Loss of all pressure and hot water. Cold works fine. I have two (2) Noritz tankless heaters
Thanks
Erik

Is this just at one faucet or all of your faucets? Are you two tanks servicing different zones in the home or are they hooked in series?

Hooked in series and all faucets and taps affected

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Originally Posted by Erik2233

I have a loss of all pressure and hot water. The tankless heaters are hooked in series and all faucets and taps affected

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Are you sayimg that in addition to loss of pressure that you don't have any hot water either?
If you have good pressure and volume on the cold side then that puts the problem in the heaters or the line that exits them. That's where I would start checking. Do you have a high mineral content that could be clogging the output of the tankless heaters? Are you quite certain that the cold water supply to the tankless heaters has enough volume to maintain pressure? Do some checking and get back to me. Regards, Tom

If you tankless units are installed to code you have several places where you can open the system in case you had to remove unit. I'd open that last connection on the outlet side just to see if the blockage is upstream or downstream of the heaters. Double check all the inlet and outlet valves, you should have at least 4 valves so make sure they are all open. Just a side question about why thess units are in series. If they are set to the same temp the first one heats the water to 120 and the second unit won't be doing anything. Can you explain the rationale for us? Thanks