the master bathroom, and must feed off the same branch of that end of the recirculator. The other bathroom, that works poorly, if at all, is at the far end of the house and has a long (25-50 foot) horizontal run to the water heater. I don't see how that could work properly on a gravity based system ? In summary, how do I stop this sediment discharge, and secondarily, how do I fix my recirculating system on the other side of the house? Thank you
Old 01-06-08, 04:08 PM
Join Date: Mar 2006
Location: Wet side of Washington state.
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Step one, you need check valves on the recirculation lines where they connect to the bottom of the heater(s).

Step two, there needs to be a definite height differential between the connection on the hot water distribution to the recirculation line and the connection at the bottom of the heater. The greater this height difference the better the gravity system will work. If you do not have enough height differential then you will need to install a pump.

Step three, will require you to flush the heater(s) on a periodic basis, maybe once a month if your water has a lot of sediment. A large whole-house filter unit may be required.

There are other things that may come into play depending on how your system is set up. Having two water heaters in parallel connection is not the best.

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